Multiline Marshal tag (#221)

The new multiline tag works just like the existing 'commented' tag (i.e.
`multiline:"true"`), and tells go-toml to marshal the value as a
multi-line string. The tag currently has no impact on any non-string
fields.

.gitignore

@@ -1 +1,2 @@
 test_program/test_program_bin
+fuzz/

.travis.yml

@@ -1,9 +1,9 @@
 sudo: false
 language: go
 go:
-  - 1.7.6
+  - 1.8.x
-  - 1.8.3
+  - 1.9.x
-  - 1.9
+  - 1.10.x
   - tip
 matrix:
   allow_failures:

README.md

@@ -57,9 +57,9 @@ type Config struct {
 }
 
 doc := []byte(`
-[postgres]
+[Postgres]
-user = "pelletier"
+User = "pelletier"
-password = "mypassword"`)
+Password = "mypassword"`)
 
 config := Config{}
 toml.Unmarshal(doc, &config)
@@ -114,6 +114,18 @@ You have to make sure two kind of tests run:
 
 You can run both of them using `./test.sh`.
 
+### Fuzzing
+
+The script `./fuzz.sh` is available to
+run [go-fuzz](https://github.com/dvyukov/go-fuzz) on go-toml.
+
+## Versioning
+
+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)).
+
 ## License
 
 The MIT License (MIT). Read [LICENSE](LICENSE).

cmd/tomljson/main.go

@@ -17,13 +17,12 @@ import (
 
 func main() {
 	flag.Usage = func() {
-		fmt.Fprintln(os.Stderr, `tomljson can be used in two ways:
+		fmt.Fprintln(os.Stderr, "tomljson can be used in two ways:")
-Writing to STDIN and reading from STDOUT:
+		fmt.Fprintln(os.Stderr, "Writing to STDIN and reading from STDOUT:")
-  cat file.toml | tomljson > file.json
+		fmt.Fprintln(os.Stderr, "  cat file.toml | tomljson > file.json")
-
+		fmt.Fprintln(os.Stderr, "")
-Reading from a file name:
+		fmt.Fprintln(os.Stderr, "Reading from a file name:")
-  tomljson file.toml
+		fmt.Fprintln(os.Stderr, "  tomljson file.toml")
-`)
 	}
 	flag.Parse()
 	os.Exit(processMain(flag.Args(), os.Stdin, os.Stdout, os.Stderr))

cmd/tomll/main.go

@@ -17,15 +17,14 @@ import (
 
 func main() {
 	flag.Usage = func() {
-		fmt.Fprintln(os.Stderr, `tomll can be used in two ways:
+		fmt.Fprintln(os.Stderr, "tomll can be used in two ways:")
-Writing to STDIN and reading from STDOUT:
+		fmt.Fprintln(os.Stderr, "Writing to STDIN and reading from STDOUT:")
-  cat file.toml | tomll > file.toml
+		fmt.Fprintln(os.Stderr, "  cat file.toml | tomll > file.toml")
-
+		fmt.Fprintln(os.Stderr, "")
-Reading and updating a list of files:
+		fmt.Fprintln(os.Stderr, "Reading and updating a list of files:")
-  tomll a.toml b.toml c.toml
+		fmt.Fprintln(os.Stderr, "  tomll a.toml b.toml c.toml")
-
+		fmt.Fprintln(os.Stderr, "")
-When given a list of files, tomll will modify all files in place without asking.
+		fmt.Fprintln(os.Stderr, "When given a list of files, tomll will modify all files in place without asking.")
-`)
 	}
 	flag.Parse()
 	// read from stdin and print to stdout

doc.go

@@ -17,7 +17,7 @@
 // JSONPath-like queries
 //
 // The package github.com/pelletier/go-toml/query implements a system
-// similar to JSONPath to quickly retrive elements of a TOML document using a
+// similar to JSONPath to quickly retrieve elements of a TOML document using a
 // single expression. See the package documentation for more information.
 //
 package toml

doc_test.go

@@ -61,19 +61,24 @@ func ExampleMarshal() {
 	type Postgres struct {
 		User     string `toml:"user"`
 		Password string `toml:"password"`
+		Database string `toml:"db" commented:"true" comment:"not used anymore"`
 	}
 	type Config struct {
-		Postgres Postgres `toml:"postgres"`
+		Postgres Postgres `toml:"postgres" comment:"Postgres configuration"`
 	}
 
-	config := Config{Postgres{User: "pelletier", Password: "mypassword"}}
+	config := Config{Postgres{User: "pelletier", Password: "mypassword", Database: "old_database"}}
 	b, err := toml.Marshal(config)
 	if err != nil {
 		log.Fatal(err)
 	}
 	fmt.Println(string(b))
 	// Output:
+	// # Postgres configuration
 	// [postgres]
+	//
+	//   # not used anymore
+	//   # db = "old_database"
 	//   password = "mypassword"
 	//   user = "pelletier"
 }

fuzz.go

@@ -0,0 +1,31 @@
+// +build gofuzz
+
+package toml
+
+func Fuzz(data []byte) int {
+	tree, err := LoadBytes(data)
+	if err != nil {
+		if tree != nil {
+			panic("tree must be nil if there is an error")
+		}
+		return 0
+	}
+
+	str, err := tree.ToTomlString()
+	if err != nil {
+		if str != "" {
+			panic(`str must be "" if there is an error`)
+		}
+		panic(err)
+	}
+
+	tree, err = Load(str)
+	if err != nil {
+		if tree != nil {
+			panic("tree must be nil if there is an error")
+		}
+		return 0
+	}
+
+	return 1
+}

fuzz.sh

@@ -0,0 +1,15 @@
+#! /bin/sh
+set -eu
+
+go get github.com/dvyukov/go-fuzz/go-fuzz
+go get github.com/dvyukov/go-fuzz/go-fuzz-build
+
+if [ ! -e toml-fuzz.zip ]; then
+    go-fuzz-build github.com/pelletier/go-toml
+fi
+
+rm -fr fuzz
+mkdir -p fuzz/corpus
+cp *.toml fuzz/corpus
+
+go-fuzz -bin=toml-fuzz.zip -workdir=fuzz

keysparsing.go

@@ -9,12 +9,14 @@ import (
 	"unicode"
 )
 
+// Convert the bare key group string to an array.
+// The input supports double quotation to allow "." inside the key name,
+// but escape sequences are not supported. Lexers must unescape them beforehand.
 func parseKey(key string) ([]string, error) {
 	groups := []string{}
 	var buffer bytes.Buffer
 	inQuotes := false
 	wasInQuotes := false
-	escapeNext := false
 	ignoreSpace := true
 	expectDot := false
 
@@ -25,15 +27,7 @@ func parseKey(key string) ([]string, error) {
 			}
 			ignoreSpace = false
 		}
-		if escapeNext {
-			buffer.WriteRune(char)
-			escapeNext = false
-			continue
-		}
 		switch char {
-		case '\\':
-			escapeNext = true
-			continue
 		case '"':
 			if inQuotes {
 				groups = append(groups, buffer.String())
@@ -77,9 +71,6 @@ func parseKey(key string) ([]string, error) {
 	if inQuotes {
 		return nil, errors.New("mismatched quotes")
 	}
-	if escapeNext {
-		return nil, errors.New("unfinished escape sequence")
-	}
 	if buffer.Len() > 0 {
 		groups = append(groups, buffer.String())
 	}

keysparsing_test.go

@@ -22,7 +22,10 @@ func testResult(t *testing.T, key string, expected []string) {
 }
 
 func testError(t *testing.T, key string, expectedError string) {
-	_, err := parseKey(key)
+	res, err := parseKey(key)
+	if err == nil {
+		t.Fatalf("Expected error, but succesfully parsed key %s", res)
+	}
 	if fmt.Sprintf("%s", err) != expectedError {
 		t.Fatalf("Expected error \"%s\", but got \"%s\".", expectedError, err)
 	}
@@ -47,6 +50,10 @@ func TestBaseKeyPound(t *testing.T) {
 func TestQuotedKeys(t *testing.T) {
 	testResult(t, `hello."foo".bar`, []string{"hello", "foo", "bar"})
 	testResult(t, `"hello!"`, []string{"hello!"})
+	testResult(t, `foo."ba.r".baz`, []string{"foo", "ba.r", "baz"})
+
+	// escape sequences must not be converted
+	testResult(t, `"hello\tworld"`, []string{`hello\tworld`})
 }
 
 func TestEmptyKey(t *testing.T) {

lexer.go

@@ -204,6 +204,14 @@ func (l *tomlLexer) lexRvalue() tomlLexStateFn {
 			return l.lexFalse
 		}
 
+		if l.follow("inf") {
+			return l.lexInf
+		}
+
+		if l.follow("nan") {
+			return l.lexNan
+		}
+
 		if isSpace(next) {
 			l.skip()
 			continue
@@ -265,6 +273,18 @@ func (l *tomlLexer) lexFalse() tomlLexStateFn {
 	return l.lexRvalue
 }
 
+func (l *tomlLexer) lexInf() tomlLexStateFn {
+	l.fastForward(3)
+	l.emit(tokenInf)
+	return l.lexRvalue
+}
+
+func (l *tomlLexer) lexNan() tomlLexStateFn {
+	l.fastForward(3)
+	l.emit(tokenNan)
+	return l.lexRvalue
+}
+
 func (l *tomlLexer) lexEqual() tomlLexStateFn {
 	l.next()
 	l.emit(tokenEqual)
@@ -277,6 +297,8 @@ func (l *tomlLexer) lexComma() tomlLexStateFn {
 	return l.lexRvalue
 }
 
+// Parse the key and emits its value without escape sequences.
+// bare keys, basic string keys and literal string keys are supported.
 func (l *tomlLexer) lexKey() tomlLexStateFn {
 	growingString := ""
 
