Backup changes for performance fixes.

parse/api.go

@@ -19,7 +19,7 @@ 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()
 	sanityChecksEnabled bool             // whether or not runtime sanity checks are enabled
-	loopCheck           map[filepos]bool // used for parser loop detection
+	loopCheck           map[uintptr]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()
 }
@@ -125,14 +125,14 @@ 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 = make(map[filepos]bool)
+	p.loopCheck = make(map[uintptr]bool)
 }
 
 // checkForLoops checks if the line of code from which Accept() or Peek()
 // was called has been seen before for the current read cursor position.
 // If yes, then the parser is in a loop and the method will panic.
 func (p *API) checkForLoops(name string) {
-	filepos := callerFilepos(3)
+	filepos := callerPointer(3)
 	if _, ok := p.loopCheck[filepos]; ok {
 		callerPanic(name, "parsekit.parse.API.{name}(): Loop detected in parser at {caller}")
 	}

parse/callerinfo.go

@@ -39,6 +39,12 @@ func callerFilepos(depth int) filepos {
 	return filepos{file, line}
 }
 
+func callerPointer(depth int) uintptr {
+	// No error handling, because we call this method ourselves with safe depth values.
+	p, _, _, _ := runtime.Caller(depth + 1)
+	return p
+}
+
 func callerPanic(name, f string, data ...interface{}) {
 	filepos := callerBefore(name)
 	m := fmt.Sprintf(f, data...)

parse/parse.go

@@ -49,7 +49,7 @@ func new(startHandler Handler, sanityChecksEnabled bool) Func {
 	return func(input interface{}) error {
 		api := &API{
 			tokenAPI:            tokenize.NewAPI(input),
-			loopCheck:           make(map[filepos]bool),
+			loopCheck:           make(map[uintptr]bool),
 			sanityChecksEnabled: sanityChecksEnabled,
 		}
 		if api.Handle(startHandler) {

read/assertions_test.go

@@ -1,4 +1,4 @@
-package read_test
+package read
 
 // This file contains some tools that are used for writing tests.
 
@@ -8,11 +8,18 @@ import (
 	"testing"
 )
 
-func AssertEqual(t *testing.T, expected interface{}, actual interface{}) {
+func assertEqual(t *testing.T, expected interface{}, actual interface{}) {
 	if expected != actual {
+		switch expected.(type) {
+		case rune:
 			t.Errorf(
 				"Unexpected value at %s:\nexpected: %q\nactual: %q",
 				callerFilepos(1), expected, actual)
+		default:
+			t.Errorf(
+				"Unexpected value at %s:\nexpected: %v\nactual: %v",
+				callerFilepos(1), expected, actual)
+		}
 	}
 }
 
@@ -22,7 +29,7 @@ func callerFilepos(depth int) string {
 	return fmt.Sprintf("%s:%d", file, line)
 }
 
-func AssertPanic(t *testing.T, code func(), expected string) {
+func assertPanic(t *testing.T, code func(), expected string) {
 	defer func() {
 		if r := recover(); r != nil {
 			if expected != r.(string) {
@@ -36,3 +43,19 @@ func AssertPanic(t *testing.T, code func(), expected string) {
 	}()
 	code()
 }
+
+func assertCache(t *testing.T, name string, r *Buffer, code func(), storeLen, storeCap, bufLen, bufCap int) {
+	code()
+	if storeLen != len(r.store) {
+		t.Errorf("[%s] Unexpected store len (expected %d, got %d)", name, storeLen, len(r.store))
+	}
+	if storeCap != cap(r.store) {
+		t.Errorf("[%s] Unexpected store cap (expected %d, got %d)", name, storeCap, cap(r.store))
+	}
+	if bufLen != len(r.buffer) {
+		t.Errorf("[%s] Unexpected buffer len (expected %d, got %d)", name, bufLen, len(r.buffer))
+	}
+	if bufCap != cap(r.buffer) {
+		t.Errorf("[%s] Unexpected buffer cap (expected %d, got %d)", name, bufCap, cap(r.buffer))
+	}
+}

read/read.go

@@ -151,7 +151,6 @@ func (r *Buffer) RuneAt(offset int) (rune, error) {
 			r.buffer[writeAt] = readRune
 		}
 	}
-
 	return r.buffer[offset], nil
 }
 
