Make all nodes contain Raw

WIP
2022-08-22 21:05:41 -04:00 · 2022-08-22 23:04:44 +00:00
49 changed files with 1870 additions and 4254 deletions
@@ -1,26 +0,0 @@
-name: CIFuzz
-on: [pull_request]
-jobs:
-  Fuzzing:
-    runs-on: ubuntu-latest
-    steps:
-    - name: Build Fuzzers
-      id: build
-      uses: google/oss-fuzz/infra/cifuzz/actions/build_fuzzers@master
-      with:
-        oss-fuzz-project-name: 'go-toml'
-        dry-run: false
-        language: go
-    - name: Run Fuzzers
-      uses: google/oss-fuzz/infra/cifuzz/actions/run_fuzzers@master
-      with:
-        oss-fuzz-project-name: 'go-toml'
-        fuzz-seconds: 300
-        dry-run: false
-        language: go
-    - name: Upload Crash
-      uses: actions/upload-artifact@v3
-      if: failure() && steps.build.outcome == 'success'
-      with:
-        name: artifacts
-        path: ./out/artifacts
@@ -35,7 +35,7 @@ jobs:

    steps:
    - name: Checkout repository
-      uses: actions/checkout@v4
+      uses: actions/checkout@v3

    # Initializes the CodeQL tools for scanning.
    - name: Initialize CodeQL
@@ -9,12 +9,12 @@ jobs:
    runs-on: "ubuntu-latest"
    name: report
    steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v3
        with:
          fetch-depth: 0
      - name: Setup go
-        uses: actions/setup-go@v4
+        uses: actions/setup-go@master
        with:
-          go-version: "1.21"
+          go-version: 1.19
      - name: Run tests with coverage
        run: ./ci.sh coverage -d "${GITHUB_BASE_REF-HEAD}"
@@ -16,15 +16,15 @@ jobs:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout
-        uses: actions/checkout@v4
+        uses: actions/checkout@v3
        with:
          fetch-depth: 0
      - name: Set up Go
-        uses: actions/setup-go@v4
+        uses: actions/setup-go@v2
        with:
-          go-version: "1.21"
+          go-version: 1.19
      - name: Login to GitHub Container Registry
-        uses: docker/login-action@v3
+        uses: docker/login-action@v2
        with:
          registry: ghcr.io
          username: ${{ github.actor }}
@@ -12,15 +12,15 @@ jobs:
    strategy:
      matrix:
        os: [ 'ubuntu-latest', 'windows-latest', 'macos-latest']
-        go: [ '1.20', '1.21' ]
+        go: [ '1.18', '1.19' ]
    runs-on: ${{ matrix.os }}
    name: ${{ matrix.go }}/${{ matrix.os }}
    steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v3
        with:
          fetch-depth: 0
      - name: Setup go ${{ matrix.go }}
-        uses: actions/setup-go@v4
+        uses: actions/setup-go@master
        with:
          go-version: ${{ matrix.go }}
      - name: Run unit tests
@@ -4,4 +4,3 @@ cmd/tomll/tomll
 cmd/tomljson/tomljson
 cmd/tomltestgen/tomltestgen
 dist
-tests/
@@ -18,7 +18,6 @@ builds:
      - linux_amd64
      - linux_arm64
      - linux_arm
-      - linux_riscv64
      - windows_amd64
      - windows_arm64
      - windows_arm
@@ -38,7 +37,6 @@ builds:
      - linux_amd64
      - linux_arm64
      - linux_arm
-      - linux_riscv64
      - windows_amd64
      - windows_arm64
      - windows_arm
@@ -57,7 +55,6 @@ builds:
    targets:
      - linux_amd64
      - linux_arm64
-      - linux_riscv64
      - linux_arm
      - windows_amd64
      - windows_arm64
@@ -1,7 +1,6 @@
 The MIT License (MIT)

-go-toml v2
-Copyright (c) 2021 - 2023 Thomas Pelletier
+Copyright (c) 2013 - 2022 Thomas Pelletier, Eric Anderton

 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
@@ -45,15 +45,16 @@ to check for typos. [See example in the documentation][strict].

 ### Contextualized errors

-When most decoding errors occur, go-toml returns [`DecodeError`][decode-err],
+When most decoding errors occur, go-toml returns [`DecodeError`][decode-err]),
 which contains a human readable contextualized version of the error. For
 example:

 ```
-1| [server]
-2| path = 100
- |        ~~~ cannot decode TOML integer into struct field toml_test.Server.Path of type string
-3| port = 50
+2| key1 = "value1"
+3| key2 = "missing2"
+ | ~~~~ missing field
+4| key3 = "missing3"
+5| key4 = "value4"
 ```

 [decode-err]: https://pkg.go.dev/github.com/pelletier/go-toml/v2#DecodeError
@@ -72,26 +73,6 @@ representation.
 [tlt]: https://pkg.go.dev/github.com/pelletier/go-toml/v2#LocalTime
 [tldt]: https://pkg.go.dev/github.com/pelletier/go-toml/v2#LocalDateTime

-### Commented config
-
-Since TOML is often used for configuration files, go-toml can emit documents
-annotated with [comments and commented-out values][comments-example]. For
-example, it can generate the following file:
-
-```toml
-# Host IP to connect to.
-host = '127.0.0.1'
-# Port of the remote server.
-port = 4242
-
-# Encryption parameters (optional)
-# [TLS]
-# cipher = 'AEAD-AES128-GCM-SHA256'
-# version = 'TLS 1.3'
-```
-
-[comments-example]: https://pkg.go.dev/github.com/pelletier/go-toml/v2#example-Marshal-Commented
-
 ## Getting started

 Given the following struct, let's see how to read it and write it as TOML:
@@ -159,17 +140,6 @@ fmt.Println(string(b))

 [marshal]: https://pkg.go.dev/github.com/pelletier/go-toml/v2#Marshal

-## Unstable API
-
-This API does not yet follow the backward compatibility guarantees of this
-library. They provide early access to features that may have rough edges or an
-API subject to change.
-
-### Parser
-
-Parser is the unstable API that allows iterative parsing of a TOML document at
-the AST level. See https://pkg.go.dev/github.com/pelletier/go-toml/v2/unstable.
-
 ## Benchmarks

 Execution time speedup compared to other Go TOML libraries:
@@ -179,12 +149,12 @@ Execution time speedup compared to other Go TOML libraries:
        <tr><th>Benchmark</th><th>go-toml v1</th><th>BurntSushi/toml</th></tr>
    </thead>
    <tbody>
-        <tr><td>Marshal/HugoFrontMatter-2</td><td>1.9x</td><td>2.2x</td></tr>
-        <tr><td>Marshal/ReferenceFile/map-2</td><td>1.7x</td><td>2.1x</td></tr>
-        <tr><td>Marshal/ReferenceFile/struct-2</td><td>2.2x</td><td>3.0x</td></tr>
-        <tr><td>Unmarshal/HugoFrontMatter-2</td><td>2.9x</td><td>2.7x</td></tr>
-        <tr><td>Unmarshal/ReferenceFile/map-2</td><td>2.6x</td><td>2.7x</td></tr>
-        <tr><td>Unmarshal/ReferenceFile/struct-2</td><td>4.6x</td><td>5.1x</td></tr>
+        <tr><td>Marshal/HugoFrontMatter-2</td><td>1.9x</td><td>1.9x</td></tr>
+        <tr><td>Marshal/ReferenceFile/map-2</td><td>1.7x</td><td>1.8x</td></tr>
+        <tr><td>Marshal/ReferenceFile/struct-2</td><td>2.2x</td><td>2.5x</td></tr>
+        <tr><td>Unmarshal/HugoFrontMatter-2</td><td>2.9x</td><td>2.9x</td></tr>
+        <tr><td>Unmarshal/ReferenceFile/map-2</td><td>2.6x</td><td>2.9x</td></tr>
+        <tr><td>Unmarshal/ReferenceFile/struct-2</td><td>4.4x</td><td>5.3x</td></tr>
     </tbody>
 </table>
 <details><summary>See more</summary>
@@ -197,17 +167,17 @@ provided for completeness.</p>
        <tr><th>Benchmark</th><th>go-toml v1</th><th>BurntSushi/toml</th></tr>
    </thead>
    <tbody>
-        <tr><td>Marshal/SimpleDocument/map-2</td><td>1.8x</td><td>2.7x</td></tr>
-        <tr><td>Marshal/SimpleDocument/struct-2</td><td>2.7x</td><td>3.8x</td></tr>
-        <tr><td>Unmarshal/SimpleDocument/map-2</td><td>3.8x</td><td>3.0x</td></tr>
-        <tr><td>Unmarshal/SimpleDocument/struct-2</td><td>5.6x</td><td>4.1x</td></tr>
-        <tr><td>UnmarshalDataset/example-2</td><td>3.0x</td><td>3.2x</td></tr>
-        <tr><td>UnmarshalDataset/code-2</td><td>2.3x</td><td>2.9x</td></tr>
-        <tr><td>UnmarshalDataset/twitter-2</td><td>2.6x</td><td>2.7x</td></tr>
-        <tr><td>UnmarshalDataset/citm_catalog-2</td><td>2.2x</td><td>2.3x</td></tr>
-        <tr><td>UnmarshalDataset/canada-2</td><td>1.8x</td><td>1.5x</td></tr>
-        <tr><td>UnmarshalDataset/config-2</td><td>4.1x</td><td>2.9x</td></tr>
-        <tr><td>geomean</td><td>2.7x</td><td>2.8x</td></tr>
+        <tr><td>Marshal/SimpleDocument/map-2</td><td>1.8x</td><td>2.9x</td></tr>
+        <tr><td>Marshal/SimpleDocument/struct-2</td><td>2.7x</td><td>4.2x</td></tr>
+        <tr><td>Unmarshal/SimpleDocument/map-2</td><td>4.5x</td><td>3.1x</td></tr>
+        <tr><td>Unmarshal/SimpleDocument/struct-2</td><td>6.2x</td><td>3.9x</td></tr>
+        <tr><td>UnmarshalDataset/example-2</td><td>3.1x</td><td>3.5x</td></tr>
+        <tr><td>UnmarshalDataset/code-2</td><td>2.3x</td><td>3.1x</td></tr>
+        <tr><td>UnmarshalDataset/twitter-2</td><td>2.5x</td><td>2.6x</td></tr>
+        <tr><td>UnmarshalDataset/citm_catalog-2</td><td>2.1x</td><td>2.2x</td></tr>
+        <tr><td>UnmarshalDataset/canada-2</td><td>1.6x</td><td>1.3x</td></tr>
+        <tr><td>UnmarshalDataset/config-2</td><td>4.3x</td><td>3.2x</td></tr>
+        <tr><td>[Geo mean]</td><td>2.7x</td><td>2.8x</td></tr>
     </tbody>
 </table>
 <p>This table can be generated with <code>./ci.sh benchmark -a -html</code>.</p>
@@ -516,20 +486,27 @@ is not necessary anymore.

 V1 used to provide multiple struct tags: `comment`, `commented`, `multiline`,
 `toml`, and `omitempty`. To behave more like the standard library, v2 has merged
-`toml`, `multiline`, `commented`, and `omitempty`. For example:
+`toml`, `multiline`, and `omitempty`. For example:

 ```go
 type doc struct {
 	// v1
-	F string `toml:"field" multiline:"true" omitempty:"true" commented:"true"`
+	F string `toml:"field" multiline:"true" omitempty:"true"`
 	// v2
-	F string `toml:"field,multiline,omitempty,commented"`
+	F string `toml:"field,multiline,omitempty"`
 }
 ```

 Has a result, the `Encoder.SetTag*` methods have been removed, as there is just
 one tag now.

+
+#### `commented` tag has been removed
+
+There is no replacement for the `commented` tag. This feature would be better
+suited in a proper document model for go-toml v2, which has been [cut from
+scope][nodoc] at the moment.
+
 #### `Encoder.ArraysWithOneElementPerLine` has been renamed

 The new name is `Encoder.SetArraysMultiline`. The behavior should be the same.
@@ -565,7 +542,7 @@ complete solutions exist out there.

 ## Versioning

-Go-toml follows [Semantic Versioning](https://semver.org). The supported version
+Go-toml follows [Semantic Versioning](http://semver.org/). The supported version
 of [TOML](https://github.com/toml-lang/toml) is indicated at the beginning of
 this document. The last two major versions of Go are supported
 (see [Go Release Policy](https://golang.org/doc/devel/release.html#policy)).
@@ -2,6 +2,9 @@

 ## Supported Versions

+Use this section to tell people about which versions of your project are
+currently being supported with security updates.
+
 | Version    | Supported          |
 | ---------- | ------------------ |
 | Latest 2.x | :white_check_mark: |
@@ -1,4 +1,4 @@
-package unstable
+package toml

 import (
 	"bytes"
@@ -55,7 +55,7 @@ func BenchmarkParseLiteralStringValid(b *testing.B) {

 	for name, input := range inputs {
 		b.Run(name, func(b *testing.B) {
-			p := Parser{}
+			p := parser{}
 			b.SetBytes(int64(len(input)))
 			b.ReportAllocs()
 			b.ResetTimer()
@@ -77,9 +77,8 @@ cover() {

    pushd "$dir"
    go test -covermode=atomic  -coverpkg=./... -coverprofile=coverage.out.tmp ./...
-    grep -Ev '(fuzz|testsuite|tomltestgen|gotoml-test-decoder|gotoml-test-encoder)' coverage.out.tmp > coverage.out
+    cat coverage.out.tmp | grep -v testsuite | grep -v tomltestgen | grep -v gotoml-test-decoder > coverage.out
    go tool cover -func=coverage.out
-    echo "Coverage profile for ${branch}: ${dir}/coverage.out" >&2
    popd

    if [ "${branch}" != "HEAD" ]; then
@@ -152,7 +151,7 @@ bench() {
    fi

    export GOMAXPROCS=2
-    go test '-bench=^Benchmark(Un)?[mM]arshal' -count=10 -run=Nothing ./... | tee "${out}"
+    nice -n -19 taskset --cpu-list 0,1 go test '-bench=^Benchmark(Un)?[mM]arshal' -count=5 -run=Nothing ./... | tee "${out}"
    popd

    if [ "${branch}" != "HEAD" ]; then
@@ -161,12 +160,10 @@ bench() {
 }

 fmktemp() {
-    if mktemp --version &> /dev/null; then
-	# GNU
-        mktemp --suffix=-$1
+    if mktemp --version|grep GNU >/dev/null; then
+        mktemp --suffix=-$1;
    else
-	# BSD
-	mktemp -t $1
+        mktemp -t $1;
    fi
 }

@@ -186,14 +183,12 @@ with open(sys.argv[1]) as f:
            lines.append(line.split(','))

 results = []
-for line in reversed(lines[2:]):
-    if len(line) < 8 or line[0] == "":
-        continue
+for line in reversed(lines[1:]):
    v2 = float(line[1])
    results.append([
        line[0].replace("-32", ""),
        "%.1fx" % (float(line[3])/v2),  # v1
-        "%.1fx" % (float(line[7])/v2),  # bs
+        "%.1fx" % (float(line[5])/v2),  # bs
    ])
 # move geomean to the end
 results.append(results[0])
@@ -264,10 +259,10 @@ benchmark() {

        if [ "$1" = "-html" ]; then
            tmpcsv=`fmktemp csv`
-            benchstat -format csv go-toml-v2.txt go-toml-v1.txt bs-toml.txt > $tmpcsv
+            benchstat -csv -geomean go-toml-v2.txt go-toml-v1.txt bs-toml.txt > $tmpcsv
            benchstathtml $tmpcsv
        else
-            benchstat go-toml-v2.txt go-toml-v1.txt bs-toml.txt
+            benchstat -geomean go-toml-v2.txt go-toml-v1.txt bs-toml.txt
        fi

        rm -f go-toml-v2.txt go-toml-v1.txt bs-toml.txt
@@ -1,30 +0,0 @@
-package main
-
-import (
-	"flag"
-	"log"
-	"os"
-	"path"
-
-	"github.com/pelletier/go-toml/v2/internal/testsuite"
-)
-
-func main() {
-	log.SetFlags(0)
-	flag.Usage = usage
-	flag.Parse()
-	if flag.NArg() != 0 {
-		flag.Usage()
-	}
-
-	err := testsuite.EncodeStdin()
-	if err != nil {
-		log.Fatal(err)
-	}
-}
-
-func usage() {
-	log.Printf("Usage: %s < toml-file\n", path.Base(os.Args[0]))
-	flag.PrintDefaults()
-	os.Exit(1)
-}
@@ -7,13 +7,17 @@
 package main

 import (
+	"archive/zip"
 	"bytes"
 	"flag"
 	"fmt"
 	"go/format"
+	"io"
+	"io/ioutil"
 	"log"
+	"net/http"
 	"os"
-	"path/filepath"
+	"regexp"
 	"strconv"
 	"strings"
 	"text/template"
@@ -60,6 +64,30 @@ const srcTemplate = "// Generated by tomltestgen for toml-test ref {{.Ref}} on {
 	"}\n" +
 	"{{end}}\n"

+func downloadTmpFile(url string) string {
+	log.Println("starting to download file from", url)
+	resp, err := http.Get(url)
+	if err != nil {
+		panic(err)
+	}
+	defer resp.Body.Close()
+
+	tmpfile, err := ioutil.TempFile("", "toml-test-*.zip")
+	if err != nil {
+		panic(err)
+	}
+	defer tmpfile.Close()
+
+	copiedLen, err := io.Copy(tmpfile, resp.Body)
+	if err != nil {
+		panic(err)
+	}
+	if resp.ContentLength > 0 && copiedLen != resp.ContentLength {
+		panic(fmt.Errorf("copied %d bytes, request body had %d", copiedLen, resp.ContentLength))
+	}
+	return tmpfile.Name()
+}
+
 func kebabToCamel(kebab string) string {
 	camel := ""
 	nextUpper := true
@@ -79,6 +107,19 @@ func kebabToCamel(kebab string) string {
 	return camel
 }

+func readFileFromZip(f *zip.File) string {
+	reader, err := f.Open()
+	if err != nil {
+		panic(err)
+	}
+	defer reader.Close()
+	bytes, err := ioutil.ReadAll(reader)
+	if err != nil {
+		panic(err)
+	}
+	return string(bytes)
+}
+
 func templateGoStr(input string) string {
 	return strconv.Quote(input)
 }
@@ -97,57 +138,61 @@ func main() {
 	flag.Usage = usage
 	flag.Parse()

+	url := "https://codeload.github.com/BurntSushi/toml-test/zip/" + *ref
+	resultFile := downloadTmpFile(url)
+	defer os.Remove(resultFile)
+	log.Println("file written to", resultFile)
+
+	zipReader, err := zip.OpenReader(resultFile)
+	if err != nil {
+		panic(err)
+	}
+	defer zipReader.Close()
+
 	collection := testsCollection{
 		Ref:       *ref,
 		Timestamp: time.Now().Format(time.RFC3339),
 	}

-	dirContent, _ := filepath.Glob("tests/invalid/**/*.toml")
-	for _, f := range dirContent {
-		filename := strings.TrimPrefix(f, "tests/valid/")
-		name := kebabToCamel(strings.TrimSuffix(filename, ".toml"))
+	zipFilesMap := map[string]*zip.File{}

-		log.Printf("> [%s] %s\n", "invalid", name)
-
-		tomlContent, err := os.ReadFile(f)
-		if err != nil {
-			fmt.Printf("failed to read test file: %s\n", err)
-			os.Exit(1)
+	for _, f := range zipReader.File {
+		zipFilesMap[f.Name] = f
 	}

+	testFileRegexp := regexp.MustCompile(`([^/]+/tests/(valid|invalid)/(.+))\.(toml)`)
+	for _, f := range zipReader.File {
+		groups := testFileRegexp.FindStringSubmatch(f.Name)
+		if len(groups) > 0 {
+			name := kebabToCamel(groups[3])
+			testType := groups[2]
+
+			log.Printf("> [%s] %s\n", testType, name)
+
+			tomlContent := readFileFromZip(f)
+
+			switch testType {
+			case "invalid":
 				collection.Invalid = append(collection.Invalid, invalid{
 					Name:  name,
-			Input: string(tomlContent),
+					Input: tomlContent,
 				})
 				collection.Count++
-	}
-
-	dirContent, _ = filepath.Glob("tests/valid/**/*.toml")
-	for _, f := range dirContent {
-		filename := strings.TrimPrefix(f, "tests/valid/")
-		name := kebabToCamel(strings.TrimSuffix(filename, ".toml"))
-
-		log.Printf("> [%s] %s\n", "valid", name)
-
-		tomlContent, err := os.ReadFile(f)
-		if err != nil {
-			fmt.Printf("failed reading test file: %s\n", err)
-			os.Exit(1)
-		}
-
-		filename = strings.TrimSuffix(f, ".toml")
-		jsonContent, err := os.ReadFile(filename + ".json")
-		if err != nil {
-			fmt.Printf("failed reading validation json: %s\n", err)
-			os.Exit(1)
-		}
+			case "valid":
+				baseFilePath := groups[1]
+				jsonFilePath := baseFilePath + ".json"
+				jsonContent := readFileFromZip(zipFilesMap[jsonFilePath])

 				collection.Valid = append(collection.Valid, valid{
 					Name:    name,
-			Input:   string(tomlContent),
-			JsonRef: string(jsonContent),
+					Input:   tomlContent,
+					JsonRef: jsonContent,
 				})
 				collection.Count++
+			default:
+				panic(fmt.Sprintf("unknown test type: %s", testType))
+			}
+		}
 	}

 	log.Printf("Collected %d tests from toml-test\n", collection.Count)
@@ -157,7 +202,7 @@ func main() {
 	}
 	t := template.Must(template.New("src").Funcs(funcMap).Parse(srcTemplate))
 	buf := new(bytes.Buffer)
-	err := t.Execute(buf, collection)
+	err = t.Execute(buf, collection)
 	if err != nil {
 		panic(err)
 	}
@@ -171,7 +216,7 @@ func main() {
 		return
 	}