@@ -287,7 +309,16 @@ func (l *tomlLexer) lexKey() tomlLexStateFn {
 			if err != nil {
 				return l.errorf(err.Error())
 			}
-			growingString += `"` + str + `"`
+			growingString += str
+			l.next()
+			continue
+		} else if r == '\'' {
+			l.next()
+			str, err := l.lexLiteralStringAsString(`'`, false)
+			if err != nil {
+				return l.errorf(err.Error())
+			}
+			growingString += str
 			l.next()
 			continue
 		} else if r == '\n' {
@@ -527,6 +558,7 @@ func (l *tomlLexer) lexTableKey() tomlLexStateFn {
 	return l.lexInsideTableKey
 }
 
+// Parse the key till "]]", but only bare keys are supported
 func (l *tomlLexer) lexInsideTableArrayKey() tomlLexStateFn {
 	for r := l.peek(); r != eof; r = l.peek() {
 		switch r {
@@ -550,6 +582,7 @@ func (l *tomlLexer) lexInsideTableArrayKey() tomlLexStateFn {
 	return l.errorf("unclosed table array key")
 }
 
+// Parse the key till "]" but only bare keys are supported
 func (l *tomlLexer) lexInsideTableKey() tomlLexStateFn {
 	for r := l.peek(); r != eof; r = l.peek() {
 		switch r {
@@ -575,11 +608,77 @@ func (l *tomlLexer) lexRightBracket() tomlLexStateFn {
 	return l.lexRvalue
 }
 
+type validRuneFn func(r rune) bool
+
+func isValidHexRune(r rune) bool {
+	return r >= 'a' && r <= 'f' ||
+		r >= 'A' && r <= 'F' ||
+		r >= '0' && r <= '9' ||
+		r == '_'
+}
+
+func isValidOctalRune(r rune) bool {
+	return r >= '0' && r <= '7' || r == '_'
+}
+
+func isValidBinaryRune(r rune) bool {
+	return r == '0' || r == '1' || r == '_'
+}
+
 func (l *tomlLexer) lexNumber() tomlLexStateFn {
 	r := l.peek()
+
+	if r == '0' {
+		follow := l.peekString(2)
+		if len(follow) == 2 {
+			var isValidRune validRuneFn
+			switch follow[1] {
+			case 'x':
+				isValidRune = isValidHexRune
+			case 'o':
+				isValidRune = isValidOctalRune
+			case 'b':
+				isValidRune = isValidBinaryRune
+			default:
+				if follow[1] >= 'a' && follow[1] <= 'z' || follow[1] >= 'A' && follow[1] <= 'Z' {
+					return l.errorf("unknown number base: %s. possible options are x (hex) o (octal) b (binary)", string(follow[1]))
+				}
+			}
+
+			if isValidRune != nil {
+				l.next()
+				l.next()
+				digitSeen := false
+				for {
+					next := l.peek()
+					if !isValidRune(next) {
+						break
+					}
+					digitSeen = true
+					l.next()
+				}
+
+				if !digitSeen {
+					return l.errorf("number needs at least one digit")
+				}
+
+				l.emit(tokenInteger)
+
+				return l.lexRvalue
+			}
+		}
+	}
+
 	if r == '+' || r == '-' {
 		l.next()
+		if l.follow("inf") {
+			return l.lexInf
+		}
+		if l.follow("nan") {
+			return l.lexNan
+		}
 	}
+
 	pointSeen := false
 	expSeen := false
 	digitSeen := false

lexer_test.go

@@ -690,7 +690,7 @@ func TestKeyGroupArray(t *testing.T) {
 
 func TestQuotedKey(t *testing.T) {
 	testFlow(t, "\"a b\" = 42", []token{
-		{Position{1, 1}, tokenKey, "\"a b\""},
+		{Position{1, 1}, tokenKey, "a b"},
 		{Position{1, 7}, tokenEqual, "="},
 		{Position{1, 9}, tokenInteger, "42"},
 		{Position{1, 11}, tokenEOF, ""},

marshal.go

@@ -4,17 +4,33 @@ import (
 	"bytes"
 	"errors"
 	"fmt"
+	"io"
 	"reflect"
+	"strconv"
 	"strings"
 	"time"
 )
 
+const tagKeyMultiline = "multiline"
+
 type tomlOpts struct {
 	name      string
+	comment   string
+	commented bool
+	multiline bool
 	include   bool
 	omitempty bool
 }
 
+type encOpts struct {
+	quoteMapKeys            bool
+	arraysOneElementPerLine bool
+}
+
+var encOptsDefaults = encOpts{
+	quoteMapKeys: false,
+}
+
 var timeType = reflect.TypeOf(time.Time{})
 var marshalerType = reflect.TypeOf(new(Marshaler)).Elem()
 
@@ -94,8 +110,15 @@ encoder, except that there is no concept of a Marshaler interface or MarshalTOML
 function for sub-structs, and currently only definite types can be marshaled
 (i.e. no `interface{}`).
 
+The following struct annotations are supported:
+
+  toml:"Field"      Overrides the field's name to output.
+  omitempty         When set, empty values and groups are not emitted.
+  comment:"comment" Emits a # comment on the same line. This supports new lines.
+  commented:"true"  Emits the value as commented.
+
 Note that pointers are automatically assigned the "omitempty" option, as TOML
-explicity does not handle null values (saying instead the label should be
+explicitly does not handle null values (saying instead the label should be
 dropped).
 
 Tree structural types and corresponding marshal types:
@@ -115,6 +138,66 @@ Tree primitive types and corresponding marshal types:
   time.Time  time.Time{}, pointers to same
 */
 func Marshal(v interface{}) ([]byte, error) {
+	return NewEncoder(nil).marshal(v)
+}
+
+// Encoder writes TOML values to an output stream.
+type Encoder struct {
+	w io.Writer
+	encOpts
+}
+
+// NewEncoder returns a new encoder that writes to w.
+func NewEncoder(w io.Writer) *Encoder {
+	return &Encoder{
+		w:       w,
+		encOpts: encOptsDefaults,
+	}
+}
+
+// Encode writes the TOML encoding of v to the stream.
+//
+// See the documentation for Marshal for details.
+func (e *Encoder) Encode(v interface{}) error {
+	b, err := e.marshal(v)
+	if err != nil {
+		return err
+	}
+	if _, err := e.w.Write(b); err != nil {
+		return err
+	}
+	return nil
+}
+
+// QuoteMapKeys sets up the encoder to encode
+// maps with string type keys with quoted TOML keys.
+//
+// This relieves the character limitations on map keys.
+func (e *Encoder) QuoteMapKeys(v bool) *Encoder {
+	e.quoteMapKeys = v
+	return e
+}
+
+// ArraysWithOneElementPerLine sets up the encoder to encode arrays
+// with more than one element on multiple lines instead of one.
+//
+// For example:
+//
+//   A = [1,2,3]
+//
+// Becomes
+//
+//   A = [
+//     1,
+//     2,
+//     3,
+//   ]
+func (e *Encoder) ArraysWithOneElementPerLine(v bool) *Encoder {
+	e.arraysOneElementPerLine = v
+	return e
+}
+
+func (e *Encoder) marshal(v interface{}) ([]byte, error) {
 	mtype := reflect.TypeOf(v)
 	if mtype.Kind() != reflect.Struct {
 		return []byte{}, errors.New("Only a struct can be marshaled to TOML")
@@ -123,18 +206,21 @@ func Marshal(v interface{}) ([]byte, error) {
 	if isCustomMarshaler(mtype) {
 		return callCustomMarshaler(sval)
 	}
-	t, err := valueToTree(mtype, sval)
+	t, err := e.valueToTree(mtype, sval)
 	if err != nil {
 		return []byte{}, err
 	}
-	s, err := t.ToTomlString()
+
-	return []byte(s), err
+	var buf bytes.Buffer
+	_, err = t.writeTo(&buf, "", "", 0, e.arraysOneElementPerLine)
+
+	return buf.Bytes(), err
 }
 
 // Convert given marshal struct or map value to toml tree
-func valueToTree(mtype reflect.Type, mval reflect.Value) (*Tree, error) {
+func (e *Encoder) valueToTree(mtype reflect.Type, mval reflect.Value) (*Tree, error) {
 	if mtype.Kind() == reflect.Ptr {
-		return valueToTree(mtype.Elem(), mval.Elem())
+		return e.valueToTree(mtype.Elem(), mval.Elem())
 	}
 	tval := newTree()
 	switch mtype.Kind() {
@@ -143,31 +229,44 @@ func valueToTree(mtype reflect.Type, mval reflect.Value) (*Tree, error) {
 			mtypef, mvalf := mtype.Field(i), mval.Field(i)
 			opts := tomlOptions(mtypef)
 			if opts.include && (!opts.omitempty || !isZero(mvalf)) {
-				val, err := valueToToml(mtypef.Type, mvalf)
+				val, err := e.valueToToml(mtypef.Type, mvalf)
 				if err != nil {
 					return nil, err
 				}
-				tval.Set(opts.name, val)
+
+				tval.SetWithOptions(opts.name, SetOptions{
+					Comment:   opts.comment,
+					Commented: opts.commented,
+					Multiline: opts.multiline,
+				}, val)
 			}
 		}
 	case reflect.Map:
 		for _, key := range mval.MapKeys() {
 			mvalf := mval.MapIndex(key)
-			val, err := valueToToml(mtype.Elem(), mvalf)
+			val, err := e.valueToToml(mtype.Elem(), mvalf)
 			if err != nil {
 				return nil, err
 			}
-			tval.Set(key.String(), val)
+			if e.quoteMapKeys {
+				keyStr, err := tomlValueStringRepresentation(key.String(), "", e.arraysOneElementPerLine)
+				if err != nil {
+					return nil, err
+				}
+				tval.SetPath([]string{keyStr}, val)
+			} else {
+				tval.Set(key.String(), val)
+			}
 		}
 	}
 	return tval, nil
 }
 