@@ -173,29 +172,40 @@ func (r *Buffer) grow(n int) {
 		if b < n {
 			b = n
 		}
-		r.store = make([]rune, n, b)
+		r.store = make([]rune, 0, b)
-		r.buffer = r.store
+		r.buffer = r.store[:n]
 		return
 	}
-	l := len(r.buffer)
+
-	c := cap(r.buffer)
+	lenBuffer := len(r.buffer)
+	capBuffer := cap(r.buffer)
+	freeBuffer := capBuffer - lenBuffer
+	newSize := lenBuffer + n
+
 	// Grow the buffer store by reslicing within the available capacity.
-	if n <= c-l {
+	if freeBuffer >= n {
-		r.buffer = r.buffer[:l+n]
+		r.buffer = r.buffer[:newSize]
 		return
 	}
+
+	capStore := cap(r.store)
+	freeAtStartOfStore := capStore - capBuffer
+
 	// Grow the buffer by moving the data to the start of the store.
-	if cap(r.store)-l-n > 0 {
+	// Note: according to the spec, overlapping slices are allowed with copy().
+	if freeAtStartOfStore > 0 && newSize <= capStore {
+		r.store = r.store[0:newSize]
 		copy(r.store, r.buffer)
-		r.buffer = r.store[:l+n]
+		r.buffer = r.store[:newSize]
+		r.store = r.store[:0]
 		return
 	}
+
 	// Grow the buffer store by allocating a new one and copying the data.
-	buf := makeSlice(2*cap(r.store) + n)
+	buf := makeSlice(2*capStore + n)
-	fmt.Printf("ALLOC %d\n", 2*cap(r.store)+n)
 	copy(buf, r.buffer)
 	r.store = buf
-	r.buffer = r.store[:l+n]
+	r.buffer = r.store[:newSize]
 }
 
 // makeSlice allocates a slice of size n. If the allocation fails, it panics
@@ -207,7 +217,7 @@ func makeSlice(n int) []rune {
 			panic(ErrTooLarge)
 		}
 	}()
-	return make([]rune, n)
+	return make([]rune, 0, n)
 }
 
 // Flush deletes the provided number of runes from the start of the Buffer.

read/read_test.go

@@ -1,4 +1,4 @@
-package read_test
+package read
 
 import (
 	"bufio"
@@ -7,13 +7,11 @@ import (
 	"strings"
 	"testing"
 	"unicode/utf8"
-
-	"git.makaay.nl/mauricem/go-parsekit/read"
 )
 
 func ExampleNew() {
 	printFirstRuneOf := func(input interface{}) {
-		r := read.New(input)
+		r := New(input)
 		c, _ := r.RuneAt(0)
 		fmt.Printf("%q\n", c)
 	}
@@ -47,7 +45,7 @@ func TestNew_VariousInputTypesCanBeUsed(t *testing.T) {
 		{"*bufio.Reader", bufio.NewReader(strings.NewReader("Hello, world!"))},
 		{"bufio.Reader", *(bufio.NewReader(strings.NewReader("Hello, world!")))},
 	} {
-		r := read.New(test.input)
+		r := New(test.input)
 		firstRune, _ := r.RuneAt(0)
 		if firstRune != 'H' {
 			t.Errorf("[%s] first rune not 'H'", test.name)
@@ -60,42 +58,42 @@ func TestNew_VariousInputTypesCanBeUsed(t *testing.T) {
 }
 
 func TestNew_UnhandledInputType_Panics(t *testing.T) {
-	AssertPanic(t,
+	assertPanic(t,
-		func() { read.New(12345) },
+		func() { New(12345) },
 		"parsekit.read.New(): no support for input of type int")
 }
 
 func TestBuffer_RuneAt(t *testing.T) {
-	r := read.New(strings.NewReader("Hello, world!"))
+	r := New(strings.NewReader("Hello, world!"))
 	at := func(i int) rune { r, _ := r.RuneAt(i); return r }
 
 	// It is possible to go back and forth while reading the input.
 	result := fmt.Sprintf("%c%c%c%c", at(0), at(12), at(7), at(0))
-	AssertEqual(t, "H!wH", result)
+	assertEqual(t, "H!wH", result)
 }
 
 func TestBuffer_RuneAt_endOfFile(t *testing.T) {
-	r := read.New(strings.NewReader("Hello, world!"))
+	r := New(strings.NewReader("Hello, world!"))
 
