Squishing out more performance.

tokenize/api.go

@@ -134,6 +134,13 @@ func (i *API) NextRune() (rune, error) {
 	return readRune, err
 }
 
+// PeekRune returns the rune at the provided offset.
+//
+// The read cursor and current read offset are not updated by this operation.
+func (i *API) PeekRune(offset int) (rune, error) {
+	return i.reader.RuneAt(i.stackFrame.offset + offset)
+}
+
 // Accept the last rune as read by NextRune() into the Result runes and move
 // the cursor forward.
 //
@@ -148,7 +155,12 @@ func (i *API) Accept() {
 			"but the prior call to NextRune() failed")
 	}
 
-	newRuneEnd := i.stackFrame.runeEnd + 1
+	i.accept(i.lastRune)
+}
+
+func (i *API) accept(runes ...rune) {
+	curRuneEnd := i.stackFrame.runeEnd
+	newRuneEnd := curRuneEnd + len(runes)
 
 	// Grow the runes capacity when needed.
 	if cap(i.runes) < newRuneEnd {
@@ -159,10 +171,12 @@ func (i *API) Accept() {
 		i.runes = i.runes[0:newRuneEnd]
 	}
 
-	i.runes[newRuneEnd-1] = i.lastRune
-	i.stackFrame.runeEnd++
-	i.stackFrame.cursor.moveByRune(i.lastRune)
-	i.stackFrame.offset++
+	for offset, r := range runes {
+		i.runes[curRuneEnd+offset] = r
+		i.stackFrame.cursor.moveByRune(r)
+	}
+	i.stackFrame.runeEnd = newRuneEnd
+	i.stackFrame.offset += len(runes)
 	i.runeRead = false
 }
 

tokenize/api_test.go

@@ -26,6 +26,20 @@ func ExampleAPI_NextRune() {
 	// API results: ""
 }
 
+func ExampleAPI_PeekRune() {
+	api := tokenize.NewAPI("The input that the API will handle")
+
+	r1, err := api.PeekRune(19) // 'A'
+	r2, err := api.PeekRune(20) // 'P'
+	r3, err := api.PeekRune(21) // 'I'
+	_, err = api.PeekRune(100)  // EOF
+
+	fmt.Printf("%c%c%c %s\n", r1, r2, r3, err)
+
+	// Output:
+	// API EOF
+}
+
 func ExampleAPI_Accept() {
 	api := tokenize.NewAPI("The input that the API will handle")
 	api.NextRune() // reads 'T'

tokenize/handlers_builtin.go

@@ -335,14 +335,32 @@ var T = struct {
 
 // MatchRune creates a Handler function that matches against the provided rune.
 func MatchRune(expected rune) Handler {
-	return MatchRuneByCallback(func(r rune) bool { return r == expected })
+	return func(t *API) bool {
+		r, err := t.PeekRune(0)
+		if err == nil && r == expected {
+			t.accept(r)
+			return true
+		}
+		return false
+	}
 }
 
 // MatchRunes creates a Handler function that checks if the input matches
 // 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) })
+	return func(t *API) bool {
+		r, err := t.PeekRune(0)
+		if err != nil {
+			return false
+		}
+		for _, e := range expected {
+			if r == e {
+				t.accept(r)
+				return true
+			}
+		}
+		return false
+	}
 }
 
 // MatchRuneRange creates a Handler function that checks if the input
@@ -356,13 +374,37 @@ func MatchRuneRange(start rune, end rune) Handler {
 	if end < start {
 		callerPanic("MatchRuneRange", "Handler: {name} definition error at {caller}: start %q must not be < end %q", start, end)
 	}
-	return MatchRuneByCallback(func(r rune) bool { return r >= start && r <= end })
+	return func(t *API) bool {
+		r, err := t.PeekRune(0)
+		if err == nil && r >= start && r <= end {
+			t.accept(r)
+			return true
+		}
+		return false
+	}
 }
 
 // MatchNewline creates a handler that matches a newline, which is either
 // a DOS-style newline (CRLF, \r\n) or a UNIX-style newline (just a LF, \n).
 func MatchNewline() Handler {
-	return MatchAny(MatchStr("\r\n"), MatchRune('\n'))
+	return func(t *API) bool {
+		r1, err := t.PeekRune(0)
+		if err != nil {
+			return false
+		}
+		if r1 == '\n' {
+			t.accept(r1)
+			return true
+		}
+		if r1 == '\r' {
+			r2, err := t.PeekRune(1)
+			if err == nil && r2 == '\n' {
+				t.accept(r1, r2)
+				return true
+			}
+		}
+		return false
+	}
 }
 