 // Convert given marshal slice to slice of Toml trees
-func valueToTreeSlice(mtype reflect.Type, mval reflect.Value) ([]*Tree, error) {
+func (e *Encoder) valueToTreeSlice(mtype reflect.Type, mval reflect.Value) ([]*Tree, error) {
 	tval := make([]*Tree, mval.Len(), mval.Len())
 	for i := 0; i < mval.Len(); i++ {
-		val, err := valueToTree(mtype.Elem(), mval.Index(i))
+		val, err := e.valueToTree(mtype.Elem(), mval.Index(i))
 		if err != nil {
 			return nil, err
 		}
@@ -177,10 +276,10 @@ func valueToTreeSlice(mtype reflect.Type, mval reflect.Value) ([]*Tree, error) {
 }
 
 // Convert given marshal slice to slice of toml values
-func valueToOtherSlice(mtype reflect.Type, mval reflect.Value) (interface{}, error) {
+func (e *Encoder) valueToOtherSlice(mtype reflect.Type, mval reflect.Value) (interface{}, error) {
 	tval := make([]interface{}, mval.Len(), mval.Len())
 	for i := 0; i < mval.Len(); i++ {
-		val, err := valueToToml(mtype.Elem(), mval.Index(i))
+		val, err := e.valueToToml(mtype.Elem(), mval.Index(i))
 		if err != nil {
 			return nil, err
 		}
@@ -190,19 +289,19 @@ func valueToOtherSlice(mtype reflect.Type, mval reflect.Value) (interface{}, err
 }
 
 // Convert given marshal value to toml value
-func valueToToml(mtype reflect.Type, mval reflect.Value) (interface{}, error) {
+func (e *Encoder) valueToToml(mtype reflect.Type, mval reflect.Value) (interface{}, error) {
 	if mtype.Kind() == reflect.Ptr {
-		return valueToToml(mtype.Elem(), mval.Elem())
+		return e.valueToToml(mtype.Elem(), mval.Elem())
 	}
 	switch {
 	case isCustomMarshaler(mtype):
 		return callCustomMarshaler(mval)
 	case isTree(mtype):
-		return valueToTree(mtype, mval)
+		return e.valueToTree(mtype, mval)
 	case isTreeSlice(mtype):
-		return valueToTreeSlice(mtype, mval)
+		return e.valueToTreeSlice(mtype, mval)
 	case isOtherSlice(mtype):
-		return valueToOtherSlice(mtype, mval)
+		return e.valueToOtherSlice(mtype, mval)
 	default:
 		switch mtype.Kind() {
 		case reflect.Bool:
@@ -227,17 +326,16 @@ func valueToToml(mtype reflect.Type, mval reflect.Value) (interface{}, error) {
 // Neither Unmarshaler interfaces nor UnmarshalTOML functions are supported for
 // sub-structs, and only definite types can be unmarshaled.
 func (t *Tree) Unmarshal(v interface{}) error {
-	mtype := reflect.TypeOf(v)
+	d := Decoder{tval: t}
-	if mtype.Kind() != reflect.Ptr || mtype.Elem().Kind() != reflect.Struct {
+	return d.unmarshal(v)
-		return errors.New("Only a pointer to struct can be unmarshaled from TOML")
+}
-	}
 
-	sval, err := valueFromTree(mtype.Elem(), t)
+// Marshal returns the TOML encoding of Tree.
-	if err != nil {
+// See Marshal() documentation for types mapping table.
-		return err
+func (t *Tree) Marshal() ([]byte, error) {
-	}
+	var buf bytes.Buffer
-	reflect.ValueOf(v).Elem().Set(sval)
+	err := NewEncoder(&buf).Encode(t)
-	return nil
+	return buf.Bytes(), err
 }
 
 // Unmarshal parses the TOML-encoded data and stores the result in the value
@@ -246,6 +344,10 @@ func (t *Tree) Unmarshal(v interface{}) error {
 // sub-structs, and currently only definite types can be unmarshaled to (i.e. no
 // `interface{}`).
 //
+// The following struct annotations are supported:
+//
+//   toml:"Field" Overrides the field's name to map to.
+//
 // See Marshal() documentation for types mapping table.
 func Unmarshal(data []byte, v interface{}) error {
 	t, err := LoadReader(bytes.NewReader(data))
@@ -255,10 +357,52 @@ func Unmarshal(data []byte, v interface{}) error {
 	return t.Unmarshal(v)
 }
 
+// Decoder reads and decodes TOML values from an input stream.
+type Decoder struct {
+	r    io.Reader
+	tval *Tree
+	encOpts
+}
+
+// NewDecoder returns a new decoder that reads from r.
+func NewDecoder(r io.Reader) *Decoder {
+	return &Decoder{
+		r:       r,
+		encOpts: encOptsDefaults,
+	}
+}
+
+// Decode reads a TOML-encoded value from it's input
+// and unmarshals it in the value pointed at by v.
+//
+// See the documentation for Marshal for details.
+func (d *Decoder) Decode(v interface{}) error {
+	var err error
+	d.tval, err = LoadReader(d.r)
+	if err != nil {
+		return err
+	}
+	return d.unmarshal(v)
+}
+
+func (d *Decoder) unmarshal(v interface{}) error {
+	mtype := reflect.TypeOf(v)
+	if mtype.Kind() != reflect.Ptr || mtype.Elem().Kind() != reflect.Struct {
+		return errors.New("Only a pointer to struct can be unmarshaled from TOML")
+	}
+
+	sval, err := d.valueFromTree(mtype.Elem(), d.tval)
+	if err != nil {
+		return err
+	}
+	reflect.ValueOf(v).Elem().Set(sval)
+	return nil
+}
+
 // Convert toml tree to marshal struct or map, using marshal type
-func valueFromTree(mtype reflect.Type, tval *Tree) (reflect.Value, error) {
+func (d *Decoder) valueFromTree(mtype reflect.Type, tval *Tree) (reflect.Value, error) {
 	if mtype.Kind() == reflect.Ptr {
-		return unwrapPointer(mtype, tval)
+		return d.unwrapPointer(mtype, tval)
 	}
 	var mval reflect.Value
 	switch mtype.Kind() {
@@ -276,7 +420,7 @@ func valueFromTree(mtype reflect.Type, tval *Tree) (reflect.Value, error) {
 						continue
 					}
 					val := tval.Get(key)
-					mvalf, err := valueFromToml(mtypef.Type, val)
+					mvalf, err := d.valueFromToml(mtypef.Type, val)
 					if err != nil {
 						return mval, formatError(err, tval.GetPosition(key))
 					}
@@ -288,8 +432,9 @@ func valueFromTree(mtype reflect.Type, tval *Tree) (reflect.Value, error) {
 	case reflect.Map:
 		mval = reflect.MakeMap(mtype)
 		for _, key := range tval.Keys() {
-			val := tval.Get(key)
+			// TODO: path splits key
-			mvalf, err := valueFromToml(mtype.Elem(), val)
+			val := tval.GetPath([]string{key})
+			mvalf, err := d.valueFromToml(mtype.Elem(), val)
 			if err != nil {
 				return mval, formatError(err, tval.GetPosition(key))
 			}
@@ -300,10 +445,10 @@ func valueFromTree(mtype reflect.Type, tval *Tree) (reflect.Value, error) {
 }
 
 // Convert toml value to marshal struct/map slice, using marshal type
-func valueFromTreeSlice(mtype reflect.Type, tval []*Tree) (reflect.Value, error) {
+func (d *Decoder) valueFromTreeSlice(mtype reflect.Type, tval []*Tree) (reflect.Value, error) {
 	mval := reflect.MakeSlice(mtype, len(tval), len(tval))
 	for i := 0; i < len(tval); i++ {
-		val, err := valueFromTree(mtype.Elem(), tval[i])
+		val, err := d.valueFromTree(mtype.Elem(), tval[i])
 		if err != nil {
 			return mval, err
 		}
@@ -313,10 +458,10 @@ func valueFromTreeSlice(mtype reflect.Type, tval []*Tree) (reflect.Value, error)
 }
 
 // Convert toml value to marshal primitive slice, using marshal type
-func valueFromOtherSlice(mtype reflect.Type, tval []interface{}) (reflect.Value, error) {
+func (d *Decoder) valueFromOtherSlice(mtype reflect.Type, tval []interface{}) (reflect.Value, error) {
 	mval := reflect.MakeSlice(mtype, len(tval), len(tval))
 	for i := 0; i < len(tval); i++ {
-		val, err := valueFromToml(mtype.Elem(), tval[i])
+		val, err := d.valueFromToml(mtype.Elem(), tval[i])
 		if err != nil {
 			return mval, err
 		}
@@ -326,117 +471,86 @@ func valueFromOtherSlice(mtype reflect.Type, tval []interface{}) (reflect.Value,
 }
 