 	rn, err := r.RuneAt(13)
 	result := fmt.Sprintf("%q %s %t", rn, err, err == io.EOF)
-	AssertEqual(t, "'<27>' EOF true", result)
+	assertEqual(t, "'<27>' EOF true", result)
 
 	rn, err = r.RuneAt(20)
 	result = fmt.Sprintf("%q %s %t", rn, err, err == io.EOF)
-	AssertEqual(t, "'<27>' EOF true", result)
+	assertEqual(t, "'<27>' EOF true", result)
 }
 
 func TestBuffer_RuneAt_invalidRune(t *testing.T) {
-	r := read.New(strings.NewReader("Hello, \xcdworld!"))
+	r := New(strings.NewReader("Hello, \xcdworld!"))
 	at := func(i int) rune { r, _ := r.RuneAt(i); return r }
 
 	result := fmt.Sprintf("%c%c%c%c", at(6), at(7), at(8), at(9))
-	AssertEqual(t, " <20>wo", result)
+	assertEqual(t, " <20>wo", result)
 }
 
 func ExampleBuffer_RuneAt() {
-	reader := read.New(strings.NewReader("Hello, world!"))
+	reader := New(strings.NewReader("Hello, world!"))
 
 	fmt.Printf("Runes: ")
 	for i := 0; ; i++ {
@@ -113,21 +111,21 @@ func ExampleBuffer_RuneAt() {
 }
 
 func TestRuneAt_SkipsBOMAtStartOfFile(t *testing.T) {
-	r := read.New(strings.NewReader("\uFEFFBommetje!"))
+	r := New(strings.NewReader("\uFEFFBommetje!"))
 	b, _ := r.RuneAt(0)
 	o, _ := r.RuneAt(1)
 	m, _ := r.RuneAt(2)
 	bom := fmt.Sprintf("%c%c%c", b, o, m)
-	AssertEqual(t, "Bom", bom)
+	assertEqual(t, "Bom", bom)
 }
 
 func TestBuffer_Flush(t *testing.T) {
-	r := read.New(strings.NewReader("Hello, world!"))
+	r := New(strings.NewReader("Hello, world!"))
 	at := func(i int) rune { r, _ := r.RuneAt(i); return r }
 
 	// Fills the buffer with the first 8 runes on the input: "Hello, w"
 	result := fmt.Sprintf("%c", at(7))
-	AssertEqual(t, "w", result)
+	assertEqual(t, "w", result)
 
 	// Now flush the first 4 runes from the buffer (dropping "Hell" from it)
 	r.Flush(4)
@@ -135,11 +133,11 @@ func TestBuffer_Flush(t *testing.T) {
 	// Rune 0 is now pointing at what originally was rune offset 4.
 	// We can continue reading from there.
 	result = fmt.Sprintf("%c%c%c%c%c%c", at(0), at(1), at(2), at(3), at(4), at(5))
-	AssertEqual(t, "o, wor", result)
+	assertEqual(t, "o, wor", result)
 }
 
 func ExampleBuffer_Flush() {
-	r := read.New(strings.NewReader("dog eat dog!"))
+	r := New(strings.NewReader("dog eat dog!"))
 	at := func(offset int) rune { c, _ := r.RuneAt(offset); return c }
 
 	// Read from the first 4 runes of the input.
@@ -162,33 +160,33 @@ func ExampleBuffer_Flush() {
 }
 
 func TestGivenNumberOfRunesTooHigh_Flush_Panics(t *testing.T) {
-	r := read.New(strings.NewReader("Hello, world!"))
+	r := New(strings.NewReader("Hello, world!"))
 
 	// Fill buffer with "Hello, worl", the first 11 runes.
 	r.RuneAt(10)
 
 	// However, we flush 12 runes, which exceeds the buffer size.
-	AssertPanic(t,
+	assertPanic(t,
 		func() { r.Flush(12) },
 		"parsekit.read.Buffer.Flush(): number of runes to flush "+
 			"(12) exceeds size of the buffer (11)")
 }
 
 func TestGivenEOFFollowedByFlush_EOFCanStillBeRead(t *testing.T) {
-	r := read.New(strings.NewReader("Hello, world!"))
+	r := New(strings.NewReader("Hello, world!"))
 	_, err := r.RuneAt(13)
-	AssertEqual(t, err.Error(), "EOF")
+	assertEqual(t, err.Error(), "EOF")
 	_, err = r.RuneAt(13)
-	AssertEqual(t, err.Error(), "EOF")
+	assertEqual(t, err.Error(), "EOF")
 	_, err = r.RuneAt(14)
-	AssertEqual(t, err.Error(), "EOF")
+	assertEqual(t, err.Error(), "EOF")
 	r.Flush(13)
 	_, err = r.RuneAt(0)
-	AssertEqual(t, err.Error(), "EOF")
+	assertEqual(t, err.Error(), "EOF")
 	_, err = r.RuneAt(1)
-	AssertEqual(t, err.Error(), "EOF")
+	assertEqual(t, err.Error(), "EOF")
 	_, err = r.RuneAt(2)
-	AssertEqual(t, err.Error(), "EOF")
+	assertEqual(t, err.Error(), "EOF")
 }
 