-	err = os.WriteFile(*out, outputBytes, 0o644)
+	err = os.WriteFile(*out, outputBytes, 0644)
 	if err != nil {
 		panic(err)
 	}
@@ -5,8 +5,6 @@ import (
 	"math"
 	"strconv"
 	"time"
-
-	"github.com/pelletier/go-toml/v2/unstable"
 )

 func parseInteger(b []byte) (int64, error) {
@@ -34,7 +32,7 @@ func parseLocalDate(b []byte) (LocalDate, error) {
 	var date LocalDate

 	if len(b) != 10 || b[4] != '-' || b[7] != '-' {
-		return date, unstable.NewParserError(b, "dates are expected to have the format YYYY-MM-DD")
+		return date, newDecodeError(b, "dates are expected to have the format YYYY-MM-DD")
 	}

 	var err error
@@ -55,7 +53,7 @@ func parseLocalDate(b []byte) (LocalDate, error) {
 	}

 	if !isValidDate(date.Year, date.Month, date.Day) {
-		return LocalDate{}, unstable.NewParserError(b, "impossible date")
+		return LocalDate{}, newDecodeError(b, "impossible date")
 	}

 	return date, nil
@@ -66,7 +64,7 @@ func parseDecimalDigits(b []byte) (int, error) {

 	for i, c := range b {
 		if c < '0' || c > '9' {
-			return 0, unstable.NewParserError(b[i:i+1], "expected digit (0-9)")
+			return 0, newDecodeError(b[i:i+1], "expected digit (0-9)")
 		}
 		v *= 10
 		v += int(c - '0')
@@ -99,7 +97,7 @@ func parseDateTime(b []byte) (time.Time, error) {
 	} else {
 		const dateTimeByteLen = 6
 		if len(b) != dateTimeByteLen {
-			return time.Time{}, unstable.NewParserError(b, "invalid date-time timezone")
+			return time.Time{}, newDecodeError(b, "invalid date-time timezone")
 		}
 		var direction int
 		switch b[0] {
@@ -108,11 +106,11 @@ func parseDateTime(b []byte) (time.Time, error) {
 		case '+':
 			direction = +1
 		default:
-			return time.Time{}, unstable.NewParserError(b[:1], "invalid timezone offset character")
+			return time.Time{}, newDecodeError(b[:1], "invalid timezone offset character")
 		}

 		if b[3] != ':' {
-			return time.Time{}, unstable.NewParserError(b[3:4], "expected a : separator")
+			return time.Time{}, newDecodeError(b[3:4], "expected a : separator")
 		}

 		hours, err := parseDecimalDigits(b[1:3])
@@ -120,7 +118,7 @@ func parseDateTime(b []byte) (time.Time, error) {
 			return time.Time{}, err
 		}
 		if hours > 23 {
-			return time.Time{}, unstable.NewParserError(b[:1], "invalid timezone offset hours")
+			return time.Time{}, newDecodeError(b[:1], "invalid timezone offset hours")
 		}

 		minutes, err := parseDecimalDigits(b[4:6])
@@ -128,7 +126,7 @@ func parseDateTime(b []byte) (time.Time, error) {
 			return time.Time{}, err
 		}
 		if minutes > 59 {
-			return time.Time{}, unstable.NewParserError(b[:1], "invalid timezone offset minutes")
+			return time.Time{}, newDecodeError(b[:1], "invalid timezone offset minutes")
 		}

 		seconds := direction * (hours*3600 + minutes*60)
@@ -141,7 +139,7 @@ func parseDateTime(b []byte) (time.Time, error) {
 	}

 	if len(b) > 0 {
-		return time.Time{}, unstable.NewParserError(b, "extra bytes at the end of the timezone")
+		return time.Time{}, newDecodeError(b, "extra bytes at the end of the timezone")
 	}

 	t := time.Date(
@@ -162,7 +160,7 @@ func parseLocalDateTime(b []byte) (LocalDateTime, []byte, error) {

 	const localDateTimeByteMinLen = 11
 	if len(b) < localDateTimeByteMinLen {
-		return dt, nil, unstable.NewParserError(b, "local datetimes are expected to have the format YYYY-MM-DDTHH:MM:SS[.NNNNNNNNN]")
+		return dt, nil, newDecodeError(b, "local datetimes are expected to have the format YYYY-MM-DDTHH:MM:SS[.NNNNNNNNN]")
 	}

 	date, err := parseLocalDate(b[:10])
@@ -173,7 +171,7 @@ func parseLocalDateTime(b []byte) (LocalDateTime, []byte, error) {

 	sep := b[10]
 	if sep != 'T' && sep != ' ' && sep != 't' {
-		return dt, nil, unstable.NewParserError(b[10:11], "datetime separator is expected to be T or a space")
+		return dt, nil, newDecodeError(b[10:11], "datetime separator is expected to be T or a space")
 	}

 	t, rest, err := parseLocalTime(b[11:])
@@ -197,7 +195,7 @@ func parseLocalTime(b []byte) (LocalTime, []byte, error) {
 	// check if b matches to have expected format HH:MM:SS[.NNNNNN]
 	const localTimeByteLen = 8
 	if len(b) < localTimeByteLen {
-		return t, nil, unstable.NewParserError(b, "times are expected to have the format HH:MM:SS[.NNNNNN]")
+		return t, nil, newDecodeError(b, "times are expected to have the format HH:MM:SS[.NNNNNN]")
 	}

 	var err error
@@ -208,10 +206,10 @@ func parseLocalTime(b []byte) (LocalTime, []byte, error) {
 	}

 	if t.Hour > 23 {
-		return t, nil, unstable.NewParserError(b[0:2], "hour cannot be greater 23")
+		return t, nil, newDecodeError(b[0:2], "hour cannot be greater 23")
 	}
 	if b[2] != ':' {
-		return t, nil, unstable.NewParserError(b[2:3], "expecting colon between hours and minutes")
+		return t, nil, newDecodeError(b[2:3], "expecting colon between hours and minutes")
 	}

 	t.Minute, err = parseDecimalDigits(b[3:5])
@@ -219,10 +217,10 @@ func parseLocalTime(b []byte) (LocalTime, []byte, error) {
 		return t, nil, err
 	}
 	if t.Minute > 59 {
-		return t, nil, unstable.NewParserError(b[3:5], "minutes cannot be greater 59")
+		return t, nil, newDecodeError(b[3:5], "minutes cannot be greater 59")
 	}
 	if b[5] != ':' {
-		return t, nil, unstable.NewParserError(b[5:6], "expecting colon between minutes and seconds")
+		return t, nil, newDecodeError(b[5:6], "expecting colon between minutes and seconds")
 	}

 	t.Second, err = parseDecimalDigits(b[6:8])
@@ -231,7 +229,7 @@ func parseLocalTime(b []byte) (LocalTime, []byte, error) {
 	}

 	if t.Second > 60 {
-		return t, nil, unstable.NewParserError(b[6:8], "seconds cannot be greater 60")
+		return t, nil, newDecodeError(b[6:8], "seconds cannot be greater 60")
 	}

 	b = b[8:]
@@ -244,7 +242,7 @@ func parseLocalTime(b []byte) (LocalTime, []byte, error) {
 		for i, c := range b[1:] {
 			if !isDigit(c) {
 				if i == 0 {
-					return t, nil, unstable.NewParserError(b[0:1], "need at least one digit after fraction point")
+					return t, nil, newDecodeError(b[0:1], "need at least one digit after fraction point")
 				}
 				break
 			}
@@ -268,7 +266,7 @@ func parseLocalTime(b []byte) (LocalTime, []byte, error) {
 		}

 		if precision == 0 {
-			return t, nil, unstable.NewParserError(b[:1], "nanoseconds need at least one digit")
+			return t, nil, newDecodeError(b[:1], "nanoseconds need at least one digit")
 		}

 		t.Nanosecond = frac * nspow[precision]
@@ -291,24 +289,24 @@ func parseFloat(b []byte) (float64, error) {
 	}

 	if cleaned[0] == '.' {
-		return 0, unstable.NewParserError(b, "float cannot start with a dot")
+		return 0, newDecodeError(b, "float cannot start with a dot")
 	}

 	if cleaned[len(cleaned)-1] == '.' {
-		return 0, unstable.NewParserError(b, "float cannot end with a dot")
+		return 0, newDecodeError(b, "float cannot end with a dot")
 	}

 	dotAlreadySeen := false
 	for i, c := range cleaned {
 		if c == '.' {
 			if dotAlreadySeen {
-				return 0, unstable.NewParserError(b[i:i+1], "float can have at most one decimal point")
+				return 0, newDecodeError(b[i:i+1], "float can have at most one decimal point")
 			}
 			if !isDigit(cleaned[i-1]) {
-				return 0, unstable.NewParserError(b[i-1:i+1], "float decimal point must be preceded by a digit")
+				return 0, newDecodeError(b[i-1:i+1], "float decimal point must be preceded by a digit")
 			}
 			if !isDigit(cleaned[i+1]) {
-				return 0, unstable.NewParserError(b[i:i+2], "float decimal point must be followed by a digit")
+				return 0, newDecodeError(b[i:i+2], "float decimal point must be followed by a digit")
 			}
 			dotAlreadySeen = true
 		}
@@ -318,13 +316,13 @@ func parseFloat(b []byte) (float64, error) {
 	if cleaned[0] == '+' || cleaned[0] == '-' {
 		start = 1
 	}
-	if cleaned[start] == '0' && len(cleaned) > start+1 && isDigit(cleaned[start+1]) {
-		return 0, unstable.NewParserError(b, "float integer part cannot have leading zeroes")
+	if cleaned[start] == '0' && isDigit(cleaned[start+1]) {
+		return 0, newDecodeError(b, "float integer part cannot have leading zeroes")
 	}

 	f, err := strconv.ParseFloat(string(cleaned), 64)
 	if err != nil {
-		return 0, unstable.NewParserError(b, "unable to parse float: %w", err)
+		return 0, newDecodeError(b, "unable to parse float: %w", err)
 	}

 	return f, nil
@@ -338,7 +336,7 @@ func parseIntHex(b []byte) (int64, error) {

 	i, err := strconv.ParseInt(string(cleaned), 16, 64)
 	if err != nil {
-		return 0, unstable.NewParserError(b, "couldn't parse hexadecimal number: %w", err)
+		return 0, newDecodeError(b, "couldn't parse hexadecimal number: %w", err)
 	}

 	return i, nil
@@ -352,7 +350,7 @@ func parseIntOct(b []byte) (int64, error) {

 	i, err := strconv.ParseInt(string(cleaned), 8, 64)
 	if err != nil {
-		return 0, unstable.NewParserError(b, "couldn't parse octal number: %w", err)
+		return 0, newDecodeError(b, "couldn't parse octal number: %w", err)
 	}

 	return i, nil
@@ -366,7 +364,7 @@ func parseIntBin(b []byte) (int64, error) {

 	i, err := strconv.ParseInt(string(cleaned), 2, 64)
 	if err != nil {
-		return 0, unstable.NewParserError(b, "couldn't parse binary number: %w", err)
+		return 0, newDecodeError(b, "couldn't parse binary number: %w", err)
 	}

 	return i, nil
@@ -389,12 +387,12 @@ func parseIntDec(b []byte) (int64, error) {
 	}

 	if len(cleaned) > startIdx+1 && cleaned[startIdx] == '0' {
-		return 0, unstable.NewParserError(b, "leading zero not allowed on decimal number")
+		return 0, newDecodeError(b, "leading zero not allowed on decimal number")
 	}

 	i, err := strconv.ParseInt(string(cleaned), 10, 64)
 	if err != nil {
-		return 0, unstable.NewParserError(b, "couldn't parse decimal number: %w", err)
+		return 0, newDecodeError(b, "couldn't parse decimal number: %w", err)
 	}

 	return i, nil
@@ -411,11 +409,11 @@ func checkAndRemoveUnderscoresIntegers(b []byte) ([]byte, error) {
 	}

 	if b[start] == '_' {
-		return nil, unstable.NewParserError(b[start:start+1], "number cannot start with underscore")
+		return nil, newDecodeError(b[start:start+1], "number cannot start with underscore")
 	}

 	if b[len(b)-1] == '_' {
-		return nil, unstable.NewParserError(b[len(b)-1:], "number cannot end with underscore")
+		return nil, newDecodeError(b[len(b)-1:], "number cannot end with underscore")
 	}

 	// fast path
@@ -437,7 +435,7 @@ func checkAndRemoveUnderscoresIntegers(b []byte) ([]byte, error) {
 		c := b[i]
 		if c == '_' {
 			if !before {
-				return nil, unstable.NewParserError(b[i-1:i+1], "number must have at least one digit between underscores")
+				return nil, newDecodeError(b[i-1:i+1], "number must have at least one digit between underscores")
 			}
 			before = false
 		} else {
@@ -451,11 +449,11 @@ func checkAndRemoveUnderscoresIntegers(b []byte) ([]byte, error) {

 func checkAndRemoveUnderscoresFloats(b []byte) ([]byte, error) {
 	if b[0] == '_' {
-		return nil, unstable.NewParserError(b[0:1], "number cannot start with underscore")
+		return nil, newDecodeError(b[0:1], "number cannot start with underscore")
 	}

 	if b[len(b)-1] == '_' {
-		return nil, unstable.NewParserError(b[len(b)-1:], "number cannot end with underscore")
+		return nil, newDecodeError(b[len(b)-1:], "number cannot end with underscore")
 	}

 	// fast path
@@ -478,10 +476,10 @@ func checkAndRemoveUnderscoresFloats(b []byte) ([]byte, error) {
 		switch c {
 		case '_':
 			if !before {
-				return nil, unstable.NewParserError(b[i-1:i+1], "number must have at least one digit between underscores")
+				return nil, newDecodeError(b[i-1:i+1], "number must have at least one digit between underscores")
 			}
 			if i < len(b)-1 && (b[i+1] == 'e' || b[i+1] == 'E') {
-				return nil, unstable.NewParserError(b[i+1:i+2], "cannot have underscore before exponent")
+				return nil, newDecodeError(b[i+1:i+2], "cannot have underscore before exponent")
 			}
 			before = false
 		case '+', '-':
@@ -490,15 +488,15 @@ func checkAndRemoveUnderscoresFloats(b []byte) ([]byte, error) {
 			before = false
 		case 'e', 'E':
 			if i < len(b)-1 && b[i+1] == '_' {
-				return nil, unstable.NewParserError(b[i+1:i+2], "cannot have underscore after exponent")
+				return nil, newDecodeError(b[i+1:i+2], "cannot have underscore after exponent")
 			}
 			cleaned = append(cleaned, c)
 		case '.':
 			if i < len(b)-1 && b[i+1] == '_' {
-				return nil, unstable.NewParserError(b[i+1:i+2], "cannot have underscore after decimal point")
+				return nil, newDecodeError(b[i+1:i+2], "cannot have underscore after decimal point")
 			}
 			if i > 0 && b[i-1] == '_' {
-				return nil, unstable.NewParserError(b[i-1:i], "cannot have underscore before decimal point")
+				return nil, newDecodeError(b[i-1:i], "cannot have underscore before decimal point")
 			}
 			cleaned = append(cleaned, c)
 		default:
@@ -544,7 +542,3 @@ func daysIn(m int, year int) int {
 func isLeap(year int) bool {
 	return year%4 == 0 && (year%100 != 0 || year%400 == 0)
 }
-
-func isDigit(r byte) bool {
-	return r >= '0' && r <= '9'
-}
@@ -6,7 +6,6 @@ import (
 	"strings"

 	"github.com/pelletier/go-toml/v2/internal/danger"
-	"github.com/pelletier/go-toml/v2/unstable"
 )

 // DecodeError represents an error encountered during the parsing or decoding
@@ -56,6 +55,25 @@ func (s *StrictMissingError) String() string {

 type Key []string

+// internal version of DecodeError that is used as the base to create a
+// DecodeError with full context.
+type decodeError struct {
+	highlight []byte
+	message   string
+	key       Key // optional
+}
+
+func (de *decodeError) Error() string {
+	return de.message
+}
+
+func newDecodeError(highlight []byte, format string, args ...interface{}) error {
+	return &decodeError{
+		highlight: highlight,
+		message:   fmt.Errorf(format, args...).Error(),
+	}
+}
+
 // Error returns the error message contained in the DecodeError.
 func (e *DecodeError) Error() string {
 	return "toml: " + e.message
@@ -87,12 +105,12 @@ func (e *DecodeError) Key() Key {
 // highlight can be freely deallocated.
 //
 //nolint:funlen
-func wrapDecodeError(document []byte, de *unstable.ParserError) *DecodeError {
-	offset := danger.SubsliceOffset(document, de.Highlight)
+func wrapDecodeError(document []byte, de *decodeError) *DecodeError {
+	offset := danger.SubsliceOffset(document, de.highlight)

 	errMessage := de.Error()
 	errLine, errColumn := positionAtEnd(document[:offset])
-	before, after := linesOfContext(document, de.Highlight, offset, 3)
+	before, after := linesOfContext(document, de.highlight, offset, 3)

 	var buf strings.Builder

@@ -122,7 +140,7 @@ func wrapDecodeError(document []byte, de *unstable.ParserError) *DecodeError {
 		buf.Write(before[0])
 	}

-	buf.Write(de.Highlight)
+	buf.Write(de.highlight)

 	if len(after) > 0 {
 		buf.Write(after[0])
@@ -140,7 +158,7 @@ func wrapDecodeError(document []byte, de *unstable.ParserError) *DecodeError {
 		buf.WriteString(strings.Repeat(" ", len(before[0])))
 	}

-	buf.WriteString(strings.Repeat("~", len(de.Highlight)))
+	buf.WriteString(strings.Repeat("~", len(de.highlight)))

 	if len(errMessage) > 0 {
 		buf.WriteString(" ")
@@ -165,7 +183,7 @@ func wrapDecodeError(document []byte, de *unstable.ParserError) *DecodeError {
 		message: errMessage,
 		line:    errLine,
 		column:  errColumn,
-		key:     de.Key,
+		key:     de.key,
 		human:   buf.String(),
 	}
 }
@@ -7,7 +7,6 @@ import (
 	"strings"
 	"testing"

-	"github.com/pelletier/go-toml/v2/unstable"
 	"github.com/stretchr/testify/assert"
 )

@@ -171,9 +170,9 @@ line 5`,
 			doc := b.Bytes()
 			hl := doc[start:end]

-			err := wrapDecodeError(doc, &unstable.ParserError{
-				Highlight: hl,
-				Message:   e.msg,
+			err := wrapDecodeError(doc, &decodeError{
+				highlight: hl,
+				message:   e.msg,
 			})

 			var derr *DecodeError
@@ -1,37 +0,0 @@
-package toml_test
-
-import (
-	"fmt"
-	"log"
-	"strconv"
-
-	"github.com/pelletier/go-toml/v2"
-)
-
-type customInt int
-
-func (i *customInt) UnmarshalText(b []byte) error {
-	x, err := strconv.ParseInt(string(b), 10, 32)
-	if err != nil {
-		return err
-	}
-	*i = customInt(x * 100)
-	return nil
-}
-
-type doc struct {
-	Value customInt
-}
-
-func ExampleUnmarshal_textUnmarshal() {
-	var x doc
-
-	data := []byte(`value  = "42"`)
-	err := toml.Unmarshal(data, &x)
-	if err != nil {
-		log.Fatal(err)
-	}
-	fmt.Println(x)
-	// Output:
-	// {4200}
-}
@@ -7,20 +7,13 @@ import (
 	"github.com/stretchr/testify/require"
 )

-func TestFastSimpleInt(t *testing.T) {
+func TestFastSimple(t *testing.T) {
 	m := map[string]int64{}
 	err := toml.Unmarshal([]byte(`a = 42`), &m)
 	require.NoError(t, err)
 	require.Equal(t, map[string]int64{"a": 42}, m)
 }

