php-parser/lexer.go

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package main
import (
"bufio"
"go/token"
"io"
"github.com/cznic/golex/lex"
)
// Allocate Character classes anywhere in [0x80, 0xFF].
const (
classUnicodeLeter = iota + 0x80
classUnicodeDigit
classOther
)
type lexer struct {
*lex.Lexer
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stateStack []int
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}
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func newLexer(src io.Reader, fName string) *lexer {
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file := token.NewFileSet().AddFile(fName, -1, 1<<31-1)
lx, err := lex.New(file, bufio.NewReader(src), lex.RuneClass(rune2Class))
if err != nil {
panic(err)
}
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return &lexer{lx, []int{0}}
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}
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func (l *lexer) ungetN(n int) []byte {
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l.Unget(l.Lookahead())
chars := l.Token()
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for i := 1; i <= n; i++ {
char := chars[len(chars)-i]
l.Unget(char)
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}
buf := l.TokenBytes(nil)
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buf = buf[:len(buf)-n]
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return buf
}
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func (l *lexer) pushState(state int) {
l.stateStack = append(l.stateStack, state)
}
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func (l *lexer) popState() {
len := len(l.stateStack)
if len <= 1 {
return
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}
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l.stateStack = l.stateStack[:len-1]
}
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func (l *lexer) begin(state int) {
len := len(l.stateStack)
l.stateStack = l.stateStack[:len-1]
l.stateStack = append(l.stateStack, state)
}
func (l *lexer) getCurrentState() int {
return l.stateStack[len(l.stateStack)-1]
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}