 // In this test, I want to make sure that once a Buffer returns an error,
@@ -202,79 +200,156 @@ func TestGivenErrorFromBuffer_ErrorIsCached(t *testing.T) {
 			io.ErrUnexpectedEOF, // This error must never popup in the tests below.
 		},
 	}
-	r := read.New(input)
+	r := New(input)
 
 	// Read the last availble rune.
 	readRune, _ := r.RuneAt(3)
-	AssertEqual(t, 'd', readRune)
+	assertEqual(t, 'd', readRune)
 
 	// Reading the next offset must result in the io.EOF error from the stub.
 	readRune, err := r.RuneAt(4)
-	AssertEqual(t, utf8.RuneError, readRune)
+	assertEqual(t, utf8.RuneError, readRune)
-	AssertEqual(t, io.EOF, err)
+	assertEqual(t, io.EOF, err)
 
 	// Reading even further should yield the same io.EOF error.
 	readRune, err = r.RuneAt(5)
-	AssertEqual(t, utf8.RuneError, readRune)
+	assertEqual(t, utf8.RuneError, readRune)
-	AssertEqual(t, io.EOF, err)
+	assertEqual(t, io.EOF, err)
 
 	// After an error, we must still be able to read the last rune.
 	readRune, _ = r.RuneAt(3)
-	AssertEqual(t, 'd', readRune)
+	assertEqual(t, 'd', readRune)
 
 	// Flushing updates the error index too.
 	r.Flush(3)
 
 	// The last rune is now at offset 0.
 	readRune, _ = r.RuneAt(0)
-	AssertEqual(t, 'd', readRune)
+	assertEqual(t, 'd', readRune)
 
 	// The io.EOF is now at offset 1.
 	_, err = r.RuneAt(1)
-	AssertEqual(t, io.EOF, err)
+	assertEqual(t, io.EOF, err)
 
 	// Let's flush that last rune too.
 	r.Flush(1)
 
 	// The io.EOF is now at offset 0.
 	_, err = r.RuneAt(0)
-	AssertEqual(t, io.EOF, err)
+	assertEqual(t, io.EOF, err)
 
 	// And reading beyond that offset also yields io.EOF.
 	_, err = r.RuneAt(1)
-	AssertEqual(t, io.EOF, err)
+	assertEqual(t, io.EOF, err)
 }
 
 func TestInputLargerThanDefaultBufSize64(t *testing.T) {
 	input, size := makeLargeStubReader()
-	r := read.New(input)
+	r := New(input)
 
 	readRune, err := r.RuneAt(0)
-	AssertEqual(t, 'X', readRune)
+	assertEqual(t, 'X', readRune)
 	readRune, err = r.RuneAt(size - 1)
-	AssertEqual(t, 'Y', readRune)
+	assertEqual(t, 'Y', readRune)
 	readRune, err = r.RuneAt(size)
-	AssertEqual(t, io.EOF, err)
+	assertEqual(t, io.EOF, err)
 	readRune, err = r.RuneAt(10)
-	AssertEqual(t, 'X', readRune)
+	assertEqual(t, 'X', readRune)
 }
 
 func TestInputLargerThanDefaultBufSize64_WithFirstReadLargerThanBufSize64(t *testing.T) {
 	input, size := makeLargeStubReader()
-	r := read.New(input)
+	r := New(input)
 
 	readRune, _ := r.RuneAt(size - 200)
-	AssertEqual(t, 'X', readRune)
+	assertEqual(t, 'X', readRune)
 	readRune, _ = r.RuneAt(size - 1)
-	AssertEqual(t, 'Y', readRune)
+	assertEqual(t, 'Y', readRune)
 }
 
 func TestInputLargerThanDefaultBufSize64_WithFirstReadToLastByte(t *testing.T) {
 	input, size := makeLargeStubReader()
-	r := read.New(input)
+	r := New(input)
 