 // Convert toml value to marshal value, using marshal type
-func valueFromToml(mtype reflect.Type, tval interface{}) (reflect.Value, error) {
+func (d *Decoder) valueFromToml(mtype reflect.Type, tval interface{}) (reflect.Value, error) {
 	if mtype.Kind() == reflect.Ptr {
-		return unwrapPointer(mtype, tval)
+		return d.unwrapPointer(mtype, tval)
 	}
-	switch {
+
-	case isTree(mtype):
+	switch tval.(type) {
-		return valueFromTree(mtype, tval.(*Tree))
+	case *Tree:
-	case isTreeSlice(mtype):
+		if isTree(mtype) {
-		return valueFromTreeSlice(mtype, tval.([]*Tree))
+			return d.valueFromTree(mtype, tval.(*Tree))
-	case isOtherSlice(mtype):
+		}
-		return valueFromOtherSlice(mtype, tval.([]interface{}))
+		return reflect.ValueOf(nil), fmt.Errorf("Can't convert %v(%T) to a tree", tval, tval)
+	case []*Tree:
+		if isTreeSlice(mtype) {
+			return d.valueFromTreeSlice(mtype, tval.([]*Tree))
+		}
+		return reflect.ValueOf(nil), fmt.Errorf("Can't convert %v(%T) to trees", tval, tval)
+	case []interface{}:
+		if isOtherSlice(mtype) {
+			return d.valueFromOtherSlice(mtype, tval.([]interface{}))
+		}
+		return reflect.ValueOf(nil), fmt.Errorf("Can't convert %v(%T) to a slice", tval, tval)
 	default:
 		switch mtype.Kind() {
-		case reflect.Bool:
+		case reflect.Bool, reflect.Struct:
-			val, ok := tval.(bool)
+			val := reflect.ValueOf(tval)
-			if !ok {
+			// if this passes for when mtype is reflect.Struct, tval is a time.Time
-				return reflect.ValueOf(nil), fmt.Errorf("Can't convert %v(%T) to bool", tval, tval)
+			if !val.Type().ConvertibleTo(mtype) {
+				return reflect.ValueOf(nil), fmt.Errorf("Can't convert %v(%T) to %v", tval, tval, mtype.String())
 			}
-			return reflect.ValueOf(val), nil
+
-		case reflect.Int:
+			return val.Convert(mtype), nil
-			val, ok := tval.(int64)
-			if !ok {
-				return reflect.ValueOf(nil), fmt.Errorf("Can't convert %v(%T) to int", tval, tval)
-			}
-			return reflect.ValueOf(int(val)), nil
-		case reflect.Int8:
-			val, ok := tval.(int64)
-			if !ok {
-				return reflect.ValueOf(nil), fmt.Errorf("Can't convert %v(%T) to int", tval, tval)
-			}
-			return reflect.ValueOf(int8(val)), nil
-		case reflect.Int16:
-			val, ok := tval.(int64)
-			if !ok {
-				return reflect.ValueOf(nil), fmt.Errorf("Can't convert %v(%T) to int", tval, tval)
-			}
-			return reflect.ValueOf(int16(val)), nil
-		case reflect.Int32:
-			val, ok := tval.(int64)
-			if !ok {
-				return reflect.ValueOf(nil), fmt.Errorf("Can't convert %v(%T) to int", tval, tval)
-			}
-			return reflect.ValueOf(int32(val)), nil
-		case reflect.Int64:
-			val, ok := tval.(int64)
-			if !ok {
-				return reflect.ValueOf(nil), fmt.Errorf("Can't convert %v(%T) to int", tval, tval)
-			}
-			return reflect.ValueOf(val), nil
-		case reflect.Uint:
-			val, ok := tval.(int64)
-			if !ok {
-				return reflect.ValueOf(nil), fmt.Errorf("Can't convert %v(%T) to uint", tval, tval)
-			}
-			return reflect.ValueOf(uint(val)), nil
-		case reflect.Uint8:
-			val, ok := tval.(int64)
-			if !ok {
-				return reflect.ValueOf(nil), fmt.Errorf("Can't convert %v(%T) to uint", tval, tval)
-			}
-			return reflect.ValueOf(uint8(val)), nil
-		case reflect.Uint16:
-			val, ok := tval.(int64)
-			if !ok {
-				return reflect.ValueOf(nil), fmt.Errorf("Can't convert %v(%T) to uint", tval, tval)
-			}
-			return reflect.ValueOf(uint16(val)), nil
-		case reflect.Uint32:
-			val, ok := tval.(int64)
-			if !ok {
-				return reflect.ValueOf(nil), fmt.Errorf("Can't convert %v(%T) to uint", tval, tval)
-			}
-			return reflect.ValueOf(uint32(val)), nil
-		case reflect.Uint64:
-			val, ok := tval.(int64)
-			if !ok {
-				return reflect.ValueOf(nil), fmt.Errorf("Can't convert %v(%T) to uint", tval, tval)
-			}
-			return reflect.ValueOf(uint64(val)), nil
-		case reflect.Float32:
-			val, ok := tval.(float64)
-			if !ok {
-				return reflect.ValueOf(nil), fmt.Errorf("Can't convert %v(%T) to float", tval, tval)
-			}
-			return reflect.ValueOf(float32(val)), nil
-		case reflect.Float64:
-			val, ok := tval.(float64)
-			if !ok {
-				return reflect.ValueOf(nil), fmt.Errorf("Can't convert %v(%T) to float", tval, tval)
-			}
-			return reflect.ValueOf(val), nil
 		case reflect.String:
-			val, ok := tval.(string)
+			val := reflect.ValueOf(tval)
-			if !ok {
+			// stupidly, int64 is convertible to string. So special case this.
-				return reflect.ValueOf(nil), fmt.Errorf("Can't convert %v(%T) to string", tval, tval)
+			if !val.Type().ConvertibleTo(mtype) || val.Kind() == reflect.Int64 {
+				return reflect.ValueOf(nil), fmt.Errorf("Can't convert %v(%T) to %v", tval, tval, mtype.String())
 			}
-			return reflect.ValueOf(val), nil
+
-		case reflect.Struct:
+			return val.Convert(mtype), nil
-			val, ok := tval.(time.Time)
+		case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
-			if !ok {
+			val := reflect.ValueOf(tval)
-				return reflect.ValueOf(nil), fmt.Errorf("Can't convert %v(%T) to time", tval, tval)
+			if !val.Type().ConvertibleTo(mtype) {
+				return reflect.ValueOf(nil), fmt.Errorf("Can't convert %v(%T) to %v", tval, tval, mtype.String())
 			}
-			return reflect.ValueOf(val), nil
+			if reflect.Indirect(reflect.New(mtype)).OverflowInt(val.Int()) {
+				return reflect.ValueOf(nil), fmt.Errorf("%v(%T) would overflow %v", tval, tval, mtype.String())
+			}
+
+			return val.Convert(mtype), nil
+		case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
+			val := reflect.ValueOf(tval)
+			if !val.Type().ConvertibleTo(mtype) {
+				return reflect.ValueOf(nil), fmt.Errorf("Can't convert %v(%T) to %v", tval, tval, mtype.String())
+			}
+			if val.Int() < 0 {
+				return reflect.ValueOf(nil), fmt.Errorf("%v(%T) is negative so does not fit in %v", tval, tval, mtype.String())
+			}
+			if reflect.Indirect(reflect.New(mtype)).OverflowUint(uint64(val.Int())) {
+				return reflect.ValueOf(nil), fmt.Errorf("%v(%T) would overflow %v", tval, tval, mtype.String())
+			}
+
+			return val.Convert(mtype), nil
+		case reflect.Float32, reflect.Float64:
+			val := reflect.ValueOf(tval)
+			if !val.Type().ConvertibleTo(mtype) {
+				return reflect.ValueOf(nil), fmt.Errorf("Can't convert %v(%T) to %v", tval, tval, mtype.String())
+			}
+			if reflect.Indirect(reflect.New(mtype)).OverflowFloat(val.Float()) {
+				return reflect.ValueOf(nil), fmt.Errorf("%v(%T) would overflow %v", tval, tval, mtype.String())
+			}
+
+			return val.Convert(mtype), nil
 		default:
-			return reflect.ValueOf(nil), fmt.Errorf("Unmarshal can't handle %v(%v)", mtype, mtype.Kind())
+			return reflect.ValueOf(nil), fmt.Errorf("Can't convert %v(%T) to %v(%v)", tval, tval, mtype, mtype.Kind())
 		}
 	}
 }
 
-func unwrapPointer(mtype reflect.Type, tval interface{}) (reflect.Value, error) {
+func (d *Decoder) unwrapPointer(mtype reflect.Type, tval interface{}) (reflect.Value, error) {
-	val, err := valueFromToml(mtype.Elem(), tval)
+	val, err := d.valueFromToml(mtype.Elem(), tval)
 	if err != nil {
 		return reflect.ValueOf(nil), err
 	}
@@ -448,7 +562,13 @@ func unwrapPointer(mtype reflect.Type, tval interface{}) (reflect.Value, error)
 func tomlOptions(vf reflect.StructField) tomlOpts {
 	tag := vf.Tag.Get("toml")
 	parse := strings.Split(tag, ",")
-	result := tomlOpts{vf.Name, true, false}
+	var comment string
+	if c := vf.Tag.Get("comment"); c != "" {
+		comment = c
+	}
+	commented, _ := strconv.ParseBool(vf.Tag.Get("commented"))
+	multiline, _ := strconv.ParseBool(vf.Tag.Get(tagKeyMultiline))
+	result := tomlOpts{name: vf.Name, comment: comment, commented: commented, multiline: multiline, include: true, omitempty: false}
 	if parse[0] != "" {
 		if parse[0] == "-" && len(parse) == 1 {
 			result.include = false

marshal_test.go

@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"io/ioutil"
 	"reflect"
+	"strings"
 	"testing"
 	"time"
 )
@@ -145,8 +146,8 @@ var docData = testDoc{
 		Second: &subdoc,
 	},
 	SubDocList: []testSubDoc{
-		testSubDoc{"List.First", 0},
+		{"List.First", 0},
-		testSubDoc{"List.Second", 0},
+		{"List.Second", 0},
 	},
 	SubDocPtrs: []*testSubDoc{&subdoc},
 }
@@ -508,6 +509,14 @@ func TestPointerUnmarshal(t *testing.T) {
 	}
 }
 
+func TestUnmarshalTypeMismatch(t *testing.T) {
+	result := pointerMarshalTestStruct{}
+	err := Unmarshal([]byte("List = 123"), &result)
+	if !strings.HasPrefix(err.Error(), "(1, 1): Can't convert 123(int64) to []string(slice)") {
+		t.Errorf("Type mismatch must be reported: got %v", err.Error())
+	}
+}
+
 type nestedMarshalTestStruct struct {
 	String [][]string
 	//Struct [][]basicMarshalTestSubStruct
@@ -521,7 +530,7 @@ var strPtr = []*string{&str1, &str2}
 var strPtr2 = []*[]*string{&strPtr}
 
 var nestedTestData = nestedMarshalTestStruct{
-	String:    [][]string{[]string{"Five", "Six"}, []string{"One", "Two"}},
+	String:    [][]string{{"Five", "Six"}, {"One", "Two"}},
 	StringPtr: &strPtr2,
 }
 