 // MatchBlank creates a Handler that matches one rune from the input
@@ -371,7 +413,14 @@ func MatchNewline() Handler {
 // When you need whitespace matching, which also includes characters like
 // newlines, then take a look at MatchWhitespace().
 func MatchBlank() Handler {
-	return MatchRuneByCallback(func(r rune) bool { return r == ' ' || r == '\t' })
+	return func(t *API) bool {
+		r, err := t.NextRune()
+		if err == nil && (r == ' ' || r == '\t') {
+			t.Accept()
+			return true
+		}
+		return false
+	}
 }
 
 // MatchBlanks creates a Handler that matches the input against one
@@ -382,14 +431,63 @@ func MatchBlank() Handler {
 // When you need unicode whitespace matching, which also includes characters
 // like a vertical tab, then make use of MatchUnicodeSpace().
 func MatchBlanks() Handler {
-	return MatchOneOrMore(MatchBlank())
+	return func(t *API) bool {
+		// Match the first blank.
+		r, err := t.PeekRune(0)
+		if err != nil || (r != ' ' && r != '\t') {
+			return false
+		}
+
+		// Now match any number of followup blanks. We've already got
+		// a successful match at this point, so we'll always return true at the end.
+		for {
+			r, err := t.PeekRune(0)
+			if err != nil || (r != ' ' && r != '\t') {
+				return true
+			}
+			t.accept(r)
+		}
+	}
 }
 
 // MatchWhitespace creates a Handler that matches the input against one or more
 // whitespace characters, defined as space ' ', tab, ' ', newline '\n' (LF) and
 // carriage return '\r' followed by a newline '\n' (CRLF).
 func MatchWhitespace() Handler {
-	return MatchOneOrMore(MatchBlank().Or(MatchNewline()))
+	return func(t *API) bool {
+		// Match the first whitespace.
+		r1, err := t.PeekRune(0)
+		if err != nil || (r1 != ' ' && r1 != '\t' && r1 != '\n' && r1 != '\r') {
+			return false
+		}
+		if r1 == '\r' {
+			r2, err := t.PeekRune(1)
+			if err != nil || r2 != '\n' {
+				return false
+			}
+			t.accept(r1, r2)
+		} else {
+			t.accept(r1)
+		}
+
+		// Now match any number of followup whitespace. We've already got
+		// a successful match at this point, so we'll always return true at the end.
+		for {
+			r1, err := t.PeekRune(0)
+			if err != nil || (r1 != ' ' && r1 != '\t' && r1 != '\n' && r1 != '\r') {
+				return true
+			}
+			if r1 == '\r' {
+				r2, err := t.PeekRune(1)
+				if err != nil || r2 != '\n' {
+					return true
+				}
+				t.accept(r1, r2)
+			} else {
+				t.accept(r1)
+			}
+		}
+	}
 }
 
 // MatchUnicodeSpace creates a Handler that matches the input against one or more
@@ -406,9 +504,9 @@ func MatchUnicodeSpace() Handler {
 // so those can be used. E.g. MatchRuneByCallback(unicode.IsLower).
 func MatchRuneByCallback(callback func(rune) bool) Handler {
 	return func(t *API) bool {
-		r, err := t.NextRune()
+		r, err := t.PeekRune(0)
 		if err == nil && callback(r) {
-			t.Accept()
+			t.accept(r)
 			return true
 		}
 		return false
@@ -417,28 +515,56 @@ func MatchRuneByCallback(callback func(rune) bool) Handler {
 
 // MatchEndOfLine creates a Handler that matches a newline ("\r\n" or "\n") or EOF.
 func MatchEndOfLine() Handler {
-	return MatchAny(MatchNewline(), MatchEndOfFile())
+	return func(t *API) bool {
+		r1, err := t.PeekRune(0)
+		if err != nil {
+			return err == io.EOF
+		}
+		if r1 == '\n' {
+			t.accept(r1)
+			return true
+		}
+		if r1 == '\r' {
+			r2, _ := t.PeekRune(1)
+			if r2 == '\n' {
+				t.accept(r1, r2)
+				return true
+			}
+		}
+		return false
+	}
 }
 
 // MatchStr creates a Handler that matches the input against the provided string.
 func MatchStr(expected string) Handler {
-	var handlers = make([]Handler, len(expected))
-	for i, r := range expected {
-		handlers[i] = MatchRune(r)
+	return func(t *API) bool {
+		for i, e := range expected {
+			r, err := t.PeekRune(i)
+			if err != nil || e != r {
+				return false
+			}
+		}
+		t.accept([]rune(expected)...)
+		return true
 	}
-	return MatchSeq(handlers...)
 }
 
 // MatchStrNoCase creates a Handler that matches the input against the
 // provided string in a case-insensitive manner.
 func MatchStrNoCase(expected string) Handler {
-	var handlers = []Handler{}
-	for _, r := range expected {
-		u := unicode.ToUpper(r)
-		l := unicode.ToLower(r)
-		handlers = append(handlers, MatchRunes(u, l))
+	l := len([]rune(expected))
+	matches := make([]rune, l)
+	return func(t *API) bool {
+		for i, e := range expected {
+			r, err := t.PeekRune(i)
+			if err != nil || unicode.ToUpper(e) != unicode.ToUpper(r) {
+				return false
+			}
+			matches[i] = r
+		}
+		t.accept(matches...)
+		return true
 	}
-	return MatchSeq(handlers...)
 }
 