-func TestFastSimpleFloat(t *testing.T) {
-	m := map[string]float64{}
-	err := toml.Unmarshal([]byte("a = 42\nb = 1.1\nc = 12341234123412341234123412341234"), &m)
-	require.NoError(t, err)
-	require.Equal(t, map[string]float64{"a": 42, "b": 1.1, "c": 1.2341234123412342e+31}, m)
-}
-
 func TestFastSimpleString(t *testing.T) {
 	m := map[string]string{}
 	err := toml.Unmarshal([]byte(`a = "hello"`), &m)
@@ -1,5 +1,5 @@
-//go:build go1.18 || go1.19 || go1.20 || go1.21
-// +build go1.18 go1.19 go1.20 go1.21
+//go:build go1.18 || go1.19
+// +build go1.18 go1.19

 package toml_test

@@ -2,4 +2,4 @@ module github.com/pelletier/go-toml/v2

 go 1.16

-require github.com/stretchr/testify v1.8.4
+require github.com/stretchr/testify v1.8.0
@@ -5,11 +5,9 @@ github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZb
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/objx v0.4.0/go.mod h1:YvHI0jy2hoMjB+UWwv71VJQ9isScKT/TqJzVSSt89Yw=
-github.com/stretchr/objx v0.5.0/go.mod h1:Yh+to48EsGEfYuaHDzXPcE3xhTkx73EhmCGUpEOglKo=
 github.com/stretchr/testify v1.7.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+github.com/stretchr/testify v1.8.0 h1:pSgiaMZlXftHpm5L7V1+rVB+AZJydKsMxsQBIJw4PKk=
 github.com/stretchr/testify v1.8.0/go.mod h1:yNjHg4UonilssWZ8iaSj1OCr/vHnekPRkoO+kdMU+MU=
-github.com/stretchr/testify v1.8.4 h1:CcVxjf3Q8PM0mHUKJCdn+eZZtm5yQwehR5yeSVQQcUk=
-github.com/stretchr/testify v1.8.4/go.mod h1:sz/lmYIOXD/1dqDmKjjqLyZ2RngseejIcXlSw2iwfAo=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
@@ -1,4 +1,4 @@
-package unstable
+package ast

 import (
 	"fmt"
@@ -7,16 +7,13 @@ import (
 	"github.com/pelletier/go-toml/v2/internal/danger"
 )

-// Iterator over a sequence of nodes.
-//
-// Starts uninitialized, you need to call Next() first.
+// Iterator starts uninitialized, you need to call Next() first.
 //
 // For example:
 //
 //	it := n.Children()
 //	for it.Next() {
-//		n := it.Node()
-//		// do something with n
+//			it.Node()
 //	}
 type Iterator struct {
 	started bool
@@ -35,31 +32,42 @@ func (c *Iterator) Next() bool {
 }

 // IsLast returns true if the current node of the iterator is the last
-// one.  Subsequent calls to Next() will return false.
+// one.  Subsequent call to Next() will return false.
 func (c *Iterator) IsLast() bool {
 	return c.node.next == 0
 }

-// Node returns a pointer to the node pointed at by the iterator.
+// Node returns a copy of the node pointed at by the iterator.
 func (c *Iterator) Node() *Node {
 	return c.node
 }

-// Node in a TOML expression AST.
+// Root contains a full AST.
 //
-// Depending on Kind, its sequence of children should be interpreted
-// differently.
-//
-//   - Array have one child per element in the array.
-//   - InlineTable have one child per key-value in the table (each of kind
-//     InlineTable).
-//   - KeyValue have at least two children. The first one is the value. The rest
-//     make a potentially dotted key.
-//   - Table and ArrayTable's children represent a dotted key (same as
-//     KeyValue, but without the first node being the value).
-//
-// When relevant, Raw describes the range of bytes this node is referring to in
-// the input document. Use Parser.Raw() to retrieve the actual bytes.
+// It is immutable once constructed with Builder.
+type Root struct {
+	nodes []Node
+}
+
+// Iterator over the top level nodes.
+func (r *Root) Iterator() Iterator {
+	it := Iterator{}
+	if len(r.nodes) > 0 {
+		it.node = &r.nodes[0]
+	}
+	return it
+}
+
+func (r *Root) at(idx Reference) *Node {
+	return &r.nodes[idx]
+}
+
+// Arrays have one child per element in the array.  InlineTables have
+// one child per key-value pair in the table.  KeyValues have at least
+// two children. The first one is the value. The rest make a
+// potentially dotted key.  Table and Array table have one child per
+// element of the key they represent (same as KeyValue, but without
+// the last node being the value).
 type Node struct {
 	Kind Kind
 	Raw  Range  // Raw bytes from the input.
@@ -72,13 +80,13 @@ type Node struct {
 	child int // 0 if no child
 }

-// Range of bytes in the document.
 type Range struct {
 	Offset uint32
 	Length uint32
 }

-// Next returns a pointer to the next node, or nil if there is no next node.
+// Next returns a copy of the next node, or an invalid Node if there
+// is no next node.
 func (n *Node) Next() *Node {
 	if n.next == 0 {
 		return nil
@@ -88,9 +96,9 @@ func (n *Node) Next() *Node {
 	return (*Node)(danger.Stride(ptr, size, n.next))
 }

-// Child returns a pointer to the first child node of this node. Other children
-// can be accessed calling Next on the first child.  Returns an nil if this Node
-// has no child.
+// Child returns a copy of the first child node of this node. Other
+// children can be accessed calling Next on the first child.  Returns
+// an invalid Node if there is none.
 func (n *Node) Child() *Node {
 	if n.child == 0 {
 		return nil
@@ -105,9 +113,9 @@ func (n *Node) Valid() bool {
 	return n != nil
 }

-// Key returns the children nodes making the Key on a supported node. Panics
-// otherwise.  They are guaranteed to be all be of the Kind Key. A simple key
-// would return just one element.
+// Key returns the child nodes making the Key on a supported
+// node. Panics otherwise.  They are guaranteed to be all be of the
+// Kind Key. A simple key would return just one element.
 func (n *Node) Key() Iterator {
 	switch n.Kind {
 	case KeyValue:
@@ -0,0 +1,51 @@
+package ast
+
+type Reference int
+
+const InvalidReference Reference = -1
+
+func (r Reference) Valid() bool {
+	return r != InvalidReference
+}
+
+type Builder struct {
+	tree    Root
+	lastIdx int
+}
+
+func (b *Builder) Tree() *Root {
+	return &b.tree
+}
+
+func (b *Builder) NodeAt(ref Reference) *Node {
+	return b.tree.at(ref)
+}
+
+func (b *Builder) Reset() {
+	b.tree.nodes = b.tree.nodes[:0]
+	b.lastIdx = 0
+}
+
+func (b *Builder) Push(n Node) Reference {
+	b.lastIdx = len(b.tree.nodes)
+	b.tree.nodes = append(b.tree.nodes, n)
+	return Reference(b.lastIdx)
+}
+
+func (b *Builder) PushAndChain(n Node) Reference {
+	newIdx := len(b.tree.nodes)
+	b.tree.nodes = append(b.tree.nodes, n)
+	if b.lastIdx >= 0 {
+		b.tree.nodes[b.lastIdx].next = newIdx - b.lastIdx
+	}
+	b.lastIdx = newIdx
+	return Reference(b.lastIdx)
+}
+
+func (b *Builder) AttachChild(parent Reference, child Reference) {
+	b.tree.nodes[parent].child = int(child) - int(parent)
+}
+
+func (b *Builder) Chain(from Reference, to Reference) {
+	b.tree.nodes[from].next = int(to) - int(from)
+}
@@ -1,26 +1,25 @@
-package unstable
+package ast

 import "fmt"

-// Kind represents the type of TOML structure contained in a given Node.
 type Kind int

 const (
-	// Meta
+	// meta
 	Invalid Kind = iota
 	Comment
 	Key

-	// Top level structures
+	// top level structures
 	Table
 	ArrayTable
 	KeyValue

-	// Containers values
+	// containers values
 	Array
 	InlineTable

-	// Values
+	// values
 	String
 	Bool
 	Float
@@ -31,7 +30,6 @@ const (
 	DateTime
 )

-// String implementation of fmt.Stringer.
 func (k Kind) String() string {
 	switch k {
 	case Invalid:
@@ -1,42 +0,0 @@
-package characters
-
-var invalidAsciiTable = [256]bool{
-	0x00: true,
-	0x01: true,
-	0x02: true,
-	0x03: true,
-	0x04: true,
-	0x05: true,
-	0x06: true,
-	0x07: true,
-	0x08: true,
-	// 0x09 TAB
-	// 0x0A LF
-	0x0B: true,
-	0x0C: true,
-	// 0x0D CR
-	0x0E: true,
-	0x0F: true,
-	0x10: true,
-	0x11: true,
-	0x12: true,
-	0x13: true,
-	0x14: true,
-	0x15: true,
-	0x16: true,
-	0x17: true,
-	0x18: true,
-	0x19: true,
-	0x1A: true,
-	0x1B: true,
-	0x1C: true,
-	0x1D: true,
-	0x1E: true,
-	0x1F: true,
-	// 0x20 - 0x7E Printable ASCII characters
-	0x7F: true,
-}
-
-func InvalidAscii(b byte) bool {
-	return invalidAsciiTable[b]
-}
@@ -18,7 +18,7 @@ type Program struct {
 	Usage string
 	Fn    ConvertFn
 	// Inplace allows the command to take more than one file as argument and
-	// perform conversion in place on each provided file.
+	// perform convertion in place on each provided file.
 	Inplace bool
 }

@@ -1085,6 +1085,10 @@ func TestUnmarshalCheckConversionFloatInt(t *testing.T) {
 			desc:  "int",
 			input: `I = 1e300`,
 		},
+		{
+			desc:  "float",
+			input: `F = 9223372036854775806`,
+		},
 	}

 	for _, test := range testCases {
@@ -4,8 +4,6 @@ import (
 	"fmt"
 	"strconv"
 	"time"
-
-	"github.com/pelletier/go-toml/v2"
 )

 // Remove JSON tags to a data structure as returned by toml-test.
@@ -78,31 +76,14 @@ func untag(typed map[string]interface{}) (interface{}, error) {
 			return nil, fmt.Errorf("untag: %w", err)
 		}
 		return f, nil
-
-		//toml.LocalDate{Year:2020, Month:12, Day:12}
 	case "datetime":
-		return time.Parse("2006-01-02T15:04:05.999999999Z07:00", v)
+		return parseTime(v, "2006-01-02T15:04:05.999999999Z07:00", false)
 	case "datetime-local":
-		var t toml.LocalDateTime
-		err := t.UnmarshalText([]byte(v))
-		if err != nil {
-			return nil, fmt.Errorf("untag: %w", err)
-		}
-		return t, nil
+		return parseTime(v, "2006-01-02T15:04:05.999999999", true)
 	case "date-local":
-		var t toml.LocalDate
-		err := t.UnmarshalText([]byte(v))
-		if err != nil {
-			return nil, fmt.Errorf("untag: %w", err)
-		}
-		return t, nil
+		return parseTime(v, "2006-01-02", true)
 	case "time-local":
-		var t toml.LocalTime
-		err := t.UnmarshalText([]byte(v))
-		if err != nil {
-			return nil, fmt.Errorf("untag: %w", err)
-		}
-		return t, nil
+		return parseTime(v, "15:04:05.999999999", true)
 	case "bool":
 		switch v {
 		case "true":
@@ -48,21 +48,3 @@ func DecodeStdin() error {

 	return nil
 }
-
-// EncodeStdin is a helper function for the toml-test binary interface.  Tagged
-// JSON is read from STDIN and a resulting TOML representation is written to
-// STDOUT.
-func EncodeStdin() error {
-	var j interface{}
-	err := json.NewDecoder(os.Stdin).Decode(&j)
-	if err != nil {
-		return err
-	}
-
-	rm, err := rmTag(j)
-	if err != nil {
-		return fmt.Errorf("removing tags: %w", err)
-	}
-
-	return toml.NewEncoder(os.Stdout).Encode(rm)
-}
@@ -1,6 +1,8 @@
 package tracker

-import "github.com/pelletier/go-toml/v2/unstable"
+import (
+	"github.com/pelletier/go-toml/v2/internal/ast"
+)

 // KeyTracker is a tracker that keeps track of the current Key as the AST is
 // walked.
@@ -9,19 +11,19 @@ type KeyTracker struct {
 }

 // UpdateTable sets the state of the tracker with the AST table node.
-func (t *KeyTracker) UpdateTable(node *unstable.Node) {
+func (t *KeyTracker) UpdateTable(node *ast.Node) {
 	t.reset()
 	t.Push(node)
 }

 // UpdateArrayTable sets the state of the tracker with the AST array table node.
-func (t *KeyTracker) UpdateArrayTable(node *unstable.Node) {
+func (t *KeyTracker) UpdateArrayTable(node *ast.Node) {
 	t.reset()
 	t.Push(node)
 }

 // Push the given key on the stack.
-func (t *KeyTracker) Push(node *unstable.Node) {
+func (t *KeyTracker) Push(node *ast.Node) {
 	it := node.Key()
 	for it.Next() {
 		t.k = append(t.k, string(it.Node().Data))
@@ -29,7 +31,7 @@ func (t *KeyTracker) Push(node *unstable.Node) {
 }

 // Pop key from stack.
-func (t *KeyTracker) Pop(node *unstable.Node) {
+func (t *KeyTracker) Pop(node *ast.Node) {
 	it := node.Key()
 	for it.Next() {
 		t.k = t.k[:len(t.k)-1]
@@ -5,7 +5,7 @@ import (
 	"fmt"
 	"sync"

-	"github.com/pelletier/go-toml/v2/unstable"
+	"github.com/pelletier/go-toml/v2/internal/ast"
 )

 type keyKind uint8
@@ -150,23 +150,23 @@ func (s *SeenTracker) setExplicitFlag(parentIdx int) {
 // CheckExpression takes a top-level node and checks that it does not contain
 // keys that have been seen in previous calls, and validates that types are
 // consistent.
-func (s *SeenTracker) CheckExpression(node *unstable.Node) error {
+func (s *SeenTracker) CheckExpression(node *ast.Node) error {
 	if s.entries == nil {
 		s.reset()
 	}
 	switch node.Kind {
-	case unstable.KeyValue:
+	case ast.KeyValue:
 		return s.checkKeyValue(node)
-	case unstable.Table:
+	case ast.Table:
 		return s.checkTable(node)
-	case unstable.ArrayTable:
+	case ast.ArrayTable:
 		return s.checkArrayTable(node)
 	default:
 		panic(fmt.Errorf("this should not be a top level node type: %s", node.Kind))
 	}
 }

-func (s *SeenTracker) checkTable(node *unstable.Node) error {
+func (s *SeenTracker) checkTable(node *ast.Node) error {
 	if s.currentIdx >= 0 {
 		s.setExplicitFlag(s.currentIdx)
 	}
@@ -219,7 +219,7 @@ func (s *SeenTracker) checkTable(node *unstable.Node) error {
 	return nil
 }

-func (s *SeenTracker) checkArrayTable(node *unstable.Node) error {
+func (s *SeenTracker) checkArrayTable(node *ast.Node) error {
 	if s.currentIdx >= 0 {
 		s.setExplicitFlag(s.currentIdx)
 	}
@@ -267,7 +267,7 @@ func (s *SeenTracker) checkArrayTable(node *unstable.Node) error {
 	return nil
 }

-func (s *SeenTracker) checkKeyValue(node *unstable.Node) error {
+func (s *SeenTracker) checkKeyValue(node *ast.Node) error {
 	parentIdx := s.currentIdx
 	it := node.Key()

@@ -297,26 +297,26 @@ func (s *SeenTracker) checkKeyValue(node *unstable.Node) error {
 	value := node.Value()

 	switch value.Kind {
-	case unstable.InlineTable:
+	case ast.InlineTable:
 		return s.checkInlineTable(value)
-	case unstable.Array:
+	case ast.Array:
 		return s.checkArray(value)
 	}

 	return nil
 }

-func (s *SeenTracker) checkArray(node *unstable.Node) error {
+func (s *SeenTracker) checkArray(node *ast.Node) error {
 	it := node.Children()
 	for it.Next() {
 		n := it.Node()
 		switch n.Kind {
-		case unstable.InlineTable:
+		case ast.InlineTable:
 			err := s.checkInlineTable(n)
 			if err != nil {
 				return err
 			}
-		case unstable.Array:
+		case ast.Array:
 			err := s.checkArray(n)
 			if err != nil {
 				return err
@@ -326,7 +326,7 @@ func (s *SeenTracker) checkArray(node *unstable.Node) error {
 	return nil
 }

-func (s *SeenTracker) checkInlineTable(node *unstable.Node) error {
+func (s *SeenTracker) checkInlineTable(node *ast.Node) error {
 	if pool.New == nil {
 		pool.New = func() interface{} {
 			return &SeenTracker{}
@@ -4,8 +4,6 @@ import (
 	"fmt"
 	"strings"
 	"time"
-
-	"github.com/pelletier/go-toml/v2/unstable"
 )

 // LocalDate represents a calendar day in no specific timezone.
@@ -77,7 +75,7 @@ func (d LocalTime) MarshalText() ([]byte, error) {
 func (d *LocalTime) UnmarshalText(b []byte) error {
 	res, left, err := parseLocalTime(b)
 	if err == nil && len(left) != 0 {
-		err = unstable.NewParserError(left, "extra characters")
+		err = newDecodeError(left, "extra characters")
 	}
 	if err != nil {
 		return err
@@ -111,7 +109,7 @@ func (d LocalDateTime) MarshalText() ([]byte, error) {
 func (d *LocalDateTime) UnmarshalText(data []byte) error {
 	res, left, err := parseLocalDateTime(data)
 	if err == nil && len(left) != 0 {
-		err = unstable.NewParserError(left, "extra characters")
+		err = newDecodeError(left, "extra characters")
 	}
 	if err != nil {
 		return err
@@ -12,8 +12,6 @@ import (
 	"strings"
 	"time"
 	"unicode"
-
-	"github.com/pelletier/go-toml/v2/internal/characters"
 )

 // Marshal serializes a Go value as a TOML document.
@@ -148,9 +146,6 @@ func (enc *Encoder) SetIndentTables(indent bool) *Encoder {
 //
 // The "omitempty" option prevents empty values or groups from being emitted.
 //
-// The "commented" option prefixes the value and all its children with a comment
-// symbol.
-//
 // In addition to the "toml" tag struct tag, a "comment" tag can be used to emit
 // a TOML comment before the value being annotated. Comments are ignored inside
 // inline tables. For array tables, the comment is only present before the first
@@ -183,7 +178,6 @@ func (enc *Encoder) Encode(v interface{}) error {
 type valueOptions struct {
 	multiline bool
 	omitempty bool
-	commented bool
 	comment   string
 }

@@ -209,9 +203,6 @@ type encoderCtx struct {
 	// Indentation level
 	indent int

-	// Prefix the current value with a comment.
-	commented bool
-
 	// Options coming from struct tags
 	options valueOptions
 }
@@ -280,7 +271,7 @@ func (enc *Encoder) encode(b []byte, ctx encoderCtx, v reflect.Value) ([]byte, e
 		return enc.encodeMap(b, ctx, v)
 	case reflect.Struct:
 		return enc.encodeStruct(b, ctx, v)
-	case reflect.Slice, reflect.Array:
+	case reflect.Slice:
 		return enc.encodeSlice(b, ctx, v)
 	case reflect.Interface:
 		if v.IsNil() {
@@ -364,10 +355,9 @@ func (enc *Encoder) encodeKv(b []byte, ctx encoderCtx, options valueOptions, v r

 	if !ctx.inline {
 		b = enc.encodeComment(ctx.indent, options.comment, b)
-		b = enc.commented(ctx.commented, b)
-		b = enc.indent(ctx.indent, b)
 	}

+	b = enc.indent(ctx.indent, b)
 	b = enc.encodeKey(b, ctx.key)
 	b = append(b, " = "...)

