mirror of https://github.com/golang/go.git
57 lines
1.3 KiB
Go
57 lines
1.3 KiB
Go
// Copyright 2015 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package lex
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import "text/scanner"
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// A Stack is a stack of TokenReaders. As the top TokenReader hits EOF,
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// it resumes reading the next one down.
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type Stack struct {
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tr []TokenReader
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}
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// Push adds tr to the top (end) of the input stack. (Popping happens automatically.)
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func (s *Stack) Push(tr TokenReader) {
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s.tr = append(s.tr, tr)
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}
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func (s *Stack) Next() ScanToken {
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tos := s.tr[len(s.tr)-1]
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tok := tos.Next()
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for tok == scanner.EOF && len(s.tr) > 1 {
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tos.Close()
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/*
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// If it's not a macro (a Slice at this point), pop the line history stack and close the file descriptor.
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if _, isMacro := tos.(*Slice); !isMacro {
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// TODO: close file descriptor.
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obj.Linklinehist(linkCtxt, histLine, "<pop>", 0)
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}
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*/
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// Pop the topmost item from the stack and resume with the next one down.
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s.tr = s.tr[:len(s.tr)-1]
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tok = s.Next()
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}
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return tok
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}
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func (s *Stack) Text() string {
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return s.tr[len(s.tr)-1].Text()
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}
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func (s *Stack) File() string {
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return s.tr[len(s.tr)-1].File()
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}
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func (s *Stack) Line() int {
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return s.tr[len(s.tr)-1].Line()
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}
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func (s *Stack) SetPos(line int, file string) {
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s.tr[len(s.tr)-1].SetPos(line, file)
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}
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func (s *Stack) Close() { // Unused.
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}
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