A few small changes used for TOML support.

parse/api.go

@@ -191,10 +191,10 @@ func (p *API) Stop() {
 // After setting an error, no more calls to API methods are allowed.
 // Calling a method in this state will result in a panic.
 // TODO ... wait how do I read the error? I don't I guess, I just return it. Is Error() a good name or SetError() better for example?
-func (p *API) Error(format string, args ...interface{}) {
+func (p *API) Error(format string, data ...interface{}) {
 	// No call to p.panicWhenStoppedOrInError(), to allow a parser to
 	// set a different error message when needed.
-	message := fmt.Sprintf(format, args...)
+	message := fmt.Sprintf(format, data...)
 	p.err = fmt.Errorf("%s at %s", message, *p.tokenAPI.Result().Cursor())
 }
 

parse/callerinfo.go

@@ -30,9 +30,9 @@ func callerFilepos(depth int) string {
 	return fmt.Sprintf("%s:%d", file, line)
 }
 
-func callerPanic(name, f string, args ...interface{}) {
+func callerPanic(name, f string, data ...interface{}) {
 	filepos := callerBefore(name)
-	m := fmt.Sprintf(f, args...)
+	m := fmt.Sprintf(f, data...)
 	m = strings.Replace(m, "{caller}", filepos, -1)
 	m = strings.Replace(m, "{name}", name, -1)
 	panic(m)

tokenize/callerinfo.go

@@ -6,9 +6,9 @@ import (
 	"strings"
 )
 
-func callerPanic(name, f string, args ...interface{}) {
+func callerPanic(name, f string, data ...interface{}) {
 	filepos := callerBefore(name)
-	m := fmt.Sprintf(f, args...)
+	m := fmt.Sprintf(f, data...)
 	m = strings.Replace(m, "{caller}", filepos, -1)
 	m = strings.Replace(m, "{name}", name, -1)
 	panic(m)

tokenize/handlers_builtin.go

@@ -128,6 +128,7 @@ var A = struct {
 	Digit          Handler
 	DigitNotZero   Handler
 	Digits         Handler
+	Zero           Handler
 	Float          Handler
 	Boolean        Handler
 	Integer        Handler
@@ -211,6 +212,7 @@ var A = struct {
 	Digit:          MatchDigit(),
 	DigitNotZero:   MatchDigitNotZero(),
 	Digits:         MatchDigits(),
+	Zero:           MatchRune('0'),
 	Integer:        MatchInteger(),
 	Signed:         MatchSigned,
 	IntegerBetween: MatchIntegerBetween,
@@ -324,7 +326,7 @@ func MatchRune(expected rune) Handler {
 }
 
 // MatchRunes creates a Handler function that checks if the input matches
-// one of the provided runes.
+// one of the provided runes. The first match counts.
 func MatchRunes(expected ...rune) Handler {
 	s := string(expected)
 	return MatchRuneByCallback(func(r rune) bool { return strings.ContainsRune(s, r) })