@@ -386,13 +376,6 @@ func (enc *Encoder) encodeKv(b []byte, ctx encoderCtx, options valueOptions, v r
 	return b, nil
 }

-func (enc *Encoder) commented(commented bool, b []byte) []byte {
-	if commented {
-		return append(b, "# "...)
-	}
-	return b
-}
-
 func isEmptyValue(v reflect.Value) bool {
 	switch v.Kind() {
 	case reflect.Struct:
@@ -454,7 +437,7 @@ func (enc *Encoder) encodeString(b []byte, v string, options valueOptions) []byt
 func needsQuoting(v string) bool {
 	// TODO: vectorize
 	for _, b := range []byte(v) {
-		if b == '\'' || b == '\r' || b == '\n' || characters.InvalidAscii(b) {
+		if b == '\'' || b == '\r' || b == '\n' || invalidAscii(b) {
 			return true
 		}
 	}
@@ -541,8 +524,6 @@ func (enc *Encoder) encodeTableHeader(ctx encoderCtx, b []byte) ([]byte, error)

 	b = enc.encodeComment(ctx.indent, ctx.options.comment, b)

-	b = enc.commented(ctx.commented, b)
-
 	b = enc.indent(ctx.indent, b)

 	b = append(b, '[')
@@ -594,23 +575,11 @@ func (enc *Encoder) encodeKey(b []byte, k string) []byte {
 	}
 }

-func (enc *Encoder) keyToString(k reflect.Value) (string, error) {
-	keyType := k.Type()
-	switch {
-	case keyType.Kind() == reflect.String:
-		return k.String(), nil
-
-	case keyType.Implements(textMarshalerType):
-		keyB, err := k.Interface().(encoding.TextMarshaler).MarshalText()
-		if err != nil {
-			return "", fmt.Errorf("toml: error marshalling key %v from text: %w", k, err)
-		}
-		return string(keyB), nil
-	}
-	return "", fmt.Errorf("toml: type %s is not supported as a map key", keyType.Kind())
-}
-
 func (enc *Encoder) encodeMap(b []byte, ctx encoderCtx, v reflect.Value) ([]byte, error) {
+	if v.Type().Key().Kind() != reflect.String {
+		return nil, fmt.Errorf("toml: type %s is not supported as a map key", v.Type().Key().Kind())
+	}
+
 	var (
 		t                 table
 		emptyValueOptions valueOptions
@@ -618,17 +587,13 @@ func (enc *Encoder) encodeMap(b []byte, ctx encoderCtx, v reflect.Value) ([]byte

 	iter := v.MapRange()
 	for iter.Next() {
+		k := iter.Key().String()
 		v := iter.Value()

 		if isNil(v) {
 			continue
 		}

-		k, err := enc.keyToString(iter.Key())
-		if err != nil {
-			return nil, err
-		}
-
 		if willConvertToTableOrArrayTable(ctx, v) {
 			t.pushTable(k, v, emptyValueOptions)
 		} else {
@@ -721,7 +686,6 @@ func walkStruct(ctx encoderCtx, t *table, v reflect.Value) {
 		options := valueOptions{
 			multiline: opts.multiline,
 			omitempty: opts.omitempty,
-			commented: opts.commented,
 			comment:   fieldType.Tag.Get("comment"),
 		}

@@ -781,7 +745,6 @@ type tagOptions struct {
 	multiline bool
 	inline    bool
 	omitempty bool
-	commented bool
 }

 func parseTag(tag string) (string, tagOptions) {
@@ -809,8 +772,6 @@ func parseTag(tag string) (string, tagOptions) {
 			opts.inline = true
 		case "omitempty":
 			opts.omitempty = true
-		case "commented":
-			opts.commented = true
 		}
 	}

@@ -846,10 +807,8 @@ func (enc *Encoder) encodeTable(b []byte, ctx encoderCtx, t table) ([]byte, erro
 		hasNonEmptyKV = true

 		ctx.setKey(kv.Key)
-		ctx2 := ctx
-		ctx2.commented = kv.Options.commented || ctx2.commented

-		b, err = enc.encodeKv(b, ctx2, kv.Options, kv.Value)
+		b, err = enc.encodeKv(b, ctx, kv.Options, kv.Value)
 		if err != nil {
 			return nil, err
 		}
@@ -874,10 +833,8 @@ func (enc *Encoder) encodeTable(b []byte, ctx encoderCtx, t table) ([]byte, erro
 		ctx.setKey(table.Key)

 		ctx.options = table.Options
-		ctx2 := ctx
-		ctx2.commented = ctx2.commented || ctx.options.commented

-		b, err = enc.encode(b, ctx2, table.Value)
+		b, err = enc.encode(b, ctx, table.Value)
 		if err != nil {
 			return nil, err
 		}
@@ -955,7 +912,7 @@ func willConvertToTableOrArrayTable(ctx encoderCtx, v reflect.Value) bool {
 		return willConvertToTableOrArrayTable(ctx, v.Elem())
 	}

-	if t.Kind() == reflect.Slice || t.Kind() == reflect.Array {
+	if t.Kind() == reflect.Slice {
 		if v.Len() == 0 {
 			// An empty slice should be a kv = [].
 			return false
@@ -995,9 +952,6 @@ func (enc *Encoder) encodeSliceAsArrayTable(b []byte, ctx encoderCtx, v reflect.
 	ctx.shiftKey()

 	scratch := make([]byte, 0, 64)
-
-	scratch = enc.commented(ctx.commented, scratch)
-
 	scratch = append(scratch, "[["...)

 	for i, k := range ctx.parentKey {
@@ -1013,10 +967,6 @@ func (enc *Encoder) encodeSliceAsArrayTable(b []byte, ctx encoderCtx, v reflect.

 	b = enc.encodeComment(ctx.indent, ctx.options.comment, b)

-	if enc.indentTables {
-		ctx.indent++
-	}
-
 	for i := 0; i < v.Len(); i++ {
 		if i != 0 {
 			b = append(b, "\n"...)
@@ -15,21 +15,6 @@ import (
 	"github.com/stretchr/testify/require"
 )

-type marshalTextKey struct {
-	A string
-	B string
-}
-
-func (k marshalTextKey) MarshalText() ([]byte, error) {
-	return []byte(k.A + "-" + k.B), nil
-}
-
-type marshalBadTextKey struct{}
-
-func (k marshalBadTextKey) MarshalText() ([]byte, error) {
-	return nil, fmt.Errorf("error")
-}
-
 func TestMarshal(t *testing.T) {
 	someInt := 42

@@ -112,53 +97,6 @@ also = 'that'
 a = 'test'
 `,
 		},
-		{
-			desc: `map with text key`,
-			v: map[marshalTextKey]string{
-				{A: "a", B: "1"}: "value 1",
-				{A: "a", B: "2"}: "value 2",
-				{A: "b", B: "1"}: "value 3",
-			},
-			expected: `a-1 = 'value 1'
-a-2 = 'value 2'
-b-1 = 'value 3'
-`,
-		},
-		{
-			desc: `table with text key`,
-			v: map[marshalTextKey]map[string]string{
-				{A: "a", B: "1"}: {"value": "foo"},
-			},
-			expected: `[a-1]
-value = 'foo'
-`,
-		},
-		{
-			desc: `map with ptr text key`,
-			v: map[*marshalTextKey]string{
-				{A: "a", B: "1"}: "value 1",
-				{A: "a", B: "2"}: "value 2",
-				{A: "b", B: "1"}: "value 3",
-			},
-			expected: `a-1 = 'value 1'
-a-2 = 'value 2'
-b-1 = 'value 3'
-`,
-		},
-		{
-			desc: `map with bad text key`,
-			v: map[marshalBadTextKey]string{
-				{}: "value 1",
-			},
-			err: true,
-		},
-		{
-			desc: `map with bad ptr text key`,
-			v: map[*marshalBadTextKey]string{
-				{}: "value 1",
-			},
-			err: true,
-		},
 		{
 			desc: "simple string array",
 			v: map[string][]string{
@@ -206,45 +144,6 @@ b-1 = 'value 3'

 [[top]]
 'map2.1' = 'v2.1'
-`,
-		},
-		{
-			desc: "fixed size string array",
-			v: map[string][3]string{
-				"array": {"one", "two", "three"},
-			},
-			expected: `array = ['one', 'two', 'three']
-`,
-		},
-		{
-			desc: "fixed size nested string arrays",
-			v: map[string][2][2]string{
-				"array": {{"one", "two"}, {"three"}},
-			},
-			expected: `array = [['one', 'two'], ['three', '']]
-`,
-		},
-		{
-			desc: "mixed strings and fixed size nested string arrays",
-			v: map[string][]interface{}{
-				"array": {"a string", [2]string{"one", "two"}, "last"},
-			},
-			expected: `array = ['a string', ['one', 'two'], 'last']
-`,
-		},
-		{
-			desc: "fixed size array of maps",
-			v: map[string][2]map[string]string{
-				"ftop": {
-					{"map1.1": "v1.1"},
-					{"map2.1": "v2.1"},
-				},
-			},
-			expected: `[[ftop]]
-'map1.1' = 'v1.1'
-
-[[ftop]]
-'map2.1' = 'v2.1'
 `,
 		},
 		{
@@ -588,13 +487,8 @@ foo = 42
 		},
 		{
 			desc: "invalid map key",
-			v:    map[int]interface{}{1: "a"},
-			err:  true,
-		},
-		{
-			desc:     "invalid map key but empty",
 			v:    map[int]interface{}{},
-			expected: "",
+			err:  true,
 		},
 		{
 			desc: "unhandled type",
@@ -1201,45 +1095,6 @@ randomize = true
 	require.Equal(t, expected, buf.String())
 }

-func TestMarhsalIssue888(t *testing.T) {
-	type Thing struct {
-		FieldA string `comment:"my field A"`
-		FieldB string `comment:"my field B"`
-	}
-
-	type Cfg struct {
-		Custom []Thing `comment:"custom config"`
-	}
-
-	buf := new(bytes.Buffer)
-
-	config := Cfg{
-		Custom: []Thing{
-			{FieldA: "field a 1", FieldB: "field b 1"},
-			{FieldA: "field a 2", FieldB: "field b 2"},
-		},
-	}
-
-	encoder := toml.NewEncoder(buf).SetIndentTables(true)
-	encoder.Encode(config)
-
-	expected := `# custom config
-[[Custom]]
-  # my field A
-  FieldA = 'field a 1'
-  # my field B
-  FieldB = 'field b 1'
-
-[[Custom]]
-  # my field A
-  FieldA = 'field a 2'
-  # my field B
-  FieldB = 'field b 2'
-`
-
-	require.Equal(t, expected, buf.String())
-}
-
 func TestMarshalNestedAnonymousStructs(t *testing.T) {
 	type Embedded struct {
 		Value string `toml:"value" json:"value"`
@@ -1335,115 +1190,6 @@ func TestMarshalUint64Overflow(t *testing.T) {
 	require.Error(t, err)
 }

-func TestIndentWithInlineTable(t *testing.T) {
-	x := map[string][]map[string]string{
-		"one": {
-			{"0": "0"},
-			{"1": "1"},
-		},
-	}
-	expected := `one = [
-  {0 = '0'},
-  {1 = '1'}
-]
-`
-	var buf bytes.Buffer
-	enc := toml.NewEncoder(&buf)
-	enc.SetIndentTables(true)
-	enc.SetTablesInline(true)
-	enc.SetArraysMultiline(true)
-	require.NoError(t, enc.Encode(x))
-	assert.Equal(t, expected, buf.String())
-}
-
-type C3 struct {
-	Value  int   `toml:",commented"`
-	Values []int `toml:",commented"`
-}
-
-type C2 struct {
-	Int       int64
-	String    string
-	ArrayInts []int
-	Structs   []C3
-}
-
-type C1 struct {
-	Int       int64  `toml:",commented"`
-	String    string `toml:",commented"`
-	ArrayInts []int  `toml:",commented"`
-	Structs   []C3   `toml:",commented"`
-}
-
-type Commented struct {
-	Int    int64  `toml:",commented"`
-	String string `toml:",commented"`
-
-	C1 C1
-	C2 C2 `toml:",commented"` // same as C1, but commented at top level
-}
-
-func TestMarshalCommented(t *testing.T) {
-	c := Commented{
-		Int:    42,
-		String: "root",
-
-		C1: C1{
-			Int:       11,
-			String:    "C1",
-			ArrayInts: []int{1, 2, 3},
-			Structs: []C3{
-				{Value: 100},
-				{Values: []int{4, 5, 6}},
-			},
-		},
-		C2: C2{
-			Int:       22,
-			String:    "C2",
-			ArrayInts: []int{1, 2, 3},
-			Structs: []C3{
-				{Value: 100},
-				{Values: []int{4, 5, 6}},
-			},
-		},
-	}
-
-	out, err := toml.Marshal(c)
-	require.NoError(t, err)
-
-	expected := `# Int = 42
-# String = 'root'
-
-[C1]
-# Int = 11
-# String = 'C1'
-# ArrayInts = [1, 2, 3]
-
-# [[C1.Structs]]
-# Value = 100
-# Values = []
-
-# [[C1.Structs]]
-# Value = 0
-# Values = [4, 5, 6]
-
-# [C2]
-# Int = 22
-# String = 'C2'
-# ArrayInts = [1, 2, 3]
-
-# [[C2.Structs]]
-# Value = 100
-# Values = []
-
-# [[C2.Structs]]
-# Value = 0
-# Values = [4, 5, 6]
-`
-
-	require.Equal(t, expected, string(out))
-}
-
 func ExampleMarshal() {
 	type MyConfig struct {
 		Version int
@@ -1468,161 +1214,3 @@ func ExampleMarshal() {
 	// Name = 'go-toml'
 	// Tags = ['go', 'toml']
 }
-
-// Example that uses the 'commented' field tag option to generate an example
-// configuration file that has commented out sections (example from
-// go-graphite/graphite-clickhouse).
-func ExampleMarshal_commented() {
-
-	type Common struct {
-		Listen               string        `toml:"listen"                     comment:"general listener"`
-		PprofListen          string        `toml:"pprof-listen"               comment:"listener to serve /debug/pprof requests. '-pprof' argument overrides it"`
-		MaxMetricsPerTarget  int           `toml:"max-metrics-per-target"     comment:"limit numbers of queried metrics per target in /render requests, 0 or negative = unlimited"`
-		MemoryReturnInterval time.Duration `toml:"memory-return-interval"     comment:"daemon will return the freed memory to the OS when it>0"`
-	}
-
-	type Costs struct {
-		Cost       *int           `toml:"cost"        comment:"default cost (for wildcarded equalence or matched with regex, or if no value cost set)"`
-		ValuesCost map[string]int `toml:"values-cost" comment:"cost with some value (for equalence without wildcards) (additional tuning, usually not needed)"`
-	}
-
-	type ClickHouse struct {
-		URL string `toml:"url" comment:"default url, see https://clickhouse.tech/docs/en/interfaces/http. Can be overwritten with query-params"`
-
-		RenderMaxQueries        int               `toml:"render-max-queries" comment:"Max queries to render queiries"`
-		RenderConcurrentQueries int               `toml:"render-concurrent-queries" comment:"Concurrent queries to render queiries"`
-		TaggedCosts             map[string]*Costs `toml:"tagged-costs,commented"`
-		TreeTable               string            `toml:"tree-table,commented"`
-		ReverseTreeTable        string            `toml:"reverse-tree-table,commented"`
-		DateTreeTable           string            `toml:"date-tree-table,commented"`
-		DateTreeTableVersion    int               `toml:"date-tree-table-version,commented"`
-		TreeTimeout             time.Duration     `toml:"tree-timeout,commented"`
-		TagTable                string            `toml:"tag-table,commented"`
-		ExtraPrefix             string            `toml:"extra-prefix"             comment:"add extra prefix (directory in graphite) for all metrics, w/o trailing dot"`
-		ConnectTimeout          time.Duration     `toml:"connect-timeout"          comment:"TCP connection timeout"`
-		DataTableLegacy         string            `toml:"data-table,commented"`
-		RollupConfLegacy        string            `toml:"rollup-conf,commented"`
-		MaxDataPoints           int               `toml:"max-data-points"          comment:"max points per metric when internal-aggregation=true"`
-		InternalAggregation     bool              `toml:"internal-aggregation"     comment:"ClickHouse-side aggregation, see doc/aggregation.md"`
-	}
-
-	type Tags struct {
-		Rules      string `toml:"rules"`
-		Date       string `toml:"date"`
-		ExtraWhere string `toml:"extra-where"`
-		InputFile  string `toml:"input-file"`
-		OutputFile string `toml:"output-file"`
-	}
-
-	type Config struct {
-		Common     Common     `toml:"common"`
-		ClickHouse ClickHouse `toml:"clickhouse"`
-		Tags       Tags       `toml:"tags,commented"`
-	}
-
-	cfg := &Config{
-		Common: Common{
-			Listen:               ":9090",
-			PprofListen:          "",
-			MaxMetricsPerTarget:  15000, // This is arbitrary value to protect CH from overload
-			MemoryReturnInterval: 0,
-		},
-		ClickHouse: ClickHouse{
-			URL:                 "http://localhost:8123?cancel_http_readonly_queries_on_client_close=1",
-			ExtraPrefix:         "",
-			ConnectTimeout:      time.Second,
-			DataTableLegacy:     "",
-			RollupConfLegacy:    "auto",
-			MaxDataPoints:       1048576,
-			InternalAggregation: true,
-		},
-		Tags: Tags{},
-	}
-
-	out, err := toml.Marshal(cfg)
-	if err != nil {
-		panic(err)
-	}
-	err = toml.Unmarshal(out, &cfg)
-	if err != nil {
-		panic(err)
-	}
-
-	fmt.Println(string(out))
-
-	// Output:
-	// [common]
-	// # general listener
-	// listen = ':9090'
-	// # listener to serve /debug/pprof requests. '-pprof' argument overrides it
-	// pprof-listen = ''
-	// # limit numbers of queried metrics per target in /render requests, 0 or negative = unlimited
-	// max-metrics-per-target = 15000
-	// # daemon will return the freed memory to the OS when it>0
-	// memory-return-interval = 0
-	//
-	// [clickhouse]
-	// # default url, see https://clickhouse.tech/docs/en/interfaces/http. Can be overwritten with query-params
-	// url = 'http://localhost:8123?cancel_http_readonly_queries_on_client_close=1'
-	// # Max queries to render queiries
-	// render-max-queries = 0
-	// # Concurrent queries to render queiries
-	// render-concurrent-queries = 0
-	// # tree-table = ''
-	// # reverse-tree-table = ''
-	// # date-tree-table = ''
-	// # date-tree-table-version = 0
-	// # tree-timeout = 0
-	// # tag-table = ''
-	// # add extra prefix (directory in graphite) for all metrics, w/o trailing dot
-	// extra-prefix = ''
-	// # TCP connection timeout
-	// connect-timeout = 1000000000
-	// # data-table = ''
-	// # rollup-conf = 'auto'
-	// # max points per metric when internal-aggregation=true
-	// max-data-points = 1048576
-	// # ClickHouse-side aggregation, see doc/aggregation.md
-	// internal-aggregation = true
-	//
-	// # [tags]
-	// # rules = ''
-	// # date = ''
-	// # extra-where = ''
-	// # input-file = ''
-	// # output-file = ''
-}
-
-func TestReadmeComments(t *testing.T) {
-	type TLS struct {
-		Cipher  string `toml:"cipher"`
-		Version string `toml:"version"`
-	}
-	type Config struct {
-		Host string `toml:"host" comment:"Host IP to connect to."`
-		Port int    `toml:"port" comment:"Port of the remote server."`
-		Tls  TLS    `toml:"TLS,commented" comment:"Encryption parameters (optional)"`
-	}
-	example := Config{
-		Host: "127.0.0.1",
-		Port: 4242,
-		Tls: TLS{
-			Cipher:  "AEAD-AES128-GCM-SHA256",
-			Version: "TLS 1.3",
-		},
-	}
-	out, err := toml.Marshal(example)
-	require.NoError(t, err)
-
-	expected := `# Host IP to connect to.
-host = '127.0.0.1'
-# Port of the remote server.
-port = 4242
-
-# Encryption parameters (optional)
-# [TLS]
-# cipher = 'AEAD-AES128-GCM-SHA256'
-# version = 'TLS 1.3'
-`
-	require.Equal(t, expected, string(out))
-}
@@ -1,45 +0,0 @@
-//go:build go1.18 || go1.19 || go1.20 || go1.21
-// +build go1.18 go1.19 go1.20 go1.21
-
-package ossfuzz
-
-import (
-	"fmt"
-	"reflect"
-	"strings"
-
-	"github.com/pelletier/go-toml/v2"
-)
-
-func FuzzToml(data []byte) int {
-	if len(data) >= 2048 {
-		return 0
-	}
-
-	if strings.Contains(string(data), "nan") {
-		return 0
-	}
-
-	var v interface{}
-	err := toml.Unmarshal(data, &v)
-	if err != nil {
-		return 0
-	}
-
-	encoded, err := toml.Marshal(v)
-	if err != nil {
-		panic(fmt.Sprintf("failed to marshal unmarshaled document: %s", err))
-	}
-
-	var v2 interface{}
-	err = toml.Unmarshal(encoded, &v2)
-	if err != nil {
-		panic(fmt.Sprintf("failed round trip: %s", err))
-	}
-
-	if !reflect.DeepEqual(v, v2) {
-		panic(fmt.Sprintf("not equal: %#+v %#+v", v, v2))
-	}
-
-	return 1
-}
@@ -0,0 +1,450 @@
+package toml
+
+import (
+	"strconv"
+	"strings"
+	"testing"
+
+	"github.com/pelletier/go-toml/v2/internal/ast"
+	"github.com/stretchr/testify/require"
+)
+
+//nolint:funlen
+func TestParser_AST_Numbers(t *testing.T) {
+	examples := []struct {
+		desc  string
+		input string
+		kind  ast.Kind
+		err   bool
+	}{
+		{
+			desc:  "integer just digits",
+			input: `1234`,
+			kind:  ast.Integer,
+		},
+		{
+			desc:  "integer zero",
+			input: `0`,
+			kind:  ast.Integer,
+		},
+		{
+			desc:  "integer sign",
+			input: `+99`,
+			kind:  ast.Integer,
+		},
+		{
+			desc:  "integer hex uppercase",
+			input: `0xDEADBEEF`,
+			kind:  ast.Integer,
+		},
+		{
+			desc:  "integer hex lowercase",
+			input: `0xdead_beef`,
+			kind:  ast.Integer,
+		},
+		{
+			desc:  "integer octal",
+			input: `0o01234567`,
+			kind:  ast.Integer,
+		},
+		{
+			desc:  "integer binary",
+			input: `0b11010110`,
+			kind:  ast.Integer,
+		},
+		{
+			desc:  "float zero",
+			input: `0.0`,
+			kind:  ast.Float,
+		},
+		{
+			desc:  "float positive zero",
+			input: `+0.0`,
+			kind:  ast.Float,
+		},
+		{
+			desc:  "float negative zero",
+			input: `-0.0`,
+			kind:  ast.Float,
+		},
+		{
+			desc:  "float pi",
+			input: `3.1415`,
+			kind:  ast.Float,
+		},
+		{
+			desc:  "float negative",
+			input: `-0.01`,
+			kind:  ast.Float,
+		},
+		{
+			desc:  "float signed exponent",
+			input: `5e+22`,
+			kind:  ast.Float,
+		},
+		{
+			desc:  "float exponent lowercase",
+			input: `1e06`,
+			kind:  ast.Float,
+		},
+		{
+			desc:  "float exponent uppercase",
+			input: `-2E-2`,
+			kind:  ast.Float,
+		},
+		{
+			desc:  "float fractional with exponent",
+			input: `6.626e-34`,
+			kind:  ast.Float,
+		},
+		{
+			desc:  "float underscores",
+			input: `224_617.445_991_228`,
+			kind:  ast.Float,
+		},
+		{
+			desc:  "inf",
+			input: `inf`,
+			kind:  ast.Float,
+		},
+		{
+			desc:  "inf negative",
+			input: `-inf`,
+			kind:  ast.Float,
+		},
+		{
+			desc:  "inf positive",
+			input: `+inf`,
+			kind:  ast.Float,
+		},
+		{
+			desc:  "nan",
+			input: `nan`,
+			kind:  ast.Float,
+		},
+		{
+			desc:  "nan negative",
+			input: `-nan`,
+			kind:  ast.Float,
+		},
+		{
+			desc:  "nan positive",
+			input: `+nan`,
+			kind:  ast.Float,
+		},
+	}
+
+	for _, e := range examples {
+		e := e
+		t.Run(e.desc, func(t *testing.T) {
+			p := parser{}
+			p.Reset([]byte(`A = ` + e.input))
+			p.NextExpression()
+			err := p.Error()
+			if e.err {
+				require.Error(t, err)
+			} else {
+				require.NoError(t, err)
+
+				expected := astNode{
+					Kind: ast.KeyValue,
+					Children: []astNode{
+						{Kind: e.kind, Data: []byte(e.input)},
+						{Kind: ast.Key, Data: []byte(`A`)},
+					},
+				}
+				compareNode(t, expected, p.Expression())
+			}
+		})
+	}
+}
+
+type (
+	astNode struct {
+		Kind     ast.Kind
+		Data     []byte
+		Children []astNode
+	}
+)
+
+func compareNode(t *testing.T, e astNode, n *ast.Node) {
+	t.Helper()
+	require.Equal(t, e.Kind, n.Kind)
+	require.Equal(t, e.Data, n.Data)
+
+	compareIterator(t, e.Children, n.Children())
+}
+
+func compareIterator(t *testing.T, expected []astNode, actual ast.Iterator) {
+	t.Helper()
+	idx := 0
+
+	for actual.Next() {
+		n := actual.Node()
+
+		if idx >= len(expected) {
+			t.Fatal("extra child in actual tree")
+		}
+		e := expected[idx]
+
+		compareNode(t, e, n)
+
+		idx++
+	}
+
+	if idx < len(expected) {
+		t.Fatal("missing children in actual", "idx =", idx, "expected =", len(expected))
+	}
+}
+
+//nolint:funlen
+func TestParser_AST(t *testing.T) {
+	examples := []struct {
+		desc  string
+		input string
+		ast   astNode
+		err   bool
+	}{
+		{
+			desc:  "simple string assignment",
+			input: `A = "hello"`,
+			ast: astNode{
+				Kind: ast.KeyValue,
+				Children: []astNode{
+					{
+						Kind: ast.String,
+						Data: []byte(`hello`),
+					},
+					{
+						Kind: ast.Key,
+						Data: []byte(`A`),
+					},
+				},
+			},
+		},
+		{
+			desc:  "simple bool assignment",
+			input: `A = true`,
+			ast: astNode{
+				Kind: ast.KeyValue,
+				Children: []astNode{
+					{
+						Kind: ast.Bool,
+						Data: []byte(`true`),
+					},
+					{
+						Kind: ast.Key,
+						Data: []byte(`A`),
+					},
+				},
+			},
+		},
+		{
+			desc:  "array of strings",
+			input: `A = ["hello", ["world", "again"]]`,
+			ast: astNode{
+				Kind: ast.KeyValue,
+				Children: []astNode{
+					{
+						Kind: ast.Array,
+						Children: []astNode{
+							{
+								Kind: ast.String,
+								Data: []byte(`hello`),
+							},
+							{
+								Kind: ast.Array,
+								Children: []astNode{
+									{
+										Kind: ast.String,
+										Data: []byte(`world`),
+									},
+									{
+										Kind: ast.String,
+										Data: []byte(`again`),
+									},
+								},
+							},
+						},
+					},
+					{
+						Kind: ast.Key,
+						Data: []byte(`A`),
+					},
+				},
+			},
+		},
+		{
+			desc:  "array of arrays of strings",
+			input: `A = ["hello", "world"]`,
+			ast: astNode{
+				Kind: ast.KeyValue,
+				Children: []astNode{
+					{
+						Kind: ast.Array,
+						Children: []astNode{
+							{
+								Kind: ast.String,
+								Data: []byte(`hello`),
+							},
+							{
+								Kind: ast.String,
+								Data: []byte(`world`),
+							},
+						},
+					},
+					{
+						Kind: ast.Key,
+						Data: []byte(`A`),
+					},
+				},
+			},
+		},
+		{
+			desc:  "inline table",
+			input: `name = { first = "Tom", last = "Preston-Werner" }`,
+			ast: astNode{
+				Kind: ast.KeyValue,
+				Children: []astNode{
+					{
+						Kind: ast.InlineTable,
+						Children: []astNode{
+							{
+								Kind: ast.KeyValue,
+								Children: []astNode{
+									{Kind: ast.String, Data: []byte(`Tom`)},
+									{Kind: ast.Key, Data: []byte(`first`)},
+								},
+							},
+							{
+								Kind: ast.KeyValue,
+								Children: []astNode{
+									{Kind: ast.String, Data: []byte(`Preston-Werner`)},
+									{Kind: ast.Key, Data: []byte(`last`)},
+								},
+							},
+						},
+					},
+					{
+						Kind: ast.Key,
+						Data: []byte(`name`),
+					},
+				},
+			},
+		},
+	}
+
+	for _, e := range examples {
+		e := e
+		t.Run(e.desc, func(t *testing.T) {
+			p := parser{}
+			p.Reset([]byte(e.input))
+			p.NextExpression()
+			err := p.Error()
+			if e.err {
+				require.Error(t, err)
+			} else {
+				require.NoError(t, err)
+				compareNode(t, e.ast, p.Expression())
+			}
+		})
+	}
+}
+
+func BenchmarkParseBasicStringWithUnicode(b *testing.B) {
+	p := &parser{}
+	b.Run("4", func(b *testing.B) {
+		input := []byte(`"\u1234\u5678\u9ABC\u1234\u5678\u9ABC"`)
+		b.ReportAllocs()
+		b.SetBytes(int64(len(input)))
+
+		for i := 0; i < b.N; i++ {
+			p.parseBasicString(input)
+		}
+	})
+	b.Run("8", func(b *testing.B) {
+		input := []byte(`"\u12345678\u9ABCDEF0\u12345678\u9ABCDEF0"`)
+		b.ReportAllocs()
+		b.SetBytes(int64(len(input)))
+
+		for i := 0; i < b.N; i++ {
+			p.parseBasicString(input)
+		}
+	})
+}
+
+func BenchmarkParseBasicStringsEasy(b *testing.B) {
+	p := &parser{}
+
+	for _, size := range []int{1, 4, 8, 16, 21} {
+		b.Run(strconv.Itoa(size), func(b *testing.B) {
+			input := []byte(`"` + strings.Repeat("A", size) + `"`)
+
+			b.ReportAllocs()
+			b.SetBytes(int64(len(input)))
+
+			for i := 0; i < b.N; i++ {
+				p.parseBasicString(input)
+			}
+		})
+	}
+}
+
+func TestParser_AST_DateTimes(t *testing.T) {
+	examples := []struct {
+		desc  string
+		input string
+		kind  ast.Kind
+		err   bool
+	}{
+		{
+			desc:  "offset-date-time with delim 'T' and UTC offset",
+			input: `2021-07-21T12:08:05Z`,
+			kind:  ast.DateTime,
+		},
+		{
+			desc:  "offset-date-time with space delim and +8hours offset",
+			input: `2021-07-21 12:08:05+08:00`,
+			kind:  ast.DateTime,
+		},
+		{
+			desc:  "local-date-time with nano second",
+			input: `2021-07-21T12:08:05.666666666`,
+			kind:  ast.LocalDateTime,
+		},
+		{
+			desc:  "local-date-time",
+			input: `2021-07-21T12:08:05`,
+			kind:  ast.LocalDateTime,
+		},
+		{
+			desc:  "local-date",
+			input: `2021-07-21`,
+			kind:  ast.LocalDate,
+		},
+	}
+
+	for _, e := range examples {
+		e := e
+		t.Run(e.desc, func(t *testing.T) {
+			p := parser{}
+			p.Reset([]byte(`A = ` + e.input))
+			p.NextExpression()
+			err := p.Error()
+			if e.err {
+				require.Error(t, err)
+			} else {
+				require.NoError(t, err)
+
+				expected := astNode{
+					Kind: ast.KeyValue,
+					Children: []astNode{
+						{Kind: e.kind, Data: []byte(e.input)},
+						{Kind: ast.Key, Data: []byte(`A`)},
+					},
+				}
+				compareNode(t, expected, p.Expression())
+			}
+		})
+	}
+}
@@ -1,6 +1,4 @@
-package unstable
-
-import "github.com/pelletier/go-toml/v2/internal/characters"
+package toml