 	readRune, _ := r.RuneAt(size - 1)
-	AssertEqual(t, 'Y', readRune)
+	assertEqual(t, 'Y', readRune)
+}
+
+func TestAllocationPatterns(t *testing.T) {
+	input, _ := makeLargeStubReader()
+	r := New(input)
+
+	// The first read will create the standard cache.
+	// store  |x   64     |
+	// buffer |x   64     |
+	assertCache(t, "read 1", r, func() { r.RuneAt(0) }, 0, 64, 1, 64)
+
+	// The first 64 reads will fit in the standard cache.
+	// store  |xxxx64xxxxx|
+	// buffer |xxxx64xxxxx|
+	assertCache(t, "read fill cache", r, func() { r.RuneAt(63) }, 0, 64, 64, 64)
+
+	// Flushing zero input keeps everything as-is.
+	// store  |xxxx64xxxxx|
+	// buffer |xxxx64xxxxx|
+	assertCache(t, "flush zero", r, func() { r.Flush(0) }, 0, 64, 64, 64)
+
+	// Flushing all cached input truncates the cache.
+	// store  |     64    |
+	// buffer |     64    |
+	assertCache(t, "flush full cache", r, func() { r.Flush(64) }, 0, 64, 0, 64)
+
+	// Reading 65 chars will allocate a new store of 2 * size + n.
+	// store  |xxxxx65xxxxx     128        |
+	// buffer |xxxxx65xxxxx     128        |
+	assertCache(t, "read cap + 1", r, func() { r.RuneAt(64) }, 0, 65+128, 65, 65+128)
+
+	// A partial flush frees the start of the store and moves
+	// the buffer slice.
+	// store  |   50   x15x     128        |
+	// buffer         |x15x     128        |
+	assertCache(t, "flush partial", r, func() { r.Flush(50) }, 0, 50+15+128, 15, 15+128)
+
+	// The capacity for the buffer is now 2*64 + 15
+	// This number of runes can be read, filling up the store
+	// without a new allocation.
+	// store  |   50   xxxxxxxxx143xxxxxxxx|
+	// buffer         |xxxxxxxxx143xxxxxxxx|
+	assertCache(t, "read fill cache after partial flush", r, func() { r.RuneAt(142) }, 0, 50+143, 143, 143)
+
+	// Flush the full input.
+	// store  |            193             |
+	// buffer |                            |
+	assertCache(t, "flush full cache after partial flush", r, func() { r.Flush(143) }, 0, 193, 0, 193)
+
+	// Read a bit more than half the capacity.
+	// store  |xxxxxx101xxxxxxxx    92     |
+	// buffer |xxxxxx101xxxxxxxx    92     |
+	assertCache(t, "read more than half the cap", r, func() { r.RuneAt(100) }, 0, 193, 101, 193)
+
+	// Then flush almost all input.
+	// store  |      100     x1x    92     |
+	// buffer               |x1x    92     |
+	assertCache(t, "flush almost all input", r, func() { r.Flush(100) }, 0, 193, 1, 93)
+
+	// Again read a bit more than half the capacity. This does not fit at the
+	// end of the store, but by moving the current buffer to the start of the
+	// store (where it fits), space is freed up for the read operation.
+	// store  |xxxxx100xxxxxx      93      |
+	// buffer |xxxxx100xxxxxx      93      |
+	assertCache(t, "read beyond cap with free space at start of store", r, func() { r.RuneAt(99) }, 0, 193, 100, 193)
+
+	// Now flush only one rune from the cache.
+	// store  |1 xxxx99xxxxx      93      |
+	// buffer   |xxxx99xxxxx      93      |
+	assertCache(t, "flush 1", r, func() { r.Flush(1) }, 0, 193, 99, 192)
+
+	// Now read one more than the capacity. This will not fit, so space has
+	// to be made. Since there's 1 free space at the start of the store,
+	// the data is moved to the start and no reallocation is needed.
+	// store  |1 xxxx99xxxxx      93      |
+	// buffer   |xxxx99xxxxx      93      |
+	assertCache(t, "read 1 more than cap with 1 free at start", r, func() { r.RuneAt(192) }, 0, 193, 193, 193)
 }
 
 func makeLargeStubReader() (*StubReader, int) {

tokenize/api.go

@@ -201,7 +201,7 @@ func (i *API) Dispose() {
 func (i *API) clearResults() {
 	i.result.lastRune = nil
 	i.result.runes = []rune{}
-	i.result.tokens = []*Token{}
+	i.result.tokens = []Token{}
 	i.result.err = nil
 }
 

tokenize/api_test.go

@@ -55,11 +55,11 @@ func ExampleAPI_Result() {
 	fmt.Printf("API result runes: %q\n", api.Result().Runes())
 	fmt.Printf("API third rune: %q\n", api.Result().Rune(2))
 