@@ -598,3 +607,200 @@ func TestNestedCustomMarshaler(t *testing.T) {
 		t.Errorf("Bad nested custom marshaler: expected\n-----\n%s\n-----\ngot\n-----\n%s\n-----\n", expected, result)
 	}
 }
+
+var commentTestToml = []byte(`
+# it's a comment on type
+[postgres]
+  # isCommented = "dvalue"
+  noComment = "cvalue"
+
+  # A comment on AttrB with a
+  # break line
+  password = "bvalue"
+
+  # A comment on AttrA
+  user = "avalue"
+
+  [[postgres.My]]
+
+    # a comment on my on typeC
+    My = "Foo"
+
+  [[postgres.My]]
+
+    # a comment on my on typeC
+    My = "Baar"
+`)
+
+func TestMarshalComment(t *testing.T) {
+	type TypeC struct {
+		My string `comment:"a comment on my on typeC"`
+	}
+	type TypeB struct {
+		AttrA string `toml:"user" comment:"A comment on AttrA"`
+		AttrB string `toml:"password" comment:"A comment on AttrB with a\n break line"`
+		AttrC string `toml:"noComment"`
+		AttrD string `toml:"isCommented" commented:"true"`
+		My    []TypeC
+	}
+	type TypeA struct {
+		TypeB TypeB `toml:"postgres" comment:"it's a comment on type"`
+	}
+
+	ta := []TypeC{{My: "Foo"}, {My: "Baar"}}
+	config := TypeA{TypeB{AttrA: "avalue", AttrB: "bvalue", AttrC: "cvalue", AttrD: "dvalue", My: ta}}
+	result, err := Marshal(config)
+	if err != nil {
+		t.Fatal(err)
+	}
+	expected := commentTestToml
+	if !bytes.Equal(result, expected) {
+		t.Errorf("Bad marshal: expected\n-----\n%s\n-----\ngot\n-----\n%s\n-----\n", expected, result)
+	}
+}
+
+type mapsTestStruct struct {
+	Simple map[string]string
+	Paths  map[string]string
+	Other  map[string]float64
+	X      struct {
+		Y struct {
+			Z map[string]bool
+		}
+	}
+}
+
+var mapsTestData = mapsTestStruct{
+	Simple: map[string]string{
+		"one plus one": "two",
+		"next":         "three",
+	},
+	Paths: map[string]string{
+		"/this/is/a/path": "/this/is/also/a/path",
+		"/heloo.txt":      "/tmp/lololo.txt",
+	},
+	Other: map[string]float64{
+		"testing": 3.9999,
+	},
+	X: struct{ Y struct{ Z map[string]bool } }{
+		Y: struct{ Z map[string]bool }{
+			Z: map[string]bool{
+				"is.Nested": true,
+			},
+		},
+	},
+}
+var mapsTestToml = []byte(`
+[Other]
+  "testing" = 3.9999
+
+[Paths]
+  "/heloo.txt" = "/tmp/lololo.txt"
+  "/this/is/a/path" = "/this/is/also/a/path"
+
+[Simple]
+  "next" = "three"
+  "one plus one" = "two"
+
+[X]
+
+  [X.Y]
+
+    [X.Y.Z]
+      "is.Nested" = true
+`)
+
+func TestEncodeQuotedMapKeys(t *testing.T) {
+	var buf bytes.Buffer
+	if err := NewEncoder(&buf).QuoteMapKeys(true).Encode(mapsTestData); err != nil {
+		t.Fatal(err)
+	}
+	result := buf.Bytes()
+	expected := mapsTestToml
+	if !bytes.Equal(result, expected) {
+		t.Errorf("Bad maps marshal: expected\n-----\n%s\n-----\ngot\n-----\n%s\n-----\n", expected, result)
+	}
+}
+
+func TestDecodeQuotedMapKeys(t *testing.T) {
+	result := mapsTestStruct{}
+	err := NewDecoder(bytes.NewBuffer(mapsTestToml)).Decode(&result)
+	expected := mapsTestData
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !reflect.DeepEqual(result, expected) {
+		t.Errorf("Bad maps unmarshal: expected %v, got %v", expected, result)
+	}
+}
+
+type structArrayNoTag struct {
+	A struct {
+		B []int64
+		C []int64
+	}
+}
+
+func TestMarshalArray(t *testing.T) {
+	expected := []byte(`
+[A]
+  B = [1,2,3]
+  C = [1]
+`)
+
+	m := structArrayNoTag{
+		A: struct {
+			B []int64
+			C []int64
+		}{
+			B: []int64{1, 2, 3},
+			C: []int64{1},
+		},
+	}
+
+	b, err := Marshal(m)
+
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if !bytes.Equal(b, expected) {
+		t.Errorf("Bad arrays marshal: expected\n-----\n%s\n-----\ngot\n-----\n%s\n-----\n", expected, b)
+	}
+}
+
+func TestMarshalArrayOnePerLine(t *testing.T) {
+	expected := []byte(`
+[A]
+  B = [
+    1,
+    2,
+    3,
+  ]
+  C = [1]
+`)
+
+	m := structArrayNoTag{
+		A: struct {
+			B []int64
+			C []int64
+		}{
+			B: []int64{1, 2, 3},
+			C: []int64{1},
+		},
+	}
+
+	var buf bytes.Buffer
+	encoder := NewEncoder(&buf).ArraysWithOneElementPerLine(true)
+	err := encoder.Encode(m)
+
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	b := buf.Bytes()
+
+	if !bytes.Equal(b, expected) {
+		t.Errorf("Bad arrays marshal: expected\n-----\n%s\n-----\ngot\n-----\n%s\n-----\n", expected, b)
+	}
+}

parser.go

@@ -5,6 +5,7 @@ package toml
 import (
 	"errors"
 	"fmt"
+	"math"
 	"reflect"
 	"regexp"
 	"strconv"
@@ -185,10 +186,7 @@ func (p *tomlParser) parseAssign() tomlParserStateFn {
 	}
 
 	// assign value to the found table
-	keyVals, err := parseKey(key.val)
+	keyVals := []string{key.val}
-	if err != nil {
-		p.raiseError(key, "%s", err)
-	}
 	if len(keyVals) != 1 {
 		p.raiseError(key, "Invalid key")
 	}
@@ -205,20 +203,32 @@ func (p *tomlParser) parseAssign() tomlParserStateFn {
 	case *Tree, []*Tree:
 		toInsert = value
 	default:
-		toInsert = &tomlValue{value, key.Position}
+		toInsert = &tomlValue{value: value, position: key.Position}
 	}
 	targetNode.values[keyVal] = toInsert
 	return p.parseStart
 }
 
 var numberUnderscoreInvalidRegexp *regexp.Regexp
+var hexNumberUnderscoreInvalidRegexp *regexp.Regexp
 
-func cleanupNumberToken(value string) (string, error) {
+func numberContainsInvalidUnderscore(value string) error {
 	if numberUnderscoreInvalidRegexp.MatchString(value) {
-		return "", errors.New("invalid use of _ in number")
+		return errors.New("invalid use of _ in number")
 	}
+	return nil
+}
+
+func hexNumberContainsInvalidUnderscore(value string) error {
+	if hexNumberUnderscoreInvalidRegexp.MatchString(value) {
+		return errors.New("invalid use of _ in hex number")
+	}
+	return nil
+}
+
+func cleanupNumberToken(value string) string {
 	cleanedVal := strings.Replace(value, "_", "", -1)
-	return cleanedVal, nil
+	return cleanedVal
 }
 
 func (p *tomlParser) parseRvalue() interface{} {
@@ -234,21 +244,57 @@ func (p *tomlParser) parseRvalue() interface{} {
 		return true
 	case tokenFalse:
 		return false
-	case tokenInteger:
+	case tokenInf:
-		cleanedVal, err := cleanupNumberToken(tok.val)
+		if tok.val[0] == '-' {
-		if err != nil {
+			return math.Inf(-1)
-			p.raiseError(tok, "%s", err)
+		}
+		return math.Inf(1)
+	case tokenNan:
+		return math.NaN()
+	case tokenInteger:
+		cleanedVal := cleanupNumberToken(tok.val)
+		var err error
+		var val int64
+		if len(cleanedVal) >= 3 && cleanedVal[0] == '0' {
+			switch cleanedVal[1] {
+			case 'x':
+				err = hexNumberContainsInvalidUnderscore(tok.val)
+				if err != nil {
+					p.raiseError(tok, "%s", err)
+				}
+				val, err = strconv.ParseInt(cleanedVal[2:], 16, 64)
+			case 'o':
+				err = numberContainsInvalidUnderscore(tok.val)
+				if err != nil {
+					p.raiseError(tok, "%s", err)
+				}
+				val, err = strconv.ParseInt(cleanedVal[2:], 8, 64)
+			case 'b':
+				err = numberContainsInvalidUnderscore(tok.val)
+				if err != nil {
+					p.raiseError(tok, "%s", err)
+				}
+				val, err = strconv.ParseInt(cleanedVal[2:], 2, 64)
+			default:
+				panic("invalid base") // the lexer should catch this first
+			}
+		} else {
+			err = numberContainsInvalidUnderscore(tok.val)
+			if err != nil {
+				p.raiseError(tok, "%s", err)
+			}
+			val, err = strconv.ParseInt(cleanedVal, 10, 64)
 		}
-		val, err := strconv.ParseInt(cleanedVal, 10, 64)
 		if err != nil {
 			p.raiseError(tok, "%s", err)
 		}
 		return val
 	case tokenFloat:
-		cleanedVal, err := cleanupNumberToken(tok.val)
+		err := numberContainsInvalidUnderscore(tok.val)
 		if err != nil {
 			p.raiseError(tok, "%s", err)
 		}
+		cleanedVal := cleanupNumberToken(tok.val)
 		val, err := strconv.ParseFloat(cleanedVal, 64)
 		if err != nil {
 			p.raiseError(tok, "%s", err)
@@ -309,7 +355,7 @@ Loop:
 			}
 			p.getToken()
 		default:
-			p.raiseError(follow, "unexpected token type in inline table: %s", follow.typ.String())
+			p.raiseError(follow, "unexpected token type in inline table: %s", follow.String())
 		}
 		previous = follow
 	}
@@ -379,5 +425,6 @@ func parseToml(flow []token) *Tree {
 }
 
 func init() {
-	numberUnderscoreInvalidRegexp = regexp.MustCompile(`([^\d]_|_[^\d]|_$|^_)`)
+	numberUnderscoreInvalidRegexp = regexp.MustCompile(`([^\d]_|_[^\d])|_$|^_`)
+	hexNumberUnderscoreInvalidRegexp = regexp.MustCompile(`(^0x_)|([^\da-f]_|_[^\da-f])|_$|^_`)
 }

parser_test.go

@@ -2,6 +2,7 @@ package toml
 
 import (
 	"fmt"
+	"math"
 	"reflect"
 	"testing"
 	"time"
@@ -72,6 +73,17 @@ func TestNumberInKey(t *testing.T) {
 	})
 }
 
