1 // Copyright 2015 The Go Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style 3 // license that can be found in the LICENSE file. 4 5 package lex 6 7 import "text/scanner" 8 9 // A Slice reads from a slice of Tokens. 10 type Slice struct { 11 tokens []Token 12 fileName string 13 line int 14 pos int 15 } 16 17 func NewSlice(fileName string, line int, tokens []Token) *Slice { 18 return &Slice{ 19 tokens: tokens, 20 fileName: fileName, 21 line: line, 22 pos: -1, // Next will advance to zero. 23 } 24 } 25 26 func (s *Slice) Next() ScanToken { 27 s.pos++ 28 if s.pos >= len(s.tokens) { 29 return scanner.EOF 30 } 31 return s.tokens[s.pos].ScanToken 32 } 33 34 func (s *Slice) Text() string { 35 return s.tokens[s.pos].text 36 } 37 38 func (s *Slice) File() string { 39 return s.fileName 40 } 41 42 func (s *Slice) Line() int { 43 return s.line 44 } 45 46 func (s *Slice) Col() int { 47 // Col is only called when defining a macro, which can't reach here. 48 panic("cannot happen: slice col") 49 } 50 51 func (s *Slice) SetPos(line int, file string) { 52 // Cannot happen because we only have slices of already-scanned 53 // text, but be prepared. 54 s.line = line 55 s.fileName = file 56 } 57 58 func (s *Slice) Close() { 59 } 60
