Added a feature to run the parser without any of the built-in sanity checks (like loop checks). This improved performance, but at the risk of missing some runtime issues with the parser implementation.

Makefile

@@ -0,0 +1,5 @@
+test:
+	@(cd read; go test | grep -v ^PASS)
+	@(cd tokenize; go test | grep -v ^PASS)
+	@(cd parse; go test | grep -v ^PASS)
+	@(cd examples; go test | grep -v ^PASS)

parse/api.go

@@ -18,9 +18,22 @@ import (
 type API struct {
 	tokenAPI            *tokenize.API    // the tokenize.API, used for communicating with tokenize.Handler functions
 	result              *tokenize.Result // last tokenize.Handler result as produced by Accept() or Peek()
-	loopCheck map[string]bool  // used for parser loop detection
+	sanityChecksEnabled bool             // whether or not runtime sanity checks are enabled
+	loopCheck           map[filepos]bool // used for parser loop detection
 	err                 error            // parse error, retrieved by Error(), using API methods is denied when set
-	stopped   bool             // a boolean set to true by Stop(), using API methods is denied when true
+	stopped             bool             // a boolean set to true by Stop()
+}
+
+// DisableSanityChecks disables the built-in parser implementation sanity checks,
+// which detects parser implementation errors like loops and continuing parsing
+//  after an error or invoking Stop().
+//
+// These tests do cause a performance hit. When your parser has to handle a lot
+// of input data and is fairly complex, you might want to disable the sanity
+// checks. When you're not sure, You probably don't want to use this method,
+// and enjoy the added safety of the built-in checks.
+func (p *API) DisableSanityChecks() {
+	p.sanityChecksEnabled = true
 }
 
 // Peek checks if the upcoming input data matches the provided tokenize.Handler.
@@ -54,7 +67,7 @@ func (p *API) Accept(tokenHandler tokenize.Handler) bool {
 		forkedAPI.Merge()
 		p.result = p.tokenAPI.Result()
 		forkedAPI.Dispose()
-		if p.tokenAPI.FlushInput() {
+		if p.sanityChecksEnabled && p.tokenAPI.FlushInput() {
 			p.initLoopCheck()
 		}
 	}
@@ -62,11 +75,13 @@ func (p *API) Accept(tokenHandler tokenize.Handler) bool {
 }
 
 func (p *API) invokeHandler(name string, tokenHandler tokenize.Handler) (*tokenize.API, bool) {
+	if p.sanityChecksEnabled {
 		p.panicWhenStoppedOrInError(name)
 		p.checkForLoops(name)
 		if tokenHandler == nil {
 			callerPanic(name, "parsekit.parse.API.{name}(): {name}() called with nil tokenHandler argument at {caller}")
 		}
+	}
 
 	p.result = nil
 	p.tokenAPI.Reset()
@@ -108,7 +123,7 @@ func (p *API) IsStoppedOrInError() bool {
 // When Accept() is called, and the parser moved forward in the input data,
 // this method is called to reset the map for the new read cursor position.
 func (p *API) initLoopCheck() {
-	p.loopCheck = map[string]bool{}
+	p.loopCheck = make(map[filepos]bool)
 }
 
 // checkForLoops checks if the line of code from which Accept() or Peek()
@@ -152,9 +167,13 @@ func (p *API) Result() *tokenize.Result {
 // of this method, because it performs some sanity checks and it will return
 // an easy to use boolean indicating whether the parser can continue or not.
 func (p *API) Handle(parseHandler ...Handler) bool {
+	if p.sanityChecksEnabled {
 		p.panicWhenStoppedOrInError("Handle")
+	}
 	for _, handler := range parseHandler {
+		if p.sanityChecksEnabled {
 			p.panicWhenHandlerNil("Handle", handler)
+		}
 		handler(p)
 		if p.IsStoppedOrInError() {
 			return false
@@ -204,7 +223,9 @@ func (p *API) Error(format string, data ...interface{}) {
 // will be stopped through Stop(). Otherwise, the unexpected input is reported
 // using Expected("end of file").
 func (p *API) ExpectEndOfFile() {
+	if p.sanityChecksEnabled {
 		p.panicWhenStoppedOrInError("ExpectEndofFile")
+	}
 	if p.Peek(tokenize.A.EndOfFile) {
 		p.Stop()
 	} else {
@@ -226,7 +247,9 @@ func (p *API) ExpectEndOfFile() {
 //
 // • there was an error while reading the input.
 func (p *API) Expected(expected string) {
+	if p.sanityChecksEnabled {
 		p.panicWhenStoppedOrInError("Expected")
+	}
 	_, err := p.tokenAPI.NextRune()
 	switch {
 	case err == nil:

parse/callerinfo.go

@@ -24,10 +24,19 @@ func callerBefore(name string) string {
 	}
 }
 
-func callerFilepos(depth int) string {
+type filepos struct {
+	file string
+	line int
+}
+
+func (pos *filepos) String() string {
+	return fmt.Sprintf("%s:%d", pos.file, pos.line)
+}
+
+func callerFilepos(depth int) filepos {
 	// No error handling, because we call this method ourselves with safe depth values.
 	_, file, line, _ := runtime.Caller(depth + 1)
-	return fmt.Sprintf("%s:%d", file, line)
+	return filepos{file, line}
 }
 
 func callerPanic(name, f string, data ...interface{}) {

parse/parse.go

@@ -26,13 +26,31 @@ type Func func(interface{}) error
 // against the provided input data. For an overview of allowed inputs, take a
 // look at the documentation for parsekit.read.New().
 func New(startHandler Handler) Func {
+	return new(startHandler, true)
+}
+
+// NewWithoutSanityChecks instantiates a new parser, which does not have
+// parsekit's built-in sanith checks enabled (e.g. checks for loops or
+// or calls to parse.API methods after an error or Stop()).
+//
+// Disabling sanity checks does improve parsing performance, but for
+// most use cases this is not an issue. Only disable sanity checks when
+// you really need the extra performance.
+// You can of course create a normal sanity-checked parser that is used
+// during development / unit testing, and an unchecked one for production.
+func NewWithoutSanityChecks(startHandler Handler) Func {
+	return new(startHandler, false)
+}
+
+func new(startHandler Handler, sanityChecksEnabled bool) Func {
 	if startHandler == nil {
 		callerPanic("New", "parsekit.parse.{name}(): {name}() called with nil input at {caller}")
 	}
 	return func(input interface{}) error {
 		api := &API{
 			tokenAPI:            tokenize.NewAPI(input),
-			loopCheck: map[string]bool{},
+			loopCheck:           make(map[filepos]bool),
+			sanityChecksEnabled: sanityChecksEnabled,
 		}
 		if api.Handle(startHandler) {
 			// Handle returned true, indicating that parsing could still continue.