+func TestIncorrectKeyExtraSquareBracket(t *testing.T) {
+	_, err := Load(`[a]b]
+zyx = 42`)
+	if err == nil {
+		t.Error("Error should have been returned.")
+	}
+	if err.Error() != "(1, 4): unexpected token" {
+		t.Error("Bad error message:", err.Error())
+	}
+}
+
 func TestSimpleNumbers(t *testing.T) {
 	tree, err := Load("a = +42\nb = -21\nc = +4.2\nd = -2.1")
 	assertTree(t, tree, err, map[string]interface{}{
@@ -82,6 +94,78 @@ func TestSimpleNumbers(t *testing.T) {
 	})
 }
 
+func TestSpecialFloats(t *testing.T) {
+	tree, err := Load(`
+normalinf = inf
+plusinf = +inf
+minusinf = -inf
+normalnan = nan
+plusnan = +nan
+minusnan = -nan
+`)
+	assertTree(t, tree, err, map[string]interface{}{
+		"normalinf": math.Inf(1),
+		"plusinf":   math.Inf(1),
+		"minusinf":  math.Inf(-1),
+		"normalnan": math.NaN(),
+		"plusnan":   math.NaN(),
+		"minusnan":  math.NaN(),
+	})
+}
+
+func TestHexIntegers(t *testing.T) {
+	tree, err := Load(`a = 0xDEADBEEF`)
+	assertTree(t, tree, err, map[string]interface{}{"a": int64(3735928559)})
+
+	tree, err = Load(`a = 0xdeadbeef`)
+	assertTree(t, tree, err, map[string]interface{}{"a": int64(3735928559)})
+
+	tree, err = Load(`a = 0xdead_beef`)
+	assertTree(t, tree, err, map[string]interface{}{"a": int64(3735928559)})
+
+	_, err = Load(`a = 0x_1`)
+	if err.Error() != "(1, 5): invalid use of _ in hex number" {
+		t.Error("Bad error message:", err.Error())
+	}
+}
+
+func TestOctIntegers(t *testing.T) {
+	tree, err := Load(`a = 0o01234567`)
+	assertTree(t, tree, err, map[string]interface{}{"a": int64(342391)})
+
+	tree, err = Load(`a = 0o755`)
+	assertTree(t, tree, err, map[string]interface{}{"a": int64(493)})
+
+	_, err = Load(`a = 0o_1`)
+	if err.Error() != "(1, 5): invalid use of _ in number" {
+		t.Error("Bad error message:", err.Error())
+	}
+}
+
+func TestBinIntegers(t *testing.T) {
+	tree, err := Load(`a = 0b11010110`)
+	assertTree(t, tree, err, map[string]interface{}{"a": int64(214)})
+
+	_, err = Load(`a = 0b_1`)
+	if err.Error() != "(1, 5): invalid use of _ in number" {
+		t.Error("Bad error message:", err.Error())
+	}
+}
+
+func TestBadIntegerBase(t *testing.T) {
+	_, err := Load(`a = 0k1`)
+	if err.Error() != "(1, 5): unknown number base: k. possible options are x (hex) o (octal) b (binary)" {
+		t.Error("Error should have been returned.")
+	}
+}
+
+func TestIntegerNoDigit(t *testing.T) {
+	_, err := Load(`a = 0b`)
+	if err.Error() != "(1, 5): number needs at least one digit" {
+		t.Error("Bad error message:", err.Error())
+	}
+}
+
 func TestNumbersWithUnderscores(t *testing.T) {
 	tree, err := Load("a = 1_000")
 	assertTree(t, tree, err, map[string]interface{}{
@@ -155,6 +239,36 @@ func TestSpaceKey(t *testing.T) {
 	})
 }
 
+func TestDoubleQuotedKey(t *testing.T) {
+	tree, err := Load(`
+	"key"        = "a"
+	"\t"         = "b"
+	"\U0001F914" = "c"
+	"\u2764"     = "d"
+	`)
+	assertTree(t, tree, err, map[string]interface{}{
+		"key":        "a",
+		"\t":         "b",
+		"\U0001F914": "c",
+		"\u2764":     "d",
+	})
+}
+
+func TestSingleQuotedKey(t *testing.T) {
+	tree, err := Load(`
+	'key'        = "a"
+	'\t'         = "b"
+	'\U0001F914' = "c"
+	'\u2764'     = "d"
+	`)
+	assertTree(t, tree, err, map[string]interface{}{
+		`key`:        "a",
+		`\t`:         "b",
+		`\U0001F914`: "c",
+		`\u2764`:     "d",
+	})
+}
+
 func TestStringEscapables(t *testing.T) {
 	tree, err := Load("a = \"a \\n b\"")
 	assertTree(t, tree, err, map[string]interface{}{
@@ -642,7 +756,7 @@ func TestTomlValueStringRepresentation(t *testing.T) {
 		{int64(12345), "12345"},
 		{uint64(50), "50"},
 		{float64(123.45), "123.45"},
-		{bool(true), "true"},
+		{true, "true"},
 		{"hello world", "\"hello world\""},
 		{"\b\t\n\f\r\"\\", "\"\\b\\t\\n\\f\\r\\\"\\\\\""},
 		{"\x05", "\"\\u0005\""},
@@ -652,7 +766,7 @@ func TestTomlValueStringRepresentation(t *testing.T) {
 			"[\"gamma\",\"delta\"]"},
 		{nil, ""},
 	} {
-		result, err := tomlValueStringRepresentation(item.Value)
+		result, err := tomlValueStringRepresentation(item.Value, "", false)
 		if err != nil {
 			t.Errorf("Test %d - unexpected error: %s", idx, err)
 		}

query/doc.go

@@ -139,7 +139,7 @@
 // Compiled Queries
 //
 // Queries may be executed directly on a Tree object, or compiled ahead
-// of time and executed discretely.  The former is more convienent, but has the
+// of time and executed discretely.  The former is more convenient, but has the
 // penalty of having to recompile the query expression each time.
 //
 //   // basic query

query/parser_test.go

@@ -2,12 +2,13 @@ package query
 
 import (
 	"fmt"
-	"github.com/pelletier/go-toml"
 	"io/ioutil"
 	"sort"
 	"strings"
 	"testing"
 	"time"
+
+	"github.com/pelletier/go-toml"
 )
 
 type queryTestNode struct {
@@ -406,8 +407,7 @@ func TestQueryFilterFn(t *testing.T) {
 
 	assertQueryPositions(t, string(buff),
 		"$..[?(float)]",
-		[]interface{}{
+		[]interface{}{ // no float values in document
-		// no float values in document
 		})
 
 	tv, _ := time.Parse(time.RFC3339, "1979-05-27T07:32:00Z")

test.sh

@@ -1,6 +1,7 @@
 #!/bin/bash
 # fail out of the script if anything here fails
 set -e
+set -o pipefail
 
 # set the path to the present working directory
 export GOPATH=`pwd`
@@ -22,9 +23,6 @@ function git_clone() {
 # Remove potential previous runs
 rm -rf src test_program_bin toml-test
 
-# Run go vet
-go vet ./...
-
 go get github.com/pelletier/go-buffruneio
 go get github.com/davecgh/go-spew/spew
 go get gopkg.in/yaml.v2

token.go

@@ -23,6 +23,8 @@ const (
 	tokenTrue
 	tokenFalse
 	tokenFloat
+	tokenInf
+	tokenNan
 	tokenEqual
 	tokenLeftBracket
 	tokenRightBracket
@@ -55,6 +57,8 @@ var tokenTypeNames = []string{
 	"True",
 	"False",
 	"Float",
+	"Inf",
+	"NaN",
 	"=",
 	"[",
 	"]",

toml.go

@@ -11,14 +11,19 @@ import (
 )
 
 type tomlValue struct {
-	value    interface{} // string, int64, uint64, float64, bool, time.Time, [] of any of this list
+	value     interface{} // string, int64, uint64, float64, bool, time.Time, [] of any of this list
-	position Position
+	comment   string
+	commented bool
+	multiline bool
+	position  Position
 }
 
 // Tree is the result of the parsing of a TOML file.
 type Tree struct {
-	values   map[string]interface{} // string -> *tomlValue, *Tree, []*Tree
+	values    map[string]interface{} // string -> *tomlValue, *Tree, []*Tree
-	position Position
+	comment   string
+	commented bool
+	position  Position
 }
 
 func newTree() *Tree {
@@ -67,18 +72,15 @@ func (t *Tree) Keys() []string {
 }
 
 // Get the value at key in the Tree.
-// Key is a dot-separated path (e.g. a.b.c).
+// Key is a dot-separated path (e.g. a.b.c) without single/double quoted strings.
+// If you need to retrieve non-bare keys, use GetPath.
 // Returns nil if the path does not exist in the tree.
 // If keys is of length zero, the current tree is returned.
 func (t *Tree) Get(key string) interface{} {
 	if key == "" {
 		return t
 	}
-	comps, err := parseKey(key)
+	return t.GetPath(strings.Split(key, "."))
-	if err != nil {
-		return nil
-	}
-	return t.GetPath(comps)
 }
 