 func scanFollows(b []byte, pattern string) bool {
 	n := len(pattern)
@@ -56,16 +54,16 @@ func scanLiteralString(b []byte) ([]byte, []byte, error) {
 		case '\'':
 			return b[:i+1], b[i+1:], nil
 		case '\n', '\r':
-			return nil, nil, NewParserError(b[i:i+1], "literal strings cannot have new lines")
+			return nil, b[i+1:], newDecodeError(b[i:i+1], "literal strings cannot have new lines")
 		}
-		size := characters.Utf8ValidNext(b[i:])
+		size := utf8ValidNext(b[i:])
 		if size == 0 {
-			return nil, nil, NewParserError(b[i:i+1], "invalid character")
+			return nil, b[i+1:], newDecodeError(b[i:i+1], "invalid character")
 		}
 		i += size
 	}

-	return nil, nil, NewParserError(b[len(b):], "unterminated literal string")
+	return nil, b[len(b):], newDecodeError(b[len(b):], "unterminated literal string")
 }

 func scanMultilineLiteralString(b []byte) ([]byte, []byte, error) {
@@ -100,39 +98,39 @@ func scanMultilineLiteralString(b []byte) ([]byte, []byte, error) {
 				i++

 				if i < len(b) && b[i] == '\'' {
-					return nil, nil, NewParserError(b[i-3:i+1], "''' not allowed in multiline literal string")
+					return nil, b[i:], newDecodeError(b[i-3:i+1], "''' not allowed in multiline literal string")
 				}

 				return b[:i], b[i:], nil
 			}
 		case '\r':
 			if len(b) < i+2 {
-				return nil, nil, NewParserError(b[len(b):], `need a \n after \r`)
+				return nil, b[i:], newDecodeError(b[len(b):], `need a \n after \r`)
 			}
 			if b[i+1] != '\n' {
-				return nil, nil, NewParserError(b[i:i+2], `need a \n after \r`)
+				return nil, b[i+2:], newDecodeError(b[i:i+2], `need a \n after \r`)
 			}
 			i += 2 // skip the \n
 			continue
 		}
-		size := characters.Utf8ValidNext(b[i:])
+		size := utf8ValidNext(b[i:])
 		if size == 0 {
-			return nil, nil, NewParserError(b[i:i+1], "invalid character")
+			return nil, b[i:], newDecodeError(b[i:i+1], "invalid character")
 		}
 		i += size
 	}

-	return nil, nil, NewParserError(b[len(b):], `multiline literal string not terminated by '''`)
+	return nil, b[len(b):], newDecodeError(b[len(b):], `multiline literal string not terminated by '''`)
 }

 func scanWindowsNewline(b []byte) ([]byte, []byte, error) {
 	const lenCRLF = 2
 	if len(b) < lenCRLF {
-		return nil, nil, NewParserError(b, "windows new line expected")
+		return nil, b, newDecodeError(b, "windows new line expected")
 	}

 	if b[1] != '\n' {
-		return nil, nil, NewParserError(b, `windows new line should be \r\n`)
+		return nil, b[2:], newDecodeError(b, `windows new line should be \r\n`)
 	}

 	return b[:lenCRLF], b[lenCRLF:], nil
@@ -151,6 +149,7 @@ func scanWhitespace(b []byte) ([]byte, []byte) {
 	return b, b[len(b):]
 }

+//nolint:unparam
 func scanComment(b []byte) ([]byte, []byte, error) {
 	// comment-start-symbol = %x23 ; #
 	// non-ascii = %x80-D7FF / %xE000-10FFFF
@@ -166,11 +165,11 @@ func scanComment(b []byte) ([]byte, []byte, error) {
 			if i+1 < len(b) && b[i+1] == '\n' {
 				return b[:i+1], b[i+1:], nil
 			}
-			return nil, nil, NewParserError(b[i:i+1], "invalid character in comment")
+			return nil, nil, newDecodeError(b[i:i+1], "invalid character in comment")
 		}
-		size := characters.Utf8ValidNext(b[i:])
+		size := utf8ValidNext(b[i:])
 		if size == 0 {
-			return nil, nil, NewParserError(b[i:i+1], "invalid character in comment")
+			return nil, b[i+1:], newDecodeError(b[i:i+1], "invalid character in comment")
 		}

 		i += size
@@ -193,17 +192,17 @@ func scanBasicString(b []byte) ([]byte, bool, []byte, error) {
 		case '"':
 			return b[:i+1], escaped, b[i+1:], nil
 		case '\n', '\r':
-			return nil, escaped, nil, NewParserError(b[i:i+1], "basic strings cannot have new lines")
+			return nil, escaped, b[i+1:], newDecodeError(b[i:i+1], "basic strings cannot have new lines")
 		case '\\':
 			if len(b) < i+2 {
-				return nil, escaped, nil, NewParserError(b[i:i+1], "need a character after \\")
+				return nil, escaped, b[i+1:], newDecodeError(b[i:i+1], "need a character after \\")
 			}
 			escaped = true
 			i++ // skip the next character
 		}
 	}

-	return nil, escaped, nil, NewParserError(b[len(b):], `basic string not terminated by "`)
+	return nil, escaped, b[len(b):], newDecodeError(b[len(b):], `basic string not terminated by "`)
 }

 func scanMultilineBasicString(b []byte) ([]byte, bool, []byte, error) {
@@ -244,27 +243,27 @@ func scanMultilineBasicString(b []byte) ([]byte, bool, []byte, error) {
 				i++

 				if i < len(b) && b[i] == '"' {
-					return nil, escaped, nil, NewParserError(b[i-3:i+1], `""" not allowed in multiline basic string`)
+					return nil, escaped, b[i+1:], newDecodeError(b[i-3:i+1], `""" not allowed in multiline basic string`)
 				}

 				return b[:i], escaped, b[i:], nil
 			}
 		case '\\':
 			if len(b) < i+2 {
-				return nil, escaped, nil, NewParserError(b[len(b):], "need a character after \\")
+				return nil, escaped, b[len(b):], newDecodeError(b[len(b):], "need a character after \\")
 			}
 			escaped = true
 			i++ // skip the next character
 		case '\r':
 			if len(b) < i+2 {
-				return nil, escaped, nil, NewParserError(b[len(b):], `need a \n after \r`)
+				return nil, escaped, b[len(b):], newDecodeError(b[len(b):], `need a \n after \r`)
 			}
 			if b[i+1] != '\n' {
-				return nil, escaped, nil, NewParserError(b[i:i+2], `need a \n after \r`)
+				return nil, escaped, b[i+2:], newDecodeError(b[i:i+2], `need a \n after \r`)
 			}
 			i++ // skip the \n
 		}
 	}

-	return nil, escaped, nil, NewParserError(b[len(b):], `multiline basic string not terminated by """`)
+	return nil, escaped, b[len(b):], newDecodeError(b[len(b):], `multiline basic string not terminated by """`)
 }
@@ -1,9 +1,9 @@
 package toml

 import (
+	"github.com/pelletier/go-toml/v2/internal/ast"
 	"github.com/pelletier/go-toml/v2/internal/danger"
 	"github.com/pelletier/go-toml/v2/internal/tracker"
-	"github.com/pelletier/go-toml/v2/unstable"
 )

 type strict struct {
@@ -12,10 +12,10 @@ type strict struct {
 	// Tracks the current key being processed.
 	key tracker.KeyTracker

-	missing []unstable.ParserError
+	missing []decodeError
 }

-func (s *strict) EnterTable(node *unstable.Node) {
+func (s *strict) EnterTable(node *ast.Node) {
 	if !s.Enabled {
 		return
 	}
@@ -23,7 +23,7 @@ func (s *strict) EnterTable(node *unstable.Node) {
 	s.key.UpdateTable(node)
 }

-func (s *strict) EnterArrayTable(node *unstable.Node) {
+func (s *strict) EnterArrayTable(node *ast.Node) {
 	if !s.Enabled {
 		return
 	}
@@ -31,7 +31,7 @@ func (s *strict) EnterArrayTable(node *unstable.Node) {
 	s.key.UpdateArrayTable(node)
 }

-func (s *strict) EnterKeyValue(node *unstable.Node) {
+func (s *strict) EnterKeyValue(node *ast.Node) {
 	if !s.Enabled {
 		return
 	}
@@ -39,7 +39,7 @@ func (s *strict) EnterKeyValue(node *unstable.Node) {
 	s.key.Push(node)
 }

-func (s *strict) ExitKeyValue(node *unstable.Node) {
+func (s *strict) ExitKeyValue(node *ast.Node) {
 	if !s.Enabled {
 		return
 	}
@@ -47,27 +47,27 @@ func (s *strict) ExitKeyValue(node *unstable.Node) {
 	s.key.Pop(node)
 }

-func (s *strict) MissingTable(node *unstable.Node) {
+func (s *strict) MissingTable(node *ast.Node) {
 	if !s.Enabled {
 		return
 	}

-	s.missing = append(s.missing, unstable.ParserError{
-		Highlight: keyLocation(node),
-		Message:   "missing table",
-		Key:       s.key.Key(),
+	s.missing = append(s.missing, decodeError{
+		highlight: keyLocation(node),
+		message:   "missing table",
+		key:       s.key.Key(),
 	})
 }

-func (s *strict) MissingField(node *unstable.Node) {
+func (s *strict) MissingField(node *ast.Node) {
 	if !s.Enabled {
 		return
 	}

-	s.missing = append(s.missing, unstable.ParserError{
-		Highlight: keyLocation(node),
-		Message:   "missing field",
-		Key:       s.key.Key(),
+	s.missing = append(s.missing, decodeError{
+		highlight: keyLocation(node),
+		message:   "missing field",
+		key:       s.key.Key(),
 	})
 }

@@ -88,7 +88,7 @@ func (s *strict) Error(doc []byte) error {
 	return err
 }

-func keyLocation(node *unstable.Node) []byte {
+func keyLocation(node *ast.Node) []byte {
 	k := node.Key()

 	hasOne := k.Next()
@@ -1,4 +1,3 @@
-//go:generate go run github.com/toml-lang/toml-test/cmd/toml-test@master -copy ./tests
 //go:generate go run ./cmd/tomltestgen/main.go -o toml_testgen_test.go

 // This is a support file for toml_testgen_test.go
@@ -6,9 +6,9 @@ import (
 	"time"
 )

-var timeType = reflect.TypeOf((*time.Time)(nil)).Elem()
-var textMarshalerType = reflect.TypeOf((*encoding.TextMarshaler)(nil)).Elem()
-var textUnmarshalerType = reflect.TypeOf((*encoding.TextUnmarshaler)(nil)).Elem()
-var mapStringInterfaceType = reflect.TypeOf(map[string]interface{}(nil))
-var sliceInterfaceType = reflect.TypeOf([]interface{}(nil))
+var timeType = reflect.TypeOf(time.Time{})
+var textMarshalerType = reflect.TypeOf(new(encoding.TextMarshaler)).Elem()
+var textUnmarshalerType = reflect.TypeOf(new(encoding.TextUnmarshaler)).Elem()
+var mapStringInterfaceType = reflect.TypeOf(map[string]interface{}{})
+var sliceInterfaceType = reflect.TypeOf([]interface{}{})
 var stringType = reflect.TypeOf("")
@@ -12,16 +12,16 @@ import (
 	"sync/atomic"
 	"time"

+	"github.com/pelletier/go-toml/v2/internal/ast"
 	"github.com/pelletier/go-toml/v2/internal/danger"
 	"github.com/pelletier/go-toml/v2/internal/tracker"
-	"github.com/pelletier/go-toml/v2/unstable"
 )

 // Unmarshal deserializes a TOML document into a Go value.
 //
 // It is a shortcut for Decoder.Decode() with the default options.
 func Unmarshal(data []byte, v interface{}) error {
-	p := unstable.Parser{}
+	p := parser{}
 	p.Reset(data)
 	d := decoder{p: &p}

