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Diffstat (limited to 'gcc-4.8.1/libgo/go/exp/ebnf/parser.go')
-rw-r--r--gcc-4.8.1/libgo/go/exp/ebnf/parser.go190
1 files changed, 0 insertions, 190 deletions
diff --git a/gcc-4.8.1/libgo/go/exp/ebnf/parser.go b/gcc-4.8.1/libgo/go/exp/ebnf/parser.go
deleted file mode 100644
index 7a7e3cc16..000000000
--- a/gcc-4.8.1/libgo/go/exp/ebnf/parser.go
+++ /dev/null
@@ -1,190 +0,0 @@
-// Copyright 2009 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package ebnf
-
-import (
- "io"
- "strconv"
- "text/scanner"
-)
-
-type parser struct {
- errors errorList
- scanner scanner.Scanner
- pos scanner.Position // token position
- tok rune // one token look-ahead
- lit string // token literal
-}
-
-func (p *parser) next() {
- p.tok = p.scanner.Scan()
- p.pos = p.scanner.Position
- p.lit = p.scanner.TokenText()
-}
-
-func (p *parser) error(pos scanner.Position, msg string) {
- p.errors = append(p.errors, newError(pos, msg))
-}
-
-func (p *parser) errorExpected(pos scanner.Position, msg string) {
- msg = `expected "` + msg + `"`
- if pos.Offset == p.pos.Offset {
- // the error happened at the current position;
- // make the error message more specific
- msg += ", found " + scanner.TokenString(p.tok)
- if p.tok < 0 {
- msg += " " + p.lit
- }
- }
- p.error(pos, msg)
-}
-
-func (p *parser) expect(tok rune) scanner.Position {
- pos := p.pos
- if p.tok != tok {
- p.errorExpected(pos, scanner.TokenString(tok))
- }
- p.next() // make progress in any case
- return pos
-}
-
-func (p *parser) parseIdentifier() *Name {
- pos := p.pos
- name := p.lit
- p.expect(scanner.Ident)
- return &Name{pos, name}
-}
-
-func (p *parser) parseToken() *Token {
- pos := p.pos
- value := ""
- if p.tok == scanner.String {
- value, _ = strconv.Unquote(p.lit)
- // Unquote may fail with an error, but only if the scanner found
- // an illegal string in the first place. In this case the error
- // has already been reported.
- p.next()
- } else {
- p.expect(scanner.String)
- }
- return &Token{pos, value}
-}
-
-// ParseTerm returns nil if no term was found.
-func (p *parser) parseTerm() (x Expression) {
- pos := p.pos
-
- switch p.tok {
- case scanner.Ident:
- x = p.parseIdentifier()
-
- case scanner.String:
- tok := p.parseToken()
- x = tok
- const ellipsis = '…' // U+2026, the horizontal ellipsis character
- if p.tok == ellipsis {
- p.next()
- x = &Range{tok, p.parseToken()}
- }
-
- case '(':
- p.next()
- x = &Group{pos, p.parseExpression()}
- p.expect(')')
-
- case '[':
- p.next()
- x = &Option{pos, p.parseExpression()}
- p.expect(']')
-
- case '{':
- p.next()
- x = &Repetition{pos, p.parseExpression()}
- p.expect('}')
- }
-
- return x
-}
-
-func (p *parser) parseSequence() Expression {
- var list Sequence
-
- for x := p.parseTerm(); x != nil; x = p.parseTerm() {
- list = append(list, x)
- }
-
- // no need for a sequence if list.Len() < 2
- switch len(list) {
- case 0:
- p.errorExpected(p.pos, "term")
- return &Bad{p.pos, "term expected"}
- case 1:
- return list[0]
- }
-
- return list
-}
-
-func (p *parser) parseExpression() Expression {
- var list Alternative
-
- for {
- list = append(list, p.parseSequence())
- if p.tok != '|' {
- break
- }
- p.next()
- }
- // len(list) > 0
-
- // no need for an Alternative node if list.Len() < 2
- if len(list) == 1 {
- return list[0]
- }
-
- return list
-}
-
-func (p *parser) parseProduction() *Production {
- name := p.parseIdentifier()
- p.expect('=')
- var expr Expression
- if p.tok != '.' {
- expr = p.parseExpression()
- }
- p.expect('.')
- return &Production{name, expr}
-}
-
-func (p *parser) parse(filename string, src io.Reader) Grammar {
- p.scanner.Init(src)
- p.scanner.Filename = filename
- p.next() // initializes pos, tok, lit
-
- grammar := make(Grammar)
- for p.tok != scanner.EOF {
- prod := p.parseProduction()
- name := prod.Name.String
- if _, found := grammar[name]; !found {
- grammar[name] = prod
- } else {
- p.error(prod.Pos(), name+" declared already")
- }
- }
-
- return grammar
-}
-
-// Parse parses a set of EBNF productions from source src.
-// It returns a set of productions. Errors are reported
-// for incorrect syntax and if a production is declared
-// more than once; the filename is used only for error
-// positions.
-//
-func Parse(filename string, src io.Reader) (Grammar, error) {
- var p parser
- grammar := p.parse(filename, src)
- return grammar, p.errors.Err()
-}