 // GetPath returns the element in the tree indicated by 'keys'.
@@ -174,17 +176,23 @@ func (t *Tree) GetDefault(key string, def interface{}) interface{} {
 	return val
 }
 
-// Set an element in the tree.
+// SetOptions arguments are supplied to the SetWithOptions and SetPathWithOptions functions to modify marshalling behaviour.
-// Key is a dot-separated path (e.g. a.b.c).
+// The default values within the struct are valid default options.
-// Creates all necessary intermediate trees, if needed.
+type SetOptions struct {
-func (t *Tree) Set(key string, value interface{}) {
+	Comment   string
-	t.SetPath(strings.Split(key, "."), value)
+	Commented bool
+	Multiline bool
 }
 
-// SetPath sets an element in the tree.
+// SetWithOptions is the same as Set, but allows you to provide formatting
-// Keys is an array of path elements (e.g. {"a","b","c"}).
+// instructions to the key, that will be used by Marshal().
-// Creates all necessary intermediate trees, if needed.
+func (t *Tree) SetWithOptions(key string, opts SetOptions, value interface{}) {
-func (t *Tree) SetPath(keys []string, value interface{}) {
+	t.SetPathWithOptions(strings.Split(key, "."), opts, value)
+}
+
+// SetPathWithOptions is the same as SetPath, but allows you to provide
+// formatting instructions to the key, that will be reused by Marshal().
+func (t *Tree) SetPathWithOptions(keys []string, opts SetOptions, value interface{}) {
 	subtree := t
 	for _, intermediateKey := range keys[:len(keys)-1] {
 		nextTree, exists := subtree.values[intermediateKey]
@@ -209,13 +217,80 @@ func (t *Tree) SetPath(keys []string, value interface{}) {
 
 	switch value.(type) {
 	case *Tree:
+		tt := value.(*Tree)
+		tt.comment = opts.Comment
 		toInsert = value
 	case []*Tree:
 		toInsert = value
 	case *tomlValue:
-		toInsert = value
+		tt := value.(*tomlValue)
+		tt.comment = opts.Comment
+		toInsert = tt
 	default:
-		toInsert = &tomlValue{value: value}
+		toInsert = &tomlValue{value: value, comment: opts.Comment, commented: opts.Commented, multiline: opts.Multiline}
+	}
+
+	subtree.values[keys[len(keys)-1]] = toInsert
+}
+
+// Set an element in the tree.
+// Key is a dot-separated path (e.g. a.b.c).
+// Creates all necessary intermediate trees, if needed.
+func (t *Tree) Set(key string, value interface{}) {
+	t.SetWithComment(key, "", false, value)
+}
+
+// SetWithComment is the same as Set, but allows you to provide comment
+// information to the key, that will be reused by Marshal().
+func (t *Tree) SetWithComment(key string, comment string, commented bool, value interface{}) {
+	t.SetPathWithComment(strings.Split(key, "."), comment, commented, value)
+}
+
+// SetPath sets an element in the tree.
+// Keys is an array of path elements (e.g. {"a","b","c"}).
+// Creates all necessary intermediate trees, if needed.
+func (t *Tree) SetPath(keys []string, value interface{}) {
+	t.SetPathWithComment(keys, "", false, value)
+}
+
+// SetPathWithComment is the same as SetPath, but allows you to provide comment
+// information to the key, that will be reused by Marshal().
+func (t *Tree) SetPathWithComment(keys []string, comment string, commented bool, value interface{}) {
+	subtree := t
+	for _, intermediateKey := range keys[:len(keys)-1] {
+		nextTree, exists := subtree.values[intermediateKey]
+		if !exists {
+			nextTree = newTree()
+			subtree.values[intermediateKey] = nextTree // add new element here
+		}
+		switch node := nextTree.(type) {
+		case *Tree:
+			subtree = node
+		case []*Tree:
+			// go to most recent element
+			if len(node) == 0 {
+				// create element if it does not exist
+				subtree.values[intermediateKey] = append(node, newTree())
+			}
+			subtree = node[len(node)-1]
+		}
+	}
+
+	var toInsert interface{}
+
+	switch value.(type) {
+	case *Tree:
+		tt := value.(*Tree)
+		tt.comment = comment
+		toInsert = value
+	case []*Tree:
+		toInsert = value
+	case *tomlValue:
+		tt := value.(*tomlValue)
+		tt.comment = comment
+		toInsert = tt
+	default:
+		toInsert = &tomlValue{value: value, comment: comment, commented: commented}
 	}
 
 	subtree.values[keys[len(keys)-1]] = toInsert

tomltree_create.go

@@ -104,7 +104,7 @@ func sliceToTree(object interface{}) (interface{}, error) {
 		}
 		arrayValue = reflect.Append(arrayValue, reflect.ValueOf(simpleValue))
 	}
-	return &tomlValue{arrayValue.Interface(), Position{}}, nil
+	return &tomlValue{value: arrayValue.Interface(), position: Position{}}, nil
 }
 
 func toTree(object interface{}) (interface{}, error) {
@@ -127,7 +127,7 @@ func toTree(object interface{}) (interface{}, error) {
 			}
 			values[key.String()] = newValue
 		}
-		return &Tree{values, Position{}}, nil
+		return &Tree{values: values, position: Position{}}, nil
 	}
 
 	if value.Kind() == reflect.Array || value.Kind() == reflect.Slice {
@@ -138,5 +138,5 @@ func toTree(object interface{}) (interface{}, error) {
 	if err != nil {
 		return nil, err
 	}
-	return &tomlValue{simpleValue, Position{}}, nil
+	return &tomlValue{value: simpleValue, position: Position{}}, nil
 }

tomltree_create_test.go

@@ -60,7 +60,7 @@ func TestTreeCreateToTree(t *testing.T) {
 		},
 		"array":                 []string{"a", "b", "c"},
 		"array_uint":            []uint{uint(1), uint(2)},
-		"array_table":           []map[string]interface{}{map[string]interface{}{"sub_map": 52}},
+		"array_table":           []map[string]interface{}{{"sub_map": 52}},
 		"array_times":           []time.Time{time.Now(), time.Now()},
 		"map_times":             map[string]time.Time{"now": time.Now()},
 		"custom_string_map_key": map[customString]interface{}{customString("custom"): "custom"},
@@ -97,7 +97,7 @@ func TestTreeCreateToTreeInvalidArrayMemberType(t *testing.T) {
 }
 
 func TestTreeCreateToTreeInvalidTableGroupType(t *testing.T) {
-	_, err := TreeFromMap(map[string]interface{}{"foo": []map[string]interface{}{map[string]interface{}{"hello": t}}})
+	_, err := TreeFromMap(map[string]interface{}{"foo": []map[string]interface{}{{"hello": t}}})
 	expected := "cannot convert type *testing.T to Tree"
 	if err.Error() != expected {
 		t.Fatalf("expected error %s, got %s", expected, err.Error())

tomltree_write.go

@@ -12,7 +12,41 @@ import (
 	"time"
 )
 
-// encodes a string to a TOML-compliant string value
+// Encodes a string to a TOML-compliant multi-line string value
+// This function is a clone of the existing encodeTomlString function, except that whitespace characters
+// are preserved. Quotation marks and backslashes are also not escaped.
+func encodeMultilineTomlString(value string) string {
+	var b bytes.Buffer
+
+	for _, rr := range value {
+		switch rr {
+		case '\b':
+			b.WriteString(`\b`)
+		case '\t':
+			b.WriteString("\t")
+		case '\n':
+			b.WriteString("\n")
+		case '\f':
+			b.WriteString(`\f`)
+		case '\r':
+			b.WriteString("\r")
+		case '"':
+			b.WriteString(`"`)
+		case '\\':
+			b.WriteString(`\`)
+		default:
+			intRr := uint16(rr)
+			if intRr < 0x001F {
+				b.WriteString(fmt.Sprintf("\\u%0.4X", intRr))
+			} else {
+				b.WriteRune(rr)
+			}
+		}
+	}
+	return b.String()
+}
+
+// Encodes a string to a TOML-compliant string value
 func encodeTomlString(value string) string {
 	var b bytes.Buffer
 
@@ -44,7 +78,16 @@ func encodeTomlString(value string) string {
 	return b.String()
 }
 
-func tomlValueStringRepresentation(v interface{}) (string, error) {
+func tomlValueStringRepresentation(v interface{}, indent string, arraysOneElementPerLine bool) (string, error) {
+	// this interface check is added to dereference the change made in the writeTo function.
+	// That change was made to allow this function to see formatting options.
+	tv, ok := v.(*tomlValue)
+	if ok {
+		v = tv.value
+	} else {
+		tv = &tomlValue{}
+	}
+
 	switch value := v.(type) {
 	case uint64:
 		return strconv.FormatUint(value, 10), nil
@@ -54,14 +97,17 @@ func tomlValueStringRepresentation(v interface{}) (string, error) {
 		// Ensure a round float does contain a decimal point. Otherwise feeding
 		// the output back to the parser would convert to an integer.
 		if math.Trunc(value) == value {
-			return strconv.FormatFloat(value, 'f', 1, 32), nil
+			return strings.ToLower(strconv.FormatFloat(value, 'f', 1, 32)), nil
 		}
-		return strconv.FormatFloat(value, 'f', -1, 32), nil
+		return strings.ToLower(strconv.FormatFloat(value, 'f', -1, 32)), nil
 	case string:
+		if tv.multiline {
+			return "\"\"\"\n" + encodeMultilineTomlString(value) + "\"\"\"", nil
+		}
 		return "\"" + encodeTomlString(value) + "\"", nil
 	case []byte:
 		b, _ := v.([]byte)
-		return tomlValueStringRepresentation(string(b))
+		return tomlValueStringRepresentation(string(b), indent, arraysOneElementPerLine)
 	case bool:
 		if value {
 			return "true", nil
@@ -76,21 +122,38 @@ func tomlValueStringRepresentation(v interface{}) (string, error) {
 	rv := reflect.ValueOf(v)
 
 	if rv.Kind() == reflect.Slice {
-		values := []string{}
+		var values []string
 		for i := 0; i < rv.Len(); i++ {
 			item := rv.Index(i).Interface()
-			itemRepr, err := tomlValueStringRepresentation(item)
+			itemRepr, err := tomlValueStringRepresentation(item, indent, arraysOneElementPerLine)
 			if err != nil {
 				return "", err
 			}
 			values = append(values, itemRepr)
 		}
+		if arraysOneElementPerLine && len(values) > 1 {
+			stringBuffer := bytes.Buffer{}
+			valueIndent := indent + `  ` // TODO: move that to a shared encoder state
+
+			stringBuffer.WriteString("[\n")
+
+			for _, value := range values {
+				stringBuffer.WriteString(valueIndent)
+				stringBuffer.WriteString(value)
+				stringBuffer.WriteString(`,`)
+				stringBuffer.WriteString("\n")
+			}
+
+			stringBuffer.WriteString(indent + "]")
+
+			return stringBuffer.String(), nil
+		}
 		return "[" + strings.Join(values, ",") + "]", nil
 	}
 	return "", fmt.Errorf("unsupported value type %T: %v", v, v)
 }
 