@@ -60,7 +60,7 @@ func (d *Decoder) DisallowUnknownFields() *Decoder {
 // are ignored. See Decoder.DisallowUnknownFields() to change this behavior.
 //
 // When a TOML local date, time, or date-time is decoded into a time.Time, its
-// value is represented in time.Local timezone. Otherwise the appropriate Local*
+// value is represented in time.Local timezone. Otherwise the approriate Local*
 // structure is used. For time values, precision up to the nanosecond is
 // supported by truncating extra digits.
 //
@@ -101,7 +101,7 @@ func (d *Decoder) Decode(v interface{}) error {
 		return fmt.Errorf("toml: %w", err)
 	}

-	p := unstable.Parser{}
+	p := parser{}
 	p.Reset(b)
 	dec := decoder{
 		p: &p,
@@ -115,7 +115,7 @@ func (d *Decoder) Decode(v interface{}) error {

 type decoder struct {
 	// Which parser instance in use for this decoding session.
-	p *unstable.Parser
+	p *parser

 	// Flag indicating that the current expression is stashed.
 	// If set to true, calling nextExpr will not actually pull a new expression
@@ -149,19 +149,15 @@ type errorContext struct {
 }

 func (d *decoder) typeMismatchError(toml string, target reflect.Type) error {
-	return fmt.Errorf("toml: %s", d.typeMismatchString(toml, target))
-}
-
-func (d *decoder) typeMismatchString(toml string, target reflect.Type) string {
 	if d.errorContext != nil && d.errorContext.Struct != nil {
 		ctx := d.errorContext
 		f := ctx.Struct.FieldByIndex(ctx.Field)
-		return fmt.Sprintf("cannot decode TOML %s into struct field %s.%s of type %s", toml, ctx.Struct, f.Name, f.Type)
+		return fmt.Errorf("toml: cannot decode TOML %s into struct field %s.%s of type %s", toml, ctx.Struct, f.Name, f.Type)
 	}
-	return fmt.Sprintf("cannot decode TOML %s into a Go value of type %s", toml, target)
+	return fmt.Errorf("toml: cannot decode TOML %s into a Go value of type %s", toml, target)
 }

-func (d *decoder) expr() *unstable.Node {
+func (d *decoder) expr() *ast.Node {
 	return d.p.Expression()
 }

@@ -212,12 +208,12 @@ func (d *decoder) FromParser(v interface{}) error {

 	err := d.fromParser(r)
 	if err == nil {
-		return d.strict.Error(d.p.Data())
+		return d.strict.Error(d.p.data)
 	}

-	var e *unstable.ParserError
+	var e *decodeError
 	if errors.As(err, &e) {
-		return wrapDecodeError(d.p.Data(), e)
+		return wrapDecodeError(d.p.data, e)
 	}

 	return err
@@ -238,16 +234,16 @@ func (d *decoder) fromParser(root reflect.Value) error {
 Rules for the unmarshal code:

 - The stack is used to keep track of which values need to be set where.
- handle* functions <=> switch on a given unstable.Kind.
+- handle* functions <=> switch on a given ast.Kind.
 - unmarshalX* functions need to unmarshal a node of kind X.
 - An "object" is either a struct or a map.
 */

-func (d *decoder) handleRootExpression(expr *unstable.Node, v reflect.Value) error {
+func (d *decoder) handleRootExpression(expr *ast.Node, v reflect.Value) error {
 	var x reflect.Value
 	var err error

-	if !(d.skipUntilTable && expr.Kind == unstable.KeyValue) {
+	if !(d.skipUntilTable && expr.Kind == ast.KeyValue) {
 		err = d.seen.CheckExpression(expr)
 		if err != nil {
 			return err
@@ -255,16 +251,16 @@ func (d *decoder) handleRootExpression(expr *unstable.Node, v reflect.Value) err
 	}

 	switch expr.Kind {
-	case unstable.KeyValue:
+	case ast.KeyValue:
 		if d.skipUntilTable {
 			return nil
 		}
 		x, err = d.handleKeyValue(expr, v)
-	case unstable.Table:
+	case ast.Table:
 		d.skipUntilTable = false
 		d.strict.EnterTable(expr)
 		x, err = d.handleTable(expr.Key(), v)
-	case unstable.ArrayTable:
+	case ast.ArrayTable:
 		d.skipUntilTable = false
 		d.strict.EnterArrayTable(expr)
 		x, err = d.handleArrayTable(expr.Key(), v)
@@ -273,7 +269,7 @@ func (d *decoder) handleRootExpression(expr *unstable.Node, v reflect.Value) err
 	}

 	if d.skipUntilTable {
-		if expr.Kind == unstable.Table || expr.Kind == unstable.ArrayTable {
+		if expr.Kind == ast.Table || expr.Kind == ast.ArrayTable {
 			d.strict.MissingTable(expr)
 		}
 	} else if err == nil && x.IsValid() {
@@ -283,14 +279,14 @@ func (d *decoder) handleRootExpression(expr *unstable.Node, v reflect.Value) err
 	return err
 }

-func (d *decoder) handleArrayTable(key unstable.Iterator, v reflect.Value) (reflect.Value, error) {
+func (d *decoder) handleArrayTable(key ast.Iterator, v reflect.Value) (reflect.Value, error) {
 	if key.Next() {
 		return d.handleArrayTablePart(key, v)
 	}
 	return d.handleKeyValues(v)
 }

-func (d *decoder) handleArrayTableCollectionLast(key unstable.Iterator, v reflect.Value) (reflect.Value, error) {
+func (d *decoder) handleArrayTableCollectionLast(key ast.Iterator, v reflect.Value) (reflect.Value, error) {
 	switch v.Kind() {
 	case reflect.Interface:
 		elem := v.Elem()
@@ -343,13 +339,13 @@ func (d *decoder) handleArrayTableCollectionLast(key unstable.Iterator, v reflec
 	case reflect.Array:
 		idx := d.arrayIndex(true, v)
 		if idx >= v.Len() {
-			return v, fmt.Errorf("%s at position %d", d.typeMismatchError("array table", v.Type()), idx)
+			return v, fmt.Errorf("toml: cannot decode array table into %s at position %d", v.Type(), idx)
 		}
 		elem := v.Index(idx)
 		_, err := d.handleArrayTable(key, elem)
 		return v, err
 	default:
-		return reflect.Value{}, d.typeMismatchError("array table", v.Type())
+		return reflect.Value{}, fmt.Errorf("toml: cannot decode array table into a %s", v.Type())
 	}
 }

@@ -357,7 +353,7 @@ func (d *decoder) handleArrayTableCollectionLast(key unstable.Iterator, v reflec
 // evaluated like a normal key, but if it returns a collection, it also needs to
 // point to the last element of the collection. Unless it is the last part of
 // the key, then it needs to create a new element at the end.
-func (d *decoder) handleArrayTableCollection(key unstable.Iterator, v reflect.Value) (reflect.Value, error) {
+func (d *decoder) handleArrayTableCollection(key ast.Iterator, v reflect.Value) (reflect.Value, error) {
 	if key.IsLast() {
 		return d.handleArrayTableCollectionLast(key, v)
 	}
@@ -394,7 +390,7 @@ func (d *decoder) handleArrayTableCollection(key unstable.Iterator, v reflect.Va
 	case reflect.Array:
 		idx := d.arrayIndex(false, v)
 		if idx >= v.Len() {
-			return v, fmt.Errorf("%s at position %d", d.typeMismatchError("array table", v.Type()), idx)
+			return v, fmt.Errorf("toml: cannot decode array table into %s at position %d", v.Type(), idx)
 		}
 		elem := v.Index(idx)
 		_, err := d.handleArrayTable(key, elem)
@@ -404,7 +400,7 @@ func (d *decoder) handleArrayTableCollection(key unstable.Iterator, v reflect.Va
 	return d.handleArrayTable(key, v)
 }

-func (d *decoder) handleKeyPart(key unstable.Iterator, v reflect.Value, nextFn handlerFn, makeFn valueMakerFn) (reflect.Value, error) {
+func (d *decoder) handleKeyPart(key ast.Iterator, v reflect.Value, nextFn handlerFn, makeFn valueMakerFn) (reflect.Value, error) {
 	var rv reflect.Value

 	// First, dispatch over v to make sure it is a valid object.
@@ -421,10 +417,7 @@ func (d *decoder) handleKeyPart(key unstable.Iterator, v reflect.Value, nextFn h
 		vt := v.Type()

 		// Create the key for the map element. Convert to key type.
-		mk, err := d.keyFromData(vt.Key(), key.Node().Data)
-		if err != nil {
-			return reflect.Value{}, err
-		}
+		mk := reflect.ValueOf(string(key.Node().Data)).Convert(vt.Key())

 		// If the map does not exist, create it.
 		if v.IsNil() {
@@ -525,7 +518,7 @@ func (d *decoder) handleKeyPart(key unstable.Iterator, v reflect.Value, nextFn h
 // HandleArrayTablePart navigates the Go structure v using the key v. It is
 // only used for the prefix (non-last) parts of an array-table. When
 // encountering a collection, it should go to the last element.
-func (d *decoder) handleArrayTablePart(key unstable.Iterator, v reflect.Value) (reflect.Value, error) {
+func (d *decoder) handleArrayTablePart(key ast.Iterator, v reflect.Value) (reflect.Value, error) {
 	var makeFn valueMakerFn
 	if key.IsLast() {
 		makeFn = makeSliceInterface
@@ -537,10 +530,10 @@ func (d *decoder) handleArrayTablePart(key unstable.Iterator, v reflect.Value) (

 // HandleTable returns a reference when it has checked the next expression but
 // cannot handle it.
-func (d *decoder) handleTable(key unstable.Iterator, v reflect.Value) (reflect.Value, error) {
+func (d *decoder) handleTable(key ast.Iterator, v reflect.Value) (reflect.Value, error) {
 	if v.Kind() == reflect.Slice {
 		if v.Len() == 0 {
-			return reflect.Value{}, unstable.NewParserError(key.Node().Data, "cannot store a table in a slice")
+			return reflect.Value{}, newDecodeError(key.Node().Data, "cannot store a table in a slice")
 		}
 		elem := v.Index(v.Len() - 1)
 		x, err := d.handleTable(key, elem)
@@ -567,7 +560,7 @@ func (d *decoder) handleKeyValues(v reflect.Value) (reflect.Value, error) {
 	var rv reflect.Value
 	for d.nextExpr() {
 		expr := d.expr()
-		if expr.Kind != unstable.KeyValue {
+		if expr.Kind != ast.KeyValue {
 			// Stash the expression so that fromParser can just loop and use
 			// the right handler.
 			// We could just recurse ourselves here, but at least this gives a
@@ -594,7 +587,7 @@ func (d *decoder) handleKeyValues(v reflect.Value) (reflect.Value, error) {
 }

 type (
-	handlerFn    func(key unstable.Iterator, v reflect.Value) (reflect.Value, error)
+	handlerFn    func(key ast.Iterator, v reflect.Value) (reflect.Value, error)
 	valueMakerFn func() reflect.Value
 )

@@ -606,11 +599,11 @@ func makeSliceInterface() reflect.Value {
 	return reflect.MakeSlice(sliceInterfaceType, 0, 16)
 }

-func (d *decoder) handleTablePart(key unstable.Iterator, v reflect.Value) (reflect.Value, error) {
+func (d *decoder) handleTablePart(key ast.Iterator, v reflect.Value) (reflect.Value, error) {
 	return d.handleKeyPart(key, v, d.handleTable, makeMapStringInterface)
 }

-func (d *decoder) tryTextUnmarshaler(node *unstable.Node, v reflect.Value) (bool, error) {
+func (d *decoder) tryTextUnmarshaler(node *ast.Node, v reflect.Value) (bool, error) {
 	// Special case for time, because we allow to unmarshal to it from
 	// different kind of AST nodes.
 	if v.Type() == timeType {
@@ -620,7 +613,7 @@ func (d *decoder) tryTextUnmarshaler(node *unstable.Node, v reflect.Value) (bool
 	if v.CanAddr() && v.Addr().Type().Implements(textUnmarshalerType) {
 		err := v.Addr().Interface().(encoding.TextUnmarshaler).UnmarshalText(node.Data)
 		if err != nil {
-			return false, unstable.NewParserError(d.p.Raw(node.Raw), "%w", err)
+			return false, newDecodeError(d.p.Raw(node.Raw), "%w", err)
 		}

 		return true, nil
@@ -629,7 +622,7 @@ func (d *decoder) tryTextUnmarshaler(node *unstable.Node, v reflect.Value) (bool
 	return false, nil
 }

-func (d *decoder) handleValue(value *unstable.Node, v reflect.Value) error {
+func (d *decoder) handleValue(value *ast.Node, v reflect.Value) error {
 	for v.Kind() == reflect.Ptr {
 		v = initAndDereferencePointer(v)
 	}
@@ -640,32 +633,32 @@ func (d *decoder) handleValue(value *unstable.Node, v reflect.Value) error {
 	}

 	switch value.Kind {
-	case unstable.String:
+	case ast.String:
 		return d.unmarshalString(value, v)
-	case unstable.Integer:
+	case ast.Integer:
 		return d.unmarshalInteger(value, v)
-	case unstable.Float:
+	case ast.Float:
 		return d.unmarshalFloat(value, v)
-	case unstable.Bool:
+	case ast.Bool:
 		return d.unmarshalBool(value, v)
-	case unstable.DateTime:
+	case ast.DateTime:
 		return d.unmarshalDateTime(value, v)
-	case unstable.LocalDate:
+	case ast.LocalDate:
 		return d.unmarshalLocalDate(value, v)
-	case unstable.LocalTime:
+	case ast.LocalTime:
 		return d.unmarshalLocalTime(value, v)
-	case unstable.LocalDateTime:
+	case ast.LocalDateTime:
 		return d.unmarshalLocalDateTime(value, v)
-	case unstable.InlineTable:
+	case ast.InlineTable:
 		return d.unmarshalInlineTable(value, v)
-	case unstable.Array:
+	case ast.Array:
 		return d.unmarshalArray(value, v)
 	default:
 		panic(fmt.Errorf("handleValue not implemented for %s", value.Kind))
 	}
 }

-func (d *decoder) unmarshalArray(array *unstable.Node, v reflect.Value) error {
+func (d *decoder) unmarshalArray(array *ast.Node, v reflect.Value) error {
 	switch v.Kind() {
 	case reflect.Slice:
 		if v.IsNil() {
@@ -736,7 +729,7 @@ func (d *decoder) unmarshalArray(array *unstable.Node, v reflect.Value) error {
 	return nil
 }

-func (d *decoder) unmarshalInlineTable(itable *unstable.Node, v reflect.Value) error {
+func (d *decoder) unmarshalInlineTable(itable *ast.Node, v reflect.Value) error {
 	// Make sure v is an initialized object.
 	switch v.Kind() {
 	case reflect.Map:
@@ -753,7 +746,7 @@ func (d *decoder) unmarshalInlineTable(itable *unstable.Node, v reflect.Value) e
 		}
 		return d.unmarshalInlineTable(itable, elem)
 	default:
-		return unstable.NewParserError(d.p.Raw(itable.Raw), "cannot store inline table in Go type %s", v.Kind())
+		return newDecodeError(itable.Data, "cannot store inline table in Go type %s", v.Kind())
 	}

 	it := itable.Children()
@@ -772,7 +765,7 @@ func (d *decoder) unmarshalInlineTable(itable *unstable.Node, v reflect.Value) e
 	return nil
 }

-func (d *decoder) unmarshalDateTime(value *unstable.Node, v reflect.Value) error {
+func (d *decoder) unmarshalDateTime(value *ast.Node, v reflect.Value) error {
 	dt, err := parseDateTime(value.Data)
 	if err != nil {
 		return err
@@ -782,7 +775,7 @@ func (d *decoder) unmarshalDateTime(value *unstable.Node, v reflect.Value) error
 	return nil
 }

-func (d *decoder) unmarshalLocalDate(value *unstable.Node, v reflect.Value) error {
+func (d *decoder) unmarshalLocalDate(value *ast.Node, v reflect.Value) error {
 	ld, err := parseLocalDate(value.Data)
 	if err != nil {
 		return err
@@ -799,28 +792,28 @@ func (d *decoder) unmarshalLocalDate(value *unstable.Node, v reflect.Value) erro
 	return nil
 }

-func (d *decoder) unmarshalLocalTime(value *unstable.Node, v reflect.Value) error {
+func (d *decoder) unmarshalLocalTime(value *ast.Node, v reflect.Value) error {
 	lt, rest, err := parseLocalTime(value.Data)
 	if err != nil {
 		return err
 	}

 	if len(rest) > 0 {
-		return unstable.NewParserError(rest, "extra characters at the end of a local time")
+		return newDecodeError(rest, "extra characters at the end of a local time")
 	}

 	v.Set(reflect.ValueOf(lt))
 	return nil
 }

-func (d *decoder) unmarshalLocalDateTime(value *unstable.Node, v reflect.Value) error {
+func (d *decoder) unmarshalLocalDateTime(value *ast.Node, v reflect.Value) error {
 	ldt, rest, err := parseLocalDateTime(value.Data)
 	if err != nil {
 		return err
 	}

 	if len(rest) > 0 {
-		return unstable.NewParserError(rest, "extra characters at the end of a local date time")
+		return newDecodeError(rest, "extra characters at the end of a local date time")
 	}

 	if v.Type() == timeType {
@@ -835,7 +828,7 @@ func (d *decoder) unmarshalLocalDateTime(value *unstable.Node, v reflect.Value)
 	return nil
 }

-func (d *decoder) unmarshalBool(value *unstable.Node, v reflect.Value) error {
+func (d *decoder) unmarshalBool(value *ast.Node, v reflect.Value) error {
 	b := value.Data[0] == 't'

 	switch v.Kind() {
@@ -844,13 +837,13 @@ func (d *decoder) unmarshalBool(value *unstable.Node, v reflect.Value) error {
 	case reflect.Interface:
 		v.Set(reflect.ValueOf(b))
 	default:
-		return unstable.NewParserError(value.Data, "cannot assign boolean to a %t", b)
+		return newDecodeError(value.Data, "cannot assign boolean to a %t", b)
 	}

 	return nil
 }

-func (d *decoder) unmarshalFloat(value *unstable.Node, v reflect.Value) error {
+func (d *decoder) unmarshalFloat(value *ast.Node, v reflect.Value) error {
 	f, err := parseFloat(value.Data)
 	if err != nil {
 		return err
@@ -861,13 +854,13 @@ func (d *decoder) unmarshalFloat(value *unstable.Node, v reflect.Value) error {
 		v.SetFloat(f)
 	case reflect.Float32:
 		if f > math.MaxFloat32 {
-			return unstable.NewParserError(value.Data, "number %f does not fit in a float32", f)
+			return newDecodeError(value.Data, "number %f does not fit in a float32", f)
 		}
 		v.SetFloat(f)
 	case reflect.Interface:
 		v.Set(reflect.ValueOf(f))
 	default:
-		return unstable.NewParserError(value.Data, "float cannot be assigned to %s", v.Kind())
+		return newDecodeError(value.Data, "float cannot be assigned to %s", v.Kind())
 	}

 	return nil
@@ -893,12 +886,7 @@ func init() {
 	}
 }

-func (d *decoder) unmarshalInteger(value *unstable.Node, v reflect.Value) error {
-	kind := v.Kind()
-	if kind == reflect.Float32 || kind == reflect.Float64 {
-		return d.unmarshalFloat(value, v)
-	}
-
+func (d *decoder) unmarshalInteger(value *ast.Node, v reflect.Value) error {
 	i, err := parseInteger(value.Data)
 	if err != nil {
 		return err
@@ -906,7 +894,7 @@ func (d *decoder) unmarshalInteger(value *unstable.Node, v reflect.Value) error

 	var r reflect.Value

-	switch kind {
+	switch v.Kind() {
 	case reflect.Int64:
 		v.SetInt(i)
 		return nil
@@ -967,7 +955,7 @@ func (d *decoder) unmarshalInteger(value *unstable.Node, v reflect.Value) error
 	case reflect.Interface:
 		r = reflect.ValueOf(i)
 	default:
-		return unstable.NewParserError(d.p.Raw(value.Raw), d.typeMismatchString("integer", v.Type()))
+		return d.typeMismatchError("integer", v.Type())
 	}

 	if !r.Type().AssignableTo(v.Type()) {
@@ -979,20 +967,20 @@ func (d *decoder) unmarshalInteger(value *unstable.Node, v reflect.Value) error
 	return nil
 }

-func (d *decoder) unmarshalString(value *unstable.Node, v reflect.Value) error {
+func (d *decoder) unmarshalString(value *ast.Node, v reflect.Value) error {
 	switch v.Kind() {
 	case reflect.String:
 		v.SetString(string(value.Data))
 	case reflect.Interface:
 		v.Set(reflect.ValueOf(string(value.Data)))
 	default:
-		return unstable.NewParserError(d.p.Raw(value.Raw), d.typeMismatchString("string", v.Type()))
+		return newDecodeError(d.p.Raw(value.Raw), "cannot store TOML string into a Go %s", v.Kind())
 	}

 	return nil
 }

-func (d *decoder) handleKeyValue(expr *unstable.Node, v reflect.Value) (reflect.Value, error) {
+func (d *decoder) handleKeyValue(expr *ast.Node, v reflect.Value) (reflect.Value, error) {
 	d.strict.EnterKeyValue(expr)

 	v, err := d.handleKeyValueInner(expr.Key(), expr.Value(), v)
@@ -1006,7 +994,7 @@ func (d *decoder) handleKeyValue(expr *unstable.Node, v reflect.Value) (reflect.
 	return v, err
 }

