1// Copyright 2015 The Go Authors. All rights reserved.2// Use of this source code is governed by a BSD-style3// license that can be found in the LICENSE file.45package lex67import (8	"text/scanner"910	"cmd/internal/src"11)1213// A Slice reads from a slice of Tokens.14type Slice struct {15	tokens []Token16	base   *src.PosBase17	line   int18	pos    int19}2021func NewSlice(base *src.PosBase, line int, tokens []Token) *Slice {22	return &Slice{23		tokens: tokens,24		base:   base,25		line:   line,26		pos:    -1, // Next will advance to zero.27	}28}2930func (s *Slice) Next() ScanToken {31	s.pos++32	if s.pos >= len(s.tokens) {33		return scanner.EOF34	}35	return s.tokens[s.pos].ScanToken36}3738func (s *Slice) Text() string {39	return s.tokens[s.pos].text40}4142func (s *Slice) File() string {43	return s.base.Filename()44}4546func (s *Slice) Base() *src.PosBase {47	return s.base48}4950func (s *Slice) SetBase(base *src.PosBase) {51	// Cannot happen because we only have slices of already-scanned text,52	// but be prepared.53	s.base = base54}5556func (s *Slice) Line() int {57	return s.line58}5960func (s *Slice) Col() int {61	// TODO: Col is only called when defining a macro and all it cares about is increasing62	// position to discover whether there is a blank before the parenthesis.63	// We only get here if defining a macro inside a macro.64	// This imperfect implementation means we cannot tell the difference between65	//	#define A #define B(x) x66	// and67	//	#define A #define B (x) x68	// The first definition of B has an argument, the second doesn't. Because we let69	// text/scanner strip the blanks for us, this is extremely rare, hard to fix, and not worth it.70	return s.pos71}7273func (s *Slice) Close() {74}