Fix key parsing in line tables (#311)

A bug was reported that indicated that inline tables did not fully support bare keys:
$ echo 'foo = { -bar => "buz"}' | ./tomljson
(1, 9): unexpected token type in inline table: Error

$ echo 'foo = { "whatever" = "buz"}' | ./tomljson
(1, 10): unexpected token type in inline table: String

echo 'foo = { _no = "buz"}' | ./tomljson
(1, 9): unexpected token type in inline table: Error

This change makes a couple of tweaks to to allow for all key variants in inline tables

Fixes: #282

lexer.go

@@ -247,13 +247,13 @@ func (l *tomlLexer) lexRvalue() tomlLexStateFn {
 func (l *tomlLexer) lexLeftCurlyBrace() tomlLexStateFn {
 	l.next()
 	l.emit(tokenLeftCurlyBrace)
-	return l.lexRvalue
+	return l.lexVoid
 }
 
 func (l *tomlLexer) lexRightCurlyBrace() tomlLexStateFn {
 	l.next()
 	l.emit(tokenRightCurlyBrace)
-	return l.lexRvalue
+	return l.lexVoid
 }
 
 func (l *tomlLexer) lexDate() tomlLexStateFn {

lexer_test.go

@@ -735,6 +735,58 @@ func TestLexUnknownRvalue(t *testing.T) {
 	})
 }
 
+func TestLexInlineTableBareKey(t *testing.T) {
+	testFlow(t, `foo = { bar = "baz" }`, []token{
+		{Position{1, 1}, tokenKey, "foo"},
+		{Position{1, 5}, tokenEqual, "="},
+		{Position{1, 7}, tokenLeftCurlyBrace, "{"},
+		{Position{1, 9}, tokenKey, "bar"},
+		{Position{1, 13}, tokenEqual, "="},
+		{Position{1, 16}, tokenString, "baz"},
+		{Position{1, 21}, tokenRightCurlyBrace, "}"},
+		{Position{1, 22}, tokenEOF, ""},
+	})
+}
+
+func TestLexInlineTableBareKeyDash(t *testing.T) {
+	testFlow(t, `foo = { -bar = "baz" }`, []token{
+		{Position{1, 1}, tokenKey, "foo"},
+		{Position{1, 5}, tokenEqual, "="},
+		{Position{1, 7}, tokenLeftCurlyBrace, "{"},
+		{Position{1, 9}, tokenKey, "-bar"},
+		{Position{1, 14}, tokenEqual, "="},
+		{Position{1, 17}, tokenString, "baz"},
+		{Position{1, 22}, tokenRightCurlyBrace, "}"},
+		{Position{1, 23}, tokenEOF, ""},
+	})
+}
+
+func TestLexInlineTableBareKeyUnderscore(t *testing.T) {
+	testFlow(t, `foo = { _bar = "baz" }`, []token{
+		{Position{1, 1}, tokenKey, "foo"},
+		{Position{1, 5}, tokenEqual, "="},
+		{Position{1, 7}, tokenLeftCurlyBrace, "{"},
+		{Position{1, 9}, tokenKey, "_bar"},
+		{Position{1, 14}, tokenEqual, "="},
+		{Position{1, 17}, tokenString, "baz"},
+		{Position{1, 22}, tokenRightCurlyBrace, "}"},
+		{Position{1, 23}, tokenEOF, ""},
+	})
+}
+
+func TestLexInlineTableQuotedKey(t *testing.T) {
+	testFlow(t, `foo = { "bar" = "baz" }`, []token{
+		{Position{1, 1}, tokenKey, "foo"},
+		{Position{1, 5}, tokenEqual, "="},
+		{Position{1, 7}, tokenLeftCurlyBrace, "{"},
+		{Position{1, 9}, tokenKey, "\"bar\""},
+		{Position{1, 15}, tokenEqual, "="},
+		{Position{1, 18}, tokenString, "baz"},
+		{Position{1, 23}, tokenRightCurlyBrace, "}"},
+		{Position{1, 24}, tokenEOF, ""},
+	})
+}
+
 func BenchmarkLexer(b *testing.B) {
 	sample := `title = "Hugo: A Fast and Flexible Website Generator"
 baseurl = "http://gohugo.io/"

parser.go

@@ -360,12 +360,15 @@ Loop:
 			}
 			key := p.getToken()
 			p.assume(tokenEqual)
-			value := p.parseRvalue()
+
-			tree.Set(key.val, value)
+			parsedKey, err := parseKey(key.val)
-		case tokenComma:
+			if err != nil {
-			if previous == nil {
+				p.raiseError(key, "invalid key: %s", err)
-				p.raiseError(follow, "inline table cannot start with a comma")
 			}
+
+			value := p.parseRvalue()
+			tree.SetPath(parsedKey, value)
+		case tokenComma:
 			if tokenIsComma(previous) {
 				p.raiseError(follow, "need field between two commas in inline table")
 			}

parser_test.go

@@ -532,6 +532,33 @@ point = { x = 1, y = 2 }`)
 	})
 }
 
+func TestInlineGroupBareKeysUnderscore(t *testing.T) {
+	tree, err := Load(`foo = { _bar = "buz" }`)
+	assertTree(t, tree, err, map[string]interface{}{
+		"foo": map[string]interface{}{
+			"_bar": "buz",
+		},
+	})
+}
+
+func TestInlineGroupBareKeysDash(t *testing.T) {
+	tree, err := Load(`foo = { -bar = "buz" }`)
+	assertTree(t, tree, err, map[string]interface{}{
+		"foo": map[string]interface{}{
+			"-bar": "buz",
+		},
+	})
+}
+
+func TestInlineGroupKeyQuoted(t *testing.T) {
+	tree, err := Load(`foo = { "bar" = "buz" }`)
+	assertTree(t, tree, err, map[string]interface{}{
+		"foo": map[string]interface{}{
+			"bar": "buz",
+		},
+	})
+}
+
 func TestExampleInlineGroupInArray(t *testing.T) {
 	tree, err := Load(`points = [{ x = 1, y = 2 }]`)
 	assertTree(t, tree, err, map[string]interface{}{
@@ -560,7 +587,7 @@ func TestInlineTableCommaExpected(t *testing.T) {
 
 func TestInlineTableCommaStart(t *testing.T) {
 	_, err := Load("foo = {, hello = 53}")
-	if err.Error() != "(1, 8): inline table cannot start with a comma" {
+	if err.Error() != "(1, 8): unexpected token type in inline table: keys cannot contain , character" {
 		t.Error("Bad error message:", err.Error())
 	}
 }
@@ -916,6 +943,13 @@ func TestMapKeyIsNum(t *testing.T) {
 	}
 }
 
+func TestInvalidKeyInlineTable(t *testing.T) {
+	_, err := Load("table={invalid..key = 1}")
+	if err.Error() != "(1, 8): invalid key: expecting key part after dot" {
+		t.Error("Bad error message:", err.Error())
+	}
+}
+
 func TestDottedKeys(t *testing.T) {
 	tree, err := Load(`
 name = "Orange"