-func (d *decoder) handleKeyValueInner(key unstable.Iterator, value *unstable.Node, v reflect.Value) (reflect.Value, error) {
+func (d *decoder) handleKeyValueInner(key ast.Iterator, value *ast.Node, v reflect.Value) (reflect.Value, error) {
 	if key.Next() {
 		// Still scoping the key
 		return d.handleKeyValuePart(key, value, v)
@@ -1016,32 +1004,7 @@ func (d *decoder) handleKeyValueInner(key unstable.Iterator, value *unstable.Nod
 	return reflect.Value{}, d.handleValue(value, v)
 }

-func (d *decoder) keyFromData(keyType reflect.Type, data []byte) (reflect.Value, error) {
-	switch {
-	case stringType.AssignableTo(keyType):
-		return reflect.ValueOf(string(data)), nil
-
-	case stringType.ConvertibleTo(keyType):
-		return reflect.ValueOf(string(data)).Convert(keyType), nil
-
-	case keyType.Implements(textUnmarshalerType):
-		mk := reflect.New(keyType.Elem())
-		if err := mk.Interface().(encoding.TextUnmarshaler).UnmarshalText(data); err != nil {
-			return reflect.Value{}, fmt.Errorf("toml: error unmarshalling key type %s from text: %w", stringType, err)
-		}
-		return mk, nil
-
-	case reflect.PtrTo(keyType).Implements(textUnmarshalerType):
-		mk := reflect.New(keyType)
-		if err := mk.Interface().(encoding.TextUnmarshaler).UnmarshalText(data); err != nil {
-			return reflect.Value{}, fmt.Errorf("toml: error unmarshalling key type %s from text: %w", stringType, err)
-		}
-		return mk.Elem(), nil
-	}
-	return reflect.Value{}, fmt.Errorf("toml: cannot convert map key of type %s to expected type %s", stringType, keyType)
-}
-
-func (d *decoder) handleKeyValuePart(key unstable.Iterator, value *unstable.Node, v reflect.Value) (reflect.Value, error) {
+func (d *decoder) handleKeyValuePart(key ast.Iterator, value *ast.Node, v reflect.Value) (reflect.Value, error) {
 	// contains the replacement for v
 	var rv reflect.Value

@@ -1051,9 +1014,16 @@ func (d *decoder) handleKeyValuePart(key unstable.Iterator, value *unstable.Node
 	case reflect.Map:
 		vt := v.Type()

-		mk, err := d.keyFromData(vt.Key(), key.Node().Data)
-		if err != nil {
-			return reflect.Value{}, err
+		mk := reflect.ValueOf(string(key.Node().Data))
+		mkt := stringType
+
+		keyType := vt.Key()
+		if !mkt.AssignableTo(keyType) {
+			if !mkt.ConvertibleTo(keyType) {
+				return reflect.Value{}, fmt.Errorf("toml: cannot convert map key of type %s to expected type %s", mkt, keyType)
+			}
+
+			mk = mk.Convert(keyType)
 		}

 		// If the map does not exist, create it.
@@ -1064,9 +1034,15 @@ func (d *decoder) handleKeyValuePart(key unstable.Iterator, value *unstable.Node

 		mv := v.MapIndex(mk)
 		set := false
-		if !mv.IsValid() || key.IsLast() {
+		if !mv.IsValid() {
 			set = true
 			mv = reflect.New(v.Type().Elem()).Elem()
+		} else {
+			if key.IsLast() {
+				var x interface{}
+				mv = reflect.ValueOf(&x).Elem()
+				set = true
+			}
 		}

 		nv, err := d.handleKeyValueInner(key, value, mv)
@@ -1096,19 +1072,6 @@ func (d *decoder) handleKeyValuePart(key unstable.Iterator, value *unstable.Node
 		d.errorContext.Field = path

 		f := fieldByIndex(v, path)
-
-		if !f.CanAddr() {
-			// If the field is not addressable, need to take a slower path and
-			// make a copy of the struct itself to a new location.
-			nvp := reflect.New(v.Type())
-			nvp.Elem().Set(v)
-			v = nvp.Elem()
-			_, err := d.handleKeyValuePart(key, value, v)
-			if err != nil {
-				return reflect.Value{}, err
-			}
-			return nvp.Elem(), nil
-		}
 		x, err := d.handleKeyValueInner(key, value, f)
 		if err != nil {
 			return reflect.Value{}, err
@@ -1174,10 +1137,10 @@ func initAndDereferencePointer(v reflect.Value) reflect.Value {

 // Same as reflect.Value.FieldByIndex, but creates pointers if needed.
 func fieldByIndex(v reflect.Value, path []int) reflect.Value {
-	for _, x := range path {
+	for i, x := range path {
 		v = v.Field(x)

-		if v.Kind() == reflect.Ptr {
+		if i < len(path)-1 && v.Kind() == reflect.Pointer {
 			if v.IsNil() {
 				v.Set(reflect.New(v.Type().Elem()))
 			}
@@ -1245,7 +1208,7 @@ func forEachField(t reflect.Type, path []int, do func(name string, path []int))

 		if f.Anonymous && name == "" {
 			t2 := f.Type
-			if t2.Kind() == reflect.Ptr {
+			if t2.Kind() == reflect.Pointer {
 				t2 = t2.Elem()
 			}

@@ -16,27 +16,6 @@ import (
 	"github.com/stretchr/testify/require"
 )

-type unmarshalTextKey struct {
-	A string
-	B string
-}
-
-func (k *unmarshalTextKey) UnmarshalText(text []byte) error {
-	parts := strings.Split(string(text), "-")
-	if len(parts) != 2 {
-		return fmt.Errorf("invalid text key: %s", text)
-	}
-	k.A = parts[0]
-	k.B = parts[1]
-	return nil
-}
-
-type unmarshalBadTextKey struct{}
-
-func (k *unmarshalBadTextKey) UnmarshalText(text []byte) error {
-	return fmt.Errorf("error")
-}
-
 func ExampleDecoder_DisallowUnknownFields() {
 	type S struct {
 		Key1 string
@@ -90,6 +69,7 @@ func ExampleUnmarshal() {
 	fmt.Println("version:", cfg.Version)
 	fmt.Println("name:", cfg.Name)
 	fmt.Println("tags:", cfg.Tags)
+
 	// Output:
 	// version: 2
 	// name: go-toml
@@ -240,11 +220,6 @@ func TestUnmarshal_Floats(t *testing.T) {
 			input:    `0E0`,
 			expected: 0.0,
 		},
-		{
-			desc:     "float zero without decimals",
-			input:    `0`,
-			expected: 0.0,
-		},
 		{
 			desc:     "float fractional with exponent",
 			input:    `6.626e-34`,
@@ -340,7 +315,6 @@ func TestUnmarshal(t *testing.T) {
 		target   interface{}
 		expected interface{}
 		err      bool
-		assert   func(t *testing.T, test test)
 	}
 	examples := []struct {
 		skip  bool
@@ -376,96 +350,6 @@ func TestUnmarshal(t *testing.T) {
 				}
 			},
 		},
-		{
-			desc:  "kv text key",
-			input: `a-1 = "foo"`,
-			gen: func() test {
-				type doc = map[unmarshalTextKey]string
-
-				return test{
-					target:   &doc{},
-					expected: &doc{{A: "a", B: "1"}: "foo"},
-				}
-			},
-		},
-		{
-			desc: "table text key",
-			input: `["a-1"]
-foo = "bar"`,
-			gen: func() test {
-				type doc = map[unmarshalTextKey]map[string]string
-
-				return test{
-					target:   &doc{},
-					expected: &doc{{A: "a", B: "1"}: map[string]string{"foo": "bar"}},
-				}
-			},
-		},
-		{
-			desc:  "kv ptr text key",
-			input: `a-1 = "foo"`,
-			gen: func() test {
-				type doc = map[*unmarshalTextKey]string
-
-				return test{
-					target:   &doc{},
-					expected: &doc{{A: "a", B: "1"}: "foo"},
-					assert: func(t *testing.T, test test) {
-						// Despite the documentation:
-						//     Pointer variable equality is determined based on the equality of the
-						// 		 referenced values (as opposed to the memory addresses).
-						// assert.Equal does not work properly with maps with pointer keys
-						// https://github.com/stretchr/testify/issues/1143
-						expected := make(map[unmarshalTextKey]string)
-						for k, v := range *(test.expected.(*doc)) {
-							expected[*k] = v
-						}
-						got := make(map[unmarshalTextKey]string)
-						for k, v := range *(test.target.(*doc)) {
-							got[*k] = v
-						}
-						assert.Equal(t, expected, got)
-					},
-				}
-			},
-		},
-		{
-			desc:  "kv bad text key",
-			input: `a-1 = "foo"`,
-			gen: func() test {
-				type doc = map[unmarshalBadTextKey]string
-
-				return test{
-					target: &doc{},
-					err:    true,
-				}
-			},
-		},
-		{
-			desc:  "kv bad ptr text key",
-			input: `a-1 = "foo"`,
-			gen: func() test {
-				type doc = map[*unmarshalBadTextKey]string
-
-				return test{
-					target: &doc{},
-					err:    true,
-				}
-			},
-		},
-		{
-			desc: "table bad text key",
-			input: `["a-1"]
-foo = "bar"`,
-			gen: func() test {
-				type doc = map[unmarshalBadTextKey]map[string]string
-
-				return test{
-					target: &doc{},
-					err:    true,
-				}
-			},
-		},
 		{
 			desc:  "time.time with negative zone",
 			input: `a = 1979-05-27T00:32:00-07:00 `, // space intentional
@@ -1282,64 +1166,6 @@ B = "data"`,
 				}
 			},
 		},
-		{
-			desc: "array table into maps with pointer on last key",
-			input: `[[foo]]
-			bar = "hello"`,
-			gen: func() test {
-				type doc struct {
-					Foo **[]interface{}
-				}
-				x := &[]interface{}{
-					map[string]interface{}{
-						"bar": "hello",
-					},
-				}
-				return test{
-					target: &doc{},
-					expected: &doc{
-						Foo: &x,
-					},
-				}
-			},
-		},
-		{
-			desc: "array table into maps with pointer on intermediate key",
-			input: `[[foo.foo2]]
-			bar = "hello"`,
-			gen: func() test {
-				type doc struct {
-					Foo **map[string]interface{}
-				}
-				x := &map[string]interface{}{
-					"foo2": []interface{}{
-						map[string]interface{}{
-							"bar": "hello",
-						},
-					},
-				}
-				return test{
-					target: &doc{},
-					expected: &doc{
-						Foo: &x,
-					},
-				}
-			},
-		},
-		{
-			desc: "array table into maps with pointer on last key with invalid leaf type",
-			input: `[[foo]]
-			bar = "hello"`,
-			gen: func() test {
-				type doc struct {
-					Foo **[]map[string]int
-				}
-				return test{
-					target: &doc{},
-					err:    true,
-				}
-			},
-		},
 		{
 			desc:  "unexported struct fields are ignored",
 			input: `foo = "bar"`,
@@ -1695,16 +1521,6 @@ B = "data"`,
 				}
 			},
 		},
-		{
-			desc:  "empty map into map with invalid key type",
-			input: ``,
-			gen: func() test {
-				return test{
-					target:   &map[int]string{},
-					expected: &map[int]string{},
-				}
-			},
-		},
 		{
 			desc:  "into map with convertible key type",
 			input: `A = "hello"`,
@@ -1961,12 +1777,8 @@ B = "data"`,
 				require.Error(t, err)
 			} else {
 				require.NoError(t, err)
-				if test.assert != nil {
-					test.assert(t, test)
-				} else {
 				assert.Equal(t, test.expected, test.target)
 			}
-			}
 		})
 	}
 }
@@ -2048,68 +1860,6 @@ func TestUnmarshalErrors(t *testing.T) {
 	require.Equal(t, "toml: cannot decode TOML integer into struct field toml_test.mystruct.Bar of type string", err.Error())
 }

-func TestUnmarshalStringInvalidStructField(t *testing.T) {
-	type Server struct {
-		Path string
-		Port int
-	}
-
-	type Cfg struct {
-		Server Server
-	}
-
-	var cfg Cfg
-
-	data := `[server]
-path = "/my/path"
-port = "bad"
-`
-
-	file := strings.NewReader(data)
-	err := toml.NewDecoder(file).Decode(&cfg)
-	require.Error(t, err)
-
-	x := err.(*toml.DecodeError)
-	require.Equal(t, "toml: cannot decode TOML string into struct field toml_test.Server.Port of type int", x.Error())
-	expected := `1| [server]
-2| path = "/my/path"
-3| port = "bad"
- |        ~~~~~ cannot decode TOML string into struct field toml_test.Server.Port of type int`
-
-	require.Equal(t, expected, x.String())
-}
-
-func TestUnmarshalIntegerInvalidStructField(t *testing.T) {
-	type Server struct {
-		Path string
-		Port int
-	}
-
-	type Cfg struct {
-		Server Server
-	}
-
-	var cfg Cfg
-
-	data := `[server]
-path = 100
-port = 50
-`
-
-	file := strings.NewReader(data)
-	err := toml.NewDecoder(file).Decode(&cfg)
-	require.Error(t, err)
-
-	x := err.(*toml.DecodeError)
-	require.Equal(t, "toml: cannot decode TOML integer into struct field toml_test.Server.Path of type string", x.Error())
-	expected := `1| [server]
-2| path = 100
- |        ~~~ cannot decode TOML integer into struct field toml_test.Server.Path of type string
-3| port = 50`
-
-	require.Equal(t, expected, x.String())
-}
-
 func TestUnmarshalInvalidTarget(t *testing.T) {
 	x := "foo"
 	err := toml.Unmarshal([]byte{}, x)
@@ -2716,113 +2466,6 @@ func TestIssue807(t *testing.T) {
 	require.Equal(t, "foo", m.Name)
 }