-	result.AddTokens(&tokenize.Token{
+	result.AddTokens(tokenize.Token{
 		Runes: []rune("demo 1"),
 		Type:  42,
 		Value: "towel"})
-	result.AddTokens(&tokenize.Token{
+	result.AddTokens(tokenize.Token{
 		Runes: []rune("demo 2"),
 		Type:  73,
 		Value: "Zaphod"})

tokenize/handlers_builtin.go

@@ -712,11 +712,11 @@ func MatchEndOfFile() Handler {
 	}
 }
 
-// MatchUntilEndOfLine creates a Handler function that accepts any rune
+// MatchUntilEndOfLine creates a Handler function that accepts one or
-// until the end of the line (or file when that's the case).
+// more runes until the end of the line (or file when that's the case).
 // The newline itself is not included in the match.
 func MatchUntilEndOfLine() Handler {
-	return MatchZeroOrMore(MatchNot(MatchEndOfLine()))
+	return MatchOneOrMore(MatchNot(MatchEndOfLine()))
 }
 
 // MatchAnyRune creates a Handler function that checks if a rune can be
@@ -1437,7 +1437,7 @@ func MakeTokenByCallback(toktype interface{}, handler Handler, makeValue func(t
 			// e.g. when a parsing hierarchy looks like ("date" ("year", "month" "day")), the
 			// tokens will end up in the order "date", "year", "month", "day". When we'd add the
 			// token to the child here, the order would have been "year", "month", "day", "date".
-			token := &Token{Type: toktype, Runes: child.Result().Runes(), Value: makeValue(child)}
+			token := Token{Type: toktype, Runes: child.Result().Runes(), Value: makeValue(child)}
 			t.Result().AddTokens(token)
 			child.Merge()
 
@@ -1454,7 +1454,7 @@ func MakeTokenGroup(toktype interface{}, handler Handler) Handler {
 		child := t.Fork()
 		if handler(child) {
 			result := child.Result()
-			token := &Token{Type: toktype, Runes: result.Runes(), Value: result.Tokens()}
+			token := Token{Type: toktype, Runes: result.Runes(), Value: result.Tokens()}
 			result.SetTokens(token)
 			child.Merge()
 			return true

tokenize/result.go

@@ -10,7 +10,7 @@ import (
 type Result struct {
 	lastRune *runeInfo // Information about the last rune read using NextRune()
 	runes    []rune    // runes as added to the result by tokenize.Handler functions
-	tokens   []*Token  // Tokens as added to the result by tokenize.Handler functions
+	tokens   []Token   // Tokens as added to the result by tokenize.Handler functions
 	cursor   *Cursor   // current read cursor position, relative to the start of the file
 	offset   int       // current rune offset relative to the Reader's sliding window
 	err      error     // can be used by a Handler to report a specific issue with the input
@@ -69,7 +69,7 @@ func (t Token) String() string {
 func newResult() *Result {
 	return &Result{
 		runes:  []rune{},
-		tokens: []*Token{},
+		tokens: []Token{},
 		cursor: &Cursor{},
 	}
 }
@@ -122,29 +122,26 @@ func (r *Result) String() string {
 
 // ClearTokens clears the tokens in the Result.
 func (r *Result) ClearTokens() {
-	r.tokens = []*Token{}
+	r.tokens = []Token{}
 }
 
 // SetTokens replaces the Tokens from the Result with the provided tokens.
-func (r *Result) SetTokens(tokens ...*Token) {
+func (r *Result) SetTokens(tokens ...Token) {
-	r.ClearTokens()
+	r.tokens = tokens
-	for _, t := range tokens {
-		r.AddTokens(t)
-	}
 }
 
 // AddTokens is used to add Tokens to the Result.
-func (r *Result) AddTokens(tokens ...*Token) {
+func (r *Result) AddTokens(tokens ...Token) {
 	r.tokens = append(r.tokens, tokens...)
 }
 
 // Tokens retrieves the Tokens from the Result.
-func (r *Result) Tokens() []*Token {
+func (r *Result) Tokens() []Token {
 	return r.tokens
 }
 
 // Token retrieves a single Token from the Result at the specified index.
-func (r *Result) Token(idx int) *Token {
+func (r *Result) Token(idx int) Token {
 	return r.tokens[idx]
 }