-func (t *Tree) writeTo(w io.Writer, indent, keyspace string, bytesCount int64) (int64, error) {
+func (t *Tree) writeTo(w io.Writer, indent, keyspace string, bytesCount int64, arraysOneElementPerLine bool) (int64, error) {
 	simpleValuesKeys := make([]string, 0)
 	complexValuesKeys := make([]string, 0)
 
@@ -113,12 +176,29 @@ func (t *Tree) writeTo(w io.Writer, indent, keyspace string, bytesCount int64) (
 			return bytesCount, fmt.Errorf("invalid value type at %s: %T", k, t.values[k])
 		}
 
-		repr, err := tomlValueStringRepresentation(v.value)
+		repr, err := tomlValueStringRepresentation(v, indent, arraysOneElementPerLine)
 		if err != nil {
 			return bytesCount, err
 		}
 
-		writtenBytesCount, err := writeStrings(w, indent, k, " = ", repr, "\n")
+		if v.comment != "" {
+			comment := strings.Replace(v.comment, "\n", "\n"+indent+"#", -1)
+			start := "# "
+			if strings.HasPrefix(comment, "#") {
+				start = ""
+			}
+			writtenBytesCountComment, errc := writeStrings(w, "\n", indent, start, comment, "\n")
+			bytesCount += int64(writtenBytesCountComment)
+			if errc != nil {
+				return bytesCount, errc
+			}
+		}
+
+		var commented string
+		if v.commented {
+			commented = "# "
+		}
+		writtenBytesCount, err := writeStrings(w, indent, commented, k, " = ", repr, "\n")
 		bytesCount += int64(writtenBytesCount)
 		if err != nil {
 			return bytesCount, err
@@ -132,28 +212,48 @@ func (t *Tree) writeTo(w io.Writer, indent, keyspace string, bytesCount int64) (
 		if keyspace != "" {
 			combinedKey = keyspace + "." + combinedKey
 		}
+		var commented string
+		if t.commented {
+			commented = "# "
+		}
 
 		switch node := v.(type) {
 		// node has to be of those two types given how keys are sorted above
 		case *Tree:
-			writtenBytesCount, err := writeStrings(w, "\n", indent, "[", combinedKey, "]\n")
+			tv, ok := t.values[k].(*Tree)
+			if !ok {
+				return bytesCount, fmt.Errorf("invalid value type at %s: %T", k, t.values[k])
+			}
+			if tv.comment != "" {
+				comment := strings.Replace(tv.comment, "\n", "\n"+indent+"#", -1)
+				start := "# "
+				if strings.HasPrefix(comment, "#") {
+					start = ""
+				}
+				writtenBytesCountComment, errc := writeStrings(w, "\n", indent, start, comment)
+				bytesCount += int64(writtenBytesCountComment)
+				if errc != nil {
+					return bytesCount, errc
+				}
+			}
+			writtenBytesCount, err := writeStrings(w, "\n", indent, commented, "[", combinedKey, "]\n")
 			bytesCount += int64(writtenBytesCount)
 			if err != nil {
 				return bytesCount, err
 			}
-			bytesCount, err = node.writeTo(w, indent+"  ", combinedKey, bytesCount)
+			bytesCount, err = node.writeTo(w, indent+"  ", combinedKey, bytesCount, arraysOneElementPerLine)
 			if err != nil {
 				return bytesCount, err
 			}
 		case []*Tree:
 			for _, subTree := range node {
-				writtenBytesCount, err := writeStrings(w, "\n", indent, "[[", combinedKey, "]]\n")
+				writtenBytesCount, err := writeStrings(w, "\n", indent, commented, "[[", combinedKey, "]]\n")
 				bytesCount += int64(writtenBytesCount)
 				if err != nil {
 					return bytesCount, err
 				}
 
-				bytesCount, err = subTree.writeTo(w, indent+"  ", combinedKey, bytesCount)
+				bytesCount, err = subTree.writeTo(w, indent+"  ", combinedKey, bytesCount, arraysOneElementPerLine)
 				if err != nil {
 					return bytesCount, err
 				}
@@ -179,7 +279,7 @@ func writeStrings(w io.Writer, s ...string) (int, error) {
 // WriteTo encode the Tree as Toml and writes it to the writer w.
 // Returns the number of bytes written in case of success, or an error if anything happened.
 func (t *Tree) WriteTo(w io.Writer) (int64, error) {
-	return t.writeTo(w, "", "", 0)
+	return t.writeTo(w, "", "", 0, false)
 }
 
 // ToTomlString generates a human-readable representation of the current tree.

tomltree_write_test.go

@@ -30,7 +30,7 @@ func (f *failingWriter) Write(p []byte) (n int, err error) {
 
 	f.buffer.Write(p[:toWrite])
 	f.written = f.failAt
-	return toWrite, fmt.Errorf("failingWriter failed after writting %d bytes", f.written)
+	return toWrite, fmt.Errorf("failingWriter failed after writing %d bytes", f.written)
 }
 
 func assertErrorString(t *testing.T, expected string, err error) {
@@ -161,13 +161,13 @@ func TestTreeWriteToInvalidTreeSimpleValue(t *testing.T) {
 }
 
 func TestTreeWriteToInvalidTreeTomlValue(t *testing.T) {
-	tree := Tree{values: map[string]interface{}{"foo": &tomlValue{int8(1), Position{}}}}
+	tree := Tree{values: map[string]interface{}{"foo": &tomlValue{value: int8(1), comment: "", position: Position{}}}}
 	_, err := tree.ToTomlString()
 	assertErrorString(t, "unsupported value type int8: 1", err)
 }
 
 func TestTreeWriteToInvalidTreeTomlValueArray(t *testing.T) {
-	tree := Tree{values: map[string]interface{}{"foo": &tomlValue{[]interface{}{int8(1)}, Position{}}}}
+	tree := Tree{values: map[string]interface{}{"foo": &tomlValue{value: int8(1), comment: "", position: Position{}}}}
 	_, err := tree.ToTomlString()
 	assertErrorString(t, "unsupported value type int8: 1", err)
 }
@@ -176,7 +176,7 @@ func TestTreeWriteToFailingWriterInSimpleValue(t *testing.T) {
 	toml, _ := Load(`a = 2`)
 	writer := failingWriter{failAt: 0, written: 0}
 	_, err := toml.WriteTo(&writer)
-	assertErrorString(t, "failingWriter failed after writting 0 bytes", err)
+	assertErrorString(t, "failingWriter failed after writing 0 bytes", err)
 }
 
 func TestTreeWriteToFailingWriterInTable(t *testing.T) {
@@ -185,11 +185,11 @@ func TestTreeWriteToFailingWriterInTable(t *testing.T) {
 a = 2`)
 	writer := failingWriter{failAt: 2, written: 0}
 	_, err := toml.WriteTo(&writer)
-	assertErrorString(t, "failingWriter failed after writting 2 bytes", err)
+	assertErrorString(t, "failingWriter failed after writing 2 bytes", err)
 
 	writer = failingWriter{failAt: 13, written: 0}
 	_, err = toml.WriteTo(&writer)
-	assertErrorString(t, "failingWriter failed after writting 13 bytes", err)
+	assertErrorString(t, "failingWriter failed after writing 13 bytes", err)
 }
 
 func TestTreeWriteToFailingWriterInArray(t *testing.T) {
@@ -198,11 +198,11 @@ func TestTreeWriteToFailingWriterInArray(t *testing.T) {
 a = 2`)
 	writer := failingWriter{failAt: 2, written: 0}
 	_, err := toml.WriteTo(&writer)
-	assertErrorString(t, "failingWriter failed after writting 2 bytes", err)
+	assertErrorString(t, "failingWriter failed after writing 2 bytes", err)
 
 	writer = failingWriter{failAt: 15, written: 0}
 	_, err = toml.WriteTo(&writer)
-	assertErrorString(t, "failingWriter failed after writting 15 bytes", err)
+	assertErrorString(t, "failingWriter failed after writing 15 bytes", err)
 }
 
 func TestTreeWriteToMapExampleFile(t *testing.T) {
@@ -309,6 +309,24 @@ func TestTreeWriteToFloat(t *testing.T) {
 	}
 }
 
+func TestTreeWriteToSpecialFloat(t *testing.T) {
+	expected := `a = +inf
+b = -inf
+c = nan`
+
+	tree, err := Load(expected)
+	if err != nil {
+		t.Fatal(err)
+	}
+	str, err := tree.ToTomlString()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if strings.TrimSpace(str) != strings.TrimSpace(expected) {
+		t.Fatalf("Expected:\n%s\nGot:\n%s", expected, str)
+	}
+}
+
 func BenchmarkTreeToTomlString(b *testing.B) {
 	toml, err := Load(sampleHard)
 	if err != nil {