 // MatchOptional creates a Handler that makes the provided Handler optional.
@@ -756,9 +882,9 @@ func MatchAnyRune() Handler {
 // UTF8 rune can be read from the input.
 func MatchValidRune() Handler {
 	return func(t *API) bool {
-		r, err := t.NextRune()
+		r, err := t.PeekRune(0)
 		if err == nil && r != utf8.RuneError {
-			t.Accept()
+			t.accept(r)
 			return true
 		}
 		return false
@@ -769,9 +895,9 @@ func MatchValidRune() Handler {
 // UTF8 rune can be read from the input.
 func MatchInvalidRune() Handler {
 	return func(t *API) bool {
-		r, err := t.NextRune()
+		r, err := t.PeekRune(0)
 		if err == nil && r == utf8.RuneError {
-			t.Accept()
+			t.accept(r)
 			return true
 		}
 		return false
@@ -822,9 +948,106 @@ func MatchFloat() Handler {
 //
 // False falues: false, FALSE, False, 0, f, F
 func MatchBoolean() Handler {
-	trues := MatchAny(MatchStr("true"), MatchStr("TRUE"), MatchStr("True"), MatchRune('1'), MatchRune('t'), MatchRune('T'))
-	falses := MatchAny(MatchStr("false"), MatchStr("FALSE"), MatchStr("False"), MatchRune('0'), MatchRune('f'), MatchRune('F'))
-	return MatchAny(trues, falses)
+	return func(t *API) bool {
+		r1, err := t.PeekRune(0)
+		if err != nil {
+			return false
+		}
+		if r1 == '1' || r1 == '0' {
+			t.accept(r1)
+			return true
+		}
+		if r1 == 't' {
+			r2, err := t.PeekRune(1)
+			if err == nil && r2 == 'r' {
+				r3, err := t.PeekRune(2)
+				if err == nil && r3 == 'u' {
+					r4, err := t.PeekRune(3)
+					if err == nil && r4 == 'e' {
+						t.accept(r1, r2, r3, r4)
+						return true
+					}
+				}
+			}
+			t.accept(r1)
+			return true
+		}
+		if r1 == 'T' {
+			r2, err := t.PeekRune(1)
+			if err == nil && r2 == 'r' {
+				r3, err := t.PeekRune(2)
+				if err == nil && r3 == 'u' {
+					r4, err := t.PeekRune(3)
+					if err == nil && r4 == 'e' {
+						t.accept(r1, r2, r3, r4)
+						return true
+					}
+				}
+			}
+			if err == nil && r2 == 'R' {
+				r3, err := t.PeekRune(2)
+				if err == nil && r3 == 'U' {
+					r4, err := t.PeekRune(3)
+					if err == nil && r4 == 'E' {
+						t.accept(r1, r2, r3, r4)
+						return true
+					}
+				}
+			}
+			t.accept(r1)
+			return true
+		}
+		if r1 == 'f' {
+			r2, err := t.PeekRune(1)
+			if err == nil && r2 == 'a' {
+				r3, err := t.PeekRune(2)
+				if err == nil && r3 == 'l' {
+					r4, err := t.PeekRune(3)
+					if err == nil && r4 == 's' {
+						r5, err := t.PeekRune(4)
+						if err == nil && r5 == 'e' {
+							t.accept(r1, r2, r3, r4, r5)
+							return true
+						}
+					}
+				}
+			}
+			t.accept(r1)
+			return true
+		}
+		if r1 == 'F' {
+			r2, err := t.PeekRune(1)
+			if err == nil && r2 == 'a' {
+				r3, err := t.PeekRune(2)
+				if err == nil && r3 == 'l' {
+					r4, err := t.PeekRune(3)
+					if err == nil && r4 == 's' {
+						r5, err := t.PeekRune(4)
+						if err == nil && r5 == 'e' {
+							t.accept(r1, r2, r3, r4, r5)
+							return true
+						}
+					}
+				}
+			}
+			if err == nil && r2 == 'A' {
+				r3, err := t.PeekRune(2)
+				if err == nil && r3 == 'L' {
+					r4, err := t.PeekRune(3)
+					if err == nil && r4 == 'S' {
+						r5, err := t.PeekRune(4)
+						if err == nil && r5 == 'E' {
+							t.accept(r1, r2, r3, r4, r5)
+							return true
+						}
+					}
+				}
+			}
+			t.accept(r1)
+			return true
+		}
+		return false
+	}
 }
 
 // MatchASCII creates a Handler function that matches against any