-func TestIssue850(t *testing.T) {
-	data := make(map[string]string)
-	err := toml.Unmarshal([]byte("foo = {}"), &data)
-	require.Error(t, err)
-}
-
-func TestIssue851(t *testing.T) {
-	type Target struct {
-		Params map[string]string `toml:"params"`
-	}
-
-	content := "params = {a=\"1\",b=\"2\"}"
-	var target Target
-	err := toml.Unmarshal([]byte(content), &target)
-	require.NoError(t, err)
-	require.Equal(t, map[string]string{"a": "1", "b": "2"}, target.Params)
-	err = toml.Unmarshal([]byte(content), &target)
-	require.NoError(t, err)
-	require.Equal(t, map[string]string{"a": "1", "b": "2"}, target.Params)
-}
-
-func TestIssue866(t *testing.T) {
-	type Pipeline struct {
-		Mapping map[string]struct {
-			Req [][]string `toml:"req"`
-			Res [][]string `toml:"res"`
-		} `toml:"mapping"`
-	}
-
-	type Pipelines struct {
-		PipelineMapping map[string]*Pipeline `toml:"pipelines"`
-	}
-
-	var badToml = `
-[pipelines.register]
-mapping.inst.req = [
-    ["param1", "value1"],
-]
-mapping.inst.res = [
-    ["param2", "value2"],
-]
-`
-
-	pipelines := new(Pipelines)
-	if err := toml.NewDecoder(bytes.NewBufferString(badToml)).DisallowUnknownFields().Decode(pipelines); err != nil {
-		t.Fatal(err)
-	}
-	if pipelines.PipelineMapping["register"].Mapping["inst"].Req[0][0] != "param1" {
-		t.Fatal("unmarshal failed with mismatch value")
-	}
-
-	var goodTooToml = `
-[pipelines.register]
-mapping.inst.req = [
-    ["param1", "value1"],
-]
-`
-
-	pipelines = new(Pipelines)
-	if err := toml.NewDecoder(bytes.NewBufferString(goodTooToml)).DisallowUnknownFields().Decode(pipelines); err != nil {
-		t.Fatal(err)
-	}
-	if pipelines.PipelineMapping["register"].Mapping["inst"].Req[0][0] != "param1" {
-		t.Fatal("unmarshal failed with mismatch value")
-	}
-
-	var goodToml = `
-[pipelines.register.mapping.inst]
-req = [
-    ["param1", "value1"],
-]
-res = [
-    ["param2", "value2"],
-]
-`
-
-	pipelines = new(Pipelines)
-	if err := toml.NewDecoder(bytes.NewBufferString(goodToml)).DisallowUnknownFields().Decode(pipelines); err != nil {
-		t.Fatal(err)
-	}
-	if pipelines.PipelineMapping["register"].Mapping["inst"].Req[0][0] != "param1" {
-		t.Fatal("unmarshal failed with mismatch value")
-	}
-}
-
-func TestIssue915(t *testing.T) {
-	type blah struct {
-		A string `toml:"a"`
-	}
-
-	type config struct {
-		Fizz string `toml:"fizz"`
-		blah `toml:"blah"`
-	}
-
-	b := []byte(`
-fizz = "abc"
-blah.a = "def"`)
-	var cfg config
-	err := toml.Unmarshal(b, &cfg)
-	require.NoError(t, err)
-
-	require.Equal(t, "abc", cfg.Fizz)
-	require.Equal(t, "def", cfg.blah.A)
-	require.Equal(t, "def", cfg.A)
-}
-
 func TestUnmarshalDecodeErrors(t *testing.T) {
 	examples := []struct {
 		desc string
@@ -3099,7 +2742,7 @@ world'`,
 			data: "a = \"aaaa\xE2\x80\x00\"",
 		},
 		{
-			desc: "invalid 4th byte of 4-byte utf8 character in string with no escape sequence",
+			desc: "invalid 4rd byte of 4-byte utf8 character in string with no escape sequence",
 			data: "a = \"aaaa\xF2\x81\x81\x00\"",
 		},
 		{
@@ -3115,7 +2758,7 @@ world'`,
 			data: "a = 'aaaa\xE2\x80\x00'",
 		},
 		{
-			desc: "invalid 4th byte of 4-byte utf8 character in literal string",
+			desc: "invalid 4rd byte of 4-byte utf8 character in literal string",
 			data: "a = 'aaaa\xF2\x81\x81\x00'",
 		},
 		{
@@ -3658,47 +3301,3 @@ func TestUnmarshalEmbedNonString(t *testing.T) {
 	require.NoError(t, err)
 	require.Nil(t, d.Foo)
 }
-
-func TestUnmarshal_Nil(t *testing.T) {
-	type Foo struct {
-		Foo *Foo `toml:"foo,omitempty"`
-		Bar *Foo `toml:"bar,omitempty"`
-	}
-
-	examples := []struct {
-		desc     string
-		input    string
-		expected string
-		err      bool
-	}{
-		{
-			desc:     "empty",
-			input:    ``,
-			expected: ``,
-		},
-		{
-			desc: "simplest",
-			input: `
-            [foo]
-            [foo.foo]
-            `,
-			expected: "[foo]\n[foo.foo]\n",
-		},
-	}
-
-	for _, ex := range examples {
-		e := ex
-		t.Run(e.desc, func(t *testing.T) {
-			foo := Foo{}
-			err := toml.Unmarshal([]byte(e.input), &foo)
-			if e.err {
-				require.Error(t, err)
-			} else {
-				require.NoError(t, err)
-				j, err := toml.Marshal(foo)
-				require.NoError(t, err)
-				assert.Equal(t, e.expected, string(j))
-			}
-		})
-	}
-}
@@ -1,71 +0,0 @@
-package unstable
-
-// root contains a full AST.
-//
-// It is immutable once constructed with Builder.
-type root struct {
-	nodes []Node
-}
-
-// Iterator over the top level nodes.
-func (r *root) Iterator() Iterator {
-	it := Iterator{}
-	if len(r.nodes) > 0 {
-		it.node = &r.nodes[0]
-	}
-	return it
-}
-
-func (r *root) at(idx reference) *Node {
-	return &r.nodes[idx]
-}
-
-type reference int
-
-const invalidReference reference = -1
-
-func (r reference) Valid() bool {
-	return r != invalidReference
-}
-
-type builder struct {
-	tree    root
-	lastIdx int
-}
-
-func (b *builder) Tree() *root {
-	return &b.tree
-}
-
-func (b *builder) NodeAt(ref reference) *Node {
-	return b.tree.at(ref)
-}
-
-func (b *builder) Reset() {
-	b.tree.nodes = b.tree.nodes[:0]
-	b.lastIdx = 0
-}
-
-func (b *builder) Push(n Node) reference {
-	b.lastIdx = len(b.tree.nodes)
-	b.tree.nodes = append(b.tree.nodes, n)
-	return reference(b.lastIdx)
-}
-
-func (b *builder) PushAndChain(n Node) reference {
-	newIdx := len(b.tree.nodes)
-	b.tree.nodes = append(b.tree.nodes, n)
-	if b.lastIdx >= 0 {
-		b.tree.nodes[b.lastIdx].next = newIdx - b.lastIdx
-	}
-	b.lastIdx = newIdx
-	return reference(b.lastIdx)
-}
-
-func (b *builder) AttachChild(parent reference, child reference) {
-	b.tree.nodes[parent].child = int(child) - int(parent)
-}
-
-func (b *builder) Chain(from reference, to reference) {
-	b.tree.nodes[from].next = int(to) - int(from)
-}
@@ -1,3 +0,0 @@
-// Package unstable provides APIs that do not meet the backward compatibility
-// guarantees yet.
-package unstable
@@ -1,629 +0,0 @@
-package unstable
-
-import (
-	"fmt"
-	"strconv"
-	"strings"
-	"testing"
-
-	"github.com/stretchr/testify/require"
-)
-
-func TestParser_AST_Numbers(t *testing.T) {
-	examples := []struct {
-		desc  string
-		input string
-		kind  Kind
-		err   bool
-	}{
-		{
-			desc:  "integer just digits",
-			input: `1234`,
-			kind:  Integer,
-		},
-		{
-			desc:  "integer zero",
-			input: `0`,
-			kind:  Integer,
-		},
-		{
-			desc:  "integer sign",
-			input: `+99`,
-			kind:  Integer,
-		},
-		{
-			desc:  "integer hex uppercase",
-			input: `0xDEADBEEF`,
-			kind:  Integer,
-		},
-		{
-			desc:  "integer hex lowercase",
-			input: `0xdead_beef`,
-			kind:  Integer,
-		},
-		{
-			desc:  "integer octal",
-			input: `0o01234567`,
-			kind:  Integer,
-		},
-		{
-			desc:  "integer binary",
-			input: `0b11010110`,
-			kind:  Integer,
-		},
-		{
-			desc:  "float zero",
-			input: `0.0`,
-			kind:  Float,
-		},
-		{
-			desc:  "float positive zero",
-			input: `+0.0`,
-			kind:  Float,
-		},
-		{
-			desc:  "float negative zero",
-			input: `-0.0`,
-			kind:  Float,
-		},
-		{
-			desc:  "float pi",
-			input: `3.1415`,
-			kind:  Float,
-		},
-		{
-			desc:  "float negative",
-			input: `-0.01`,
-			kind:  Float,
-		},
-		{
-			desc:  "float signed exponent",
-			input: `5e+22`,
-			kind:  Float,
-		},
-		{
-			desc:  "float exponent lowercase",
-			input: `1e06`,
-			kind:  Float,
-		},
-		{
-			desc:  "float exponent uppercase",
-			input: `-2E-2`,
-			kind:  Float,
-		},
-		{
-			desc:  "float fractional with exponent",
-			input: `6.626e-34`,
-			kind:  Float,
-		},
-		{
-			desc:  "float underscores",
-			input: `224_617.445_991_228`,
-			kind:  Float,
-		},
-		{
-			desc:  "inf",
-			input: `inf`,
-			kind:  Float,
-		},
-		{
-			desc:  "inf negative",
-			input: `-inf`,
-			kind:  Float,
-		},
-		{
-			desc:  "inf positive",
-			input: `+inf`,
-			kind:  Float,
-		},
-		{
-			desc:  "nan",
-			input: `nan`,
-			kind:  Float,
-		},
-		{
-			desc:  "nan negative",
-			input: `-nan`,
-			kind:  Float,
-		},
-		{
-			desc:  "nan positive",
-			input: `+nan`,
-			kind:  Float,
-		},
-	}
-
-	for _, e := range examples {
-		e := e
-		t.Run(e.desc, func(t *testing.T) {
-			p := Parser{}
-			p.Reset([]byte(`A = ` + e.input))
-			p.NextExpression()
-			err := p.Error()
-			if e.err {
-				require.Error(t, err)
-			} else {
-				require.NoError(t, err)
-
-				expected := astNode{
-					Kind: KeyValue,
-					Children: []astNode{
-						{Kind: e.kind, Data: []byte(e.input)},
-						{Kind: Key, Data: []byte(`A`)},
-					},
-				}
-				compareNode(t, expected, p.Expression())
-			}
-		})
-	}
-}
-
-type (
-	astNode struct {
-		Kind     Kind
-		Data     []byte
-		Children []astNode
-	}
-)
-
-func compareNode(t *testing.T, e astNode, n *Node) {
-	t.Helper()
-	require.Equal(t, e.Kind, n.Kind)
-	require.Equal(t, e.Data, n.Data)
-
-	compareIterator(t, e.Children, n.Children())
-}
-
-func compareIterator(t *testing.T, expected []astNode, actual Iterator) {
-	t.Helper()
-	idx := 0
-
-	for actual.Next() {
-		n := actual.Node()
-
-		if idx >= len(expected) {
-			t.Fatal("extra child in actual tree")
-		}
-		e := expected[idx]
-
-		compareNode(t, e, n)
-
-		idx++
-	}
-
-	if idx < len(expected) {
-		t.Fatal("missing children in actual", "idx =", idx, "expected =", len(expected))
-	}
-}
-
-//nolint:funlen
-func TestParser_AST(t *testing.T) {
-	examples := []struct {
-		desc  string
-		input string
-		ast   astNode
-		err   bool
-	}{
-		{
-			desc:  "simple string assignment",
-			input: `A = "hello"`,
-			ast: astNode{
-				Kind: KeyValue,
-				Children: []astNode{
-					{
-						Kind: String,
-						Data: []byte(`hello`),
-					},
-					{
-						Kind: Key,
-						Data: []byte(`A`),
-					},
-				},
-			},
-		},
-		{
-			desc:  "simple bool assignment",
-			input: `A = true`,
-			ast: astNode{
-				Kind: KeyValue,
-				Children: []astNode{
-					{
-						Kind: Bool,
-						Data: []byte(`true`),
-					},
-					{
-						Kind: Key,
-						Data: []byte(`A`),
-					},
-				},
-			},
-		},
-		{
-			desc:  "array of strings",
-			input: `A = ["hello", ["world", "again"]]`,
-			ast: astNode{
-				Kind: KeyValue,
-				Children: []astNode{
-					{
-						Kind: Array,
-						Children: []astNode{
-							{
-								Kind: String,
-								Data: []byte(`hello`),
-							},
-							{
-								Kind: Array,
-								Children: []astNode{
-									{
-										Kind: String,
-										Data: []byte(`world`),
-									},
-									{
-										Kind: String,
-										Data: []byte(`again`),
-									},
-								},
-							},
-						},
-					},
-					{
-						Kind: Key,
-						Data: []byte(`A`),
-					},
-				},
-			},
-		},
-		{
-			desc:  "array of arrays of strings",
-			input: `A = ["hello", "world"]`,
-			ast: astNode{
-				Kind: KeyValue,
-				Children: []astNode{
-					{
-						Kind: Array,
-						Children: []astNode{
-							{
-								Kind: String,
-								Data: []byte(`hello`),
-							},
-							{
-								Kind: String,
-								Data: []byte(`world`),
-							},
-						},
-					},
-					{
-						Kind: Key,
-						Data: []byte(`A`),
-					},
-				},
-			},
-		},
-		{
-			desc:  "inline table",
-			input: `name = { first = "Tom", last = "Preston-Werner" }`,
-			ast: astNode{
-				Kind: KeyValue,
-				Children: []astNode{
-					{
-						Kind: InlineTable,
-						Children: []astNode{
-							{
-								Kind: KeyValue,
-								Children: []astNode{
-									{Kind: String, Data: []byte(`Tom`)},
-									{Kind: Key, Data: []byte(`first`)},
-								},
-							},
-							{
-								Kind: KeyValue,
-								Children: []astNode{
-									{Kind: String, Data: []byte(`Preston-Werner`)},
-									{Kind: Key, Data: []byte(`last`)},
-								},
-							},
-						},
-					},
-					{
-						Kind: Key,
-						Data: []byte(`name`),
-					},
-				},
-			},
-		},
-	}
-
-	for _, e := range examples {
-		e := e
-		t.Run(e.desc, func(t *testing.T) {
-			p := Parser{}
-			p.Reset([]byte(e.input))
-			p.NextExpression()
-			err := p.Error()
-			if e.err {
-				require.Error(t, err)
-			} else {
-				require.NoError(t, err)
-				compareNode(t, e.ast, p.Expression())
-			}
-		})
-	}
-}
-
-func BenchmarkParseBasicStringWithUnicode(b *testing.B) {
-	p := &Parser{}
-	b.Run("4", func(b *testing.B) {
-		input := []byte(`"\u1234\u5678\u9ABC\u1234\u5678\u9ABC"`)
-		b.ReportAllocs()
-		b.SetBytes(int64(len(input)))
-
-		for i := 0; i < b.N; i++ {
-			p.parseBasicString(input)
-		}
-	})
-	b.Run("8", func(b *testing.B) {
-		input := []byte(`"\u12345678\u9ABCDEF0\u12345678\u9ABCDEF0"`)
-		b.ReportAllocs()
-		b.SetBytes(int64(len(input)))
-
-		for i := 0; i < b.N; i++ {
-			p.parseBasicString(input)
-		}
-	})
-}
-
-func BenchmarkParseBasicStringsEasy(b *testing.B) {
-	p := &Parser{}
-
-	for _, size := range []int{1, 4, 8, 16, 21} {
-		b.Run(strconv.Itoa(size), func(b *testing.B) {
-			input := []byte(`"` + strings.Repeat("A", size) + `"`)
-
-			b.ReportAllocs()
-			b.SetBytes(int64(len(input)))
-
-			for i := 0; i < b.N; i++ {
-				p.parseBasicString(input)
-			}
-		})
-	}
-}
-
-func TestParser_AST_DateTimes(t *testing.T) {
-	examples := []struct {
-		desc  string
-		input string
-		kind  Kind
-		err   bool
-	}{
-		{
-			desc:  "offset-date-time with delim 'T' and UTC offset",
-			input: `2021-07-21T12:08:05Z`,
-			kind:  DateTime,
-		},
-		{
-			desc:  "offset-date-time with space delim and +8hours offset",
-			input: `2021-07-21 12:08:05+08:00`,
-			kind:  DateTime,
-		},
-		{
-			desc:  "local-date-time with nano second",
-			input: `2021-07-21T12:08:05.666666666`,
-			kind:  LocalDateTime,
-		},
-		{
-			desc:  "local-date-time",
-			input: `2021-07-21T12:08:05`,
-			kind:  LocalDateTime,
-		},
-		{
-			desc:  "local-date",
-			input: `2021-07-21`,
-			kind:  LocalDate,
-		},
-	}
-
-	for _, e := range examples {
-		e := e
-		t.Run(e.desc, func(t *testing.T) {
-			p := Parser{}
-			p.Reset([]byte(`A = ` + e.input))
-			p.NextExpression()
-			err := p.Error()
-			if e.err {
-				require.Error(t, err)
-			} else {
-				require.NoError(t, err)
-
-				expected := astNode{
-					Kind: KeyValue,
-					Children: []astNode{
-						{Kind: e.kind, Data: []byte(e.input)},
-						{Kind: Key, Data: []byte(`A`)},
-					},
-				}
-				compareNode(t, expected, p.Expression())
-			}
-		})
-	}
-}
-
-// This example demonstrates how to parse a TOML document and preserving
-// comments.  Comments are stored in the AST as Comment nodes. This example
-// displays the structure of the full AST generated by the parser using the
-// following structure:
-//
-//  1. Each root-level expression is separated by three dashes.
-//  2. Bytes associated to a node are displayed in square brackets.
-//  3. Siblings have the same indentation.
-//  4. Children of a node are indented one level.
-func ExampleParser_comments() {
-	doc := `# Top of the document comment.
-# Optional, any amount of lines.
-
-# Above table.
-[table] # Next to table.
-# Above simple value.
-key = "value" # Next to simple value.
-# Below simple value.
-
-# Some comment alone.
-
-# Multiple comments, on multiple lines.
-
-# Above inline table.
-name = { first = "Tom", last = "Preston-Werner" } # Next to inline table.
-# Below inline table.
-
-# Above array.
-array = [ 1, 2, 3 ] # Next to one-line array.
-# Below array.
-
-# Above multi-line array.
-key5 = [ # Next to start of inline array.
-  # Second line before array content.
-  1, # Next to first element.
-  # After first element.
-  # Before second element.
-  2,
-  3, # Next to last element
-  # After last element.
-] # Next to end of array.
-# Below multi-line array.
-
-# Before array table.
-[[products]] # Next to array table.
-# After array table.
-`
-
-	var printGeneric func(*Parser, int, *Node)
-	printGeneric = func(p *Parser, indent int, e *Node) {
-		if e == nil {
-			return
-		}
-		s := p.Shape(e.Raw)
-		x := fmt.Sprintf("%d:%d->%d:%d (%d->%d)", s.Start.Line, s.Start.Column, s.End.Line, s.End.Column, s.Start.Offset, s.End.Offset)
-		fmt.Printf("%-25s | %s%s [%s]\n", x, strings.Repeat("  ", indent), e.Kind, e.Data)
-		printGeneric(p, indent+1, e.Child())
-		printGeneric(p, indent, e.Next())
-	}
-
-	printTree := func(p *Parser) {
-		for p.NextExpression() {
-			e := p.Expression()
-			fmt.Println("---")
-			printGeneric(p, 0, e)
-		}
-		if err := p.Error(); err != nil {
-			panic(err)
-		}
-	}
-
-	p := &Parser{
-		KeepComments: true,
-	}
-	p.Reset([]byte(doc))
-	printTree(p)
-
-	// Output:
-	// ---
-	// 1:1->1:31 (0->30)         | Comment [# Top of the document comment.]
-	// ---
-	// 2:1->2:33 (31->63)        | Comment [# Optional, any amount of lines.]
-	// ---
-	// 4:1->4:15 (65->79)        | Comment [# Above table.]
-	// ---
-	// 1:1->1:1 (0->0)           | Table []
-	// 5:2->5:7 (81->86)         |   Key [table]
-	// 5:9->5:25 (88->104)       | Comment [# Next to table.]
-	// ---
-	// 6:1->6:22 (105->126)      | Comment [# Above simple value.]
-	// ---
-	// 1:1->1:1 (0->0)           | KeyValue []
-	// 7:7->7:14 (133->140)      |   String [value]
-	// 7:1->7:4 (127->130)       |   Key [key]
-	// 7:15->7:38 (141->164)     | Comment [# Next to simple value.]
-	// ---
-	// 8:1->8:22 (165->186)      | Comment [# Below simple value.]
-	// ---
-	// 10:1->10:22 (188->209)    | Comment [# Some comment alone.]
-	// ---
-	// 12:1->12:40 (211->250)    | Comment [# Multiple comments, on multiple lines.]
-	// ---
-	// 14:1->14:22 (252->273)    | Comment [# Above inline table.]
-	// ---
-	// 1:1->1:1 (0->0)           | KeyValue []
-	// 15:8->15:9 (281->282)     |   InlineTable []
-	// 1:1->1:1 (0->0)           |     KeyValue []
-	// 15:18->15:23 (291->296)   |       String [Tom]
-	// 15:10->15:15 (283->288)   |       Key [first]
-	// 1:1->1:1 (0->0)           |     KeyValue []
-	// 15:32->15:48 (305->321)   |       String [Preston-Werner]
-	// 15:25->15:29 (298->302)   |       Key [last]
-	// 15:1->15:5 (274->278)     |   Key [name]
-	// 15:51->15:74 (324->347)   | Comment [# Next to inline table.]
-	// ---
-	// 16:1->16:22 (348->369)    | Comment [# Below inline table.]
-	// ---
-	// 18:1->18:15 (371->385)    | Comment [# Above array.]
-	// ---
-	// 1:1->1:1 (0->0)           | KeyValue []
-	// 1:1->1:1 (0->0)           |   Array []
-	// 19:11->19:12 (396->397)   |     Integer [1]
-	// 19:14->19:15 (399->400)   |     Integer [2]
-	// 19:17->19:18 (402->403)   |     Integer [3]
-	// 19:1->19:6 (386->391)     |   Key [array]
-	// 19:21->19:46 (406->431)   | Comment [# Next to one-line array.]
-	// ---
-	// 20:1->20:15 (432->446)    | Comment [# Below array.]
-	// ---
-	// 22:1->22:26 (448->473)    | Comment [# Above multi-line array.]
-	// ---
-	// 1:1->1:1 (0->0)           | KeyValue []
-	// 1:1->1:1 (0->0)           |   Array []
-	// 23:10->23:42 (483->515)   |     Comment [# Next to start of inline array.]
-	// 24:3->24:38 (518->553)    |       Comment [# Second line before array content.]
-	// 25:3->25:4 (556->557)     |     Integer [1]
-	// 25:6->25:30 (559->583)    |     Comment [# Next to first element.]
-	// 26:3->26:25 (586->608)    |       Comment [# After first element.]
-	// 27:3->27:27 (611->635)    |       Comment [# Before second element.]
-	// 28:3->28:4 (638->639)     |     Integer [2]
-	// 29:3->29:4 (643->644)     |     Integer [3]
-	// 29:6->29:28 (646->668)    |     Comment [# Next to last element]
-	// 30:3->30:24 (671->692)    |       Comment [# After last element.]
-	// 23:1->23:5 (474->478)     |   Key [key5]
-	// 31:3->31:26 (695->718)    | Comment [# Next to end of array.]
-	// ---
-	// 32:1->32:26 (719->744)    | Comment [# Below multi-line array.]
-	// ---
-	// 34:1->34:22 (746->767)    | Comment [# Before array table.]
-	// ---
-	// 1:1->1:1 (0->0)           | ArrayTable []
-	// 35:3->35:11 (770->778)    |   Key [products]
-	// 35:14->35:36 (781->803)   | Comment [# Next to array table.]
-	// ---
-	// 36:1->36:21 (804->824)    | Comment [# After array table.]
-}
-
-func ExampleParser() {
-	doc := `
-	hello = "world"
-	value = 42
-	`
-	p := Parser{}
-	p.Reset([]byte(doc))
-	for p.NextExpression() {
-		e := p.Expression()
-		fmt.Printf("Expression: %s\n", e.Kind)
-		value := e.Value()
-		it := e.Key()
-		k := it.Node() // shortcut: we know there is no dotted key in the example
-		fmt.Printf("%s -> (%s) %s\n", k.Data, value.Kind, value.Data)
-	}
-
-	// Output:
-	// Expression: KeyValue
-	// hello -> (String) world
-	// Expression: KeyValue
-	// value -> (Integer) 42
-}
@@ -1,4 +1,4 @@
-package characters
+package toml

 import (
 	"unicode/utf8"
@@ -32,7 +32,7 @@ func (u utf8Err) Zero() bool {
 // 0x9 => tab, ok
 // 0xA - 0x1F => invalid
 // 0x7F => invalid
-func Utf8TomlValidAlreadyEscaped(p []byte) (err utf8Err) {
+func utf8TomlValidAlreadyEscaped(p []byte) (err utf8Err) {
 	// Fast path. Check for and skip 8 bytes of ASCII characters per iteration.
 	offset := 0
 	for len(p) >= 8 {
@@ -48,7 +48,7 @@ func Utf8TomlValidAlreadyEscaped(p []byte) (err utf8Err) {
 		}

 		for i, b := range p[:8] {
-			if InvalidAscii(b) {
+			if invalidAscii(b) {
 				err.Index = offset + i
 				err.Size = 1
 				return
@@ -62,7 +62,7 @@ func Utf8TomlValidAlreadyEscaped(p []byte) (err utf8Err) {
 	for i := 0; i < n; {
 		pi := p[i]
 		if pi < utf8.RuneSelf {
-			if InvalidAscii(pi) {
+			if invalidAscii(pi) {
 				err.Index = offset + i
 				err.Size = 1
 				return
@@ -106,11 +106,11 @@ func Utf8TomlValidAlreadyEscaped(p []byte) (err utf8Err) {
 }

 // Return the size of the next rune if valid, 0 otherwise.
-func Utf8ValidNext(p []byte) int {
+func utf8ValidNext(p []byte) int {
 	c := p[0]

 	if c < utf8.RuneSelf {
-		if InvalidAscii(c) {
+		if invalidAscii(c) {
 			return 0
 		}
 		return 1
@@ -140,6 +140,47 @@ func Utf8ValidNext(p []byte) int {
 	return size
 }

+var invalidAsciiTable = [256]bool{
+	0x00: true,
+	0x01: true,
+	0x02: true,
+	0x03: true,
+	0x04: true,
+	0x05: true,
+	0x06: true,
+	0x07: true,
+	0x08: true,
+	// 0x09 TAB
+	// 0x0A LF
+	0x0B: true,
+	0x0C: true,
+	// 0x0D CR
+	0x0E: true,
+	0x0F: true,
+	0x10: true,
+	0x11: true,
+	0x12: true,
+	0x13: true,
+	0x14: true,
+	0x15: true,
+	0x16: true,
+	0x17: true,
+	0x18: true,
+	0x19: true,
+	0x1A: true,
+	0x1B: true,
+	0x1C: true,
+	0x1D: true,
+	0x1E: true,
+	0x1F: true,
+	// 0x20 - 0x7E Printable ASCII characters
+	0x7F: true,
+}
+
+func invalidAscii(b byte) bool {
+	return invalidAsciiTable[b]
+}
+
 // acceptRange gives the range of valid values for the second byte in a UTF-8
 // sequence.
 type acceptRange struct {
Author	SHA1	Message	Date
Thomas Pelletier	b371733c67	Make all nodes contain Raw	2022-08-22 21:05:41 -04:00
Thomas Pelletier	64dcce07ea	WIP	2022-08-22 23:04:44 +00:00