1// Copyright 2018 Frank Schroeder. 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 5package properties 6 7import ( 8 "fmt" 9 "runtime" 10) 11 12type parser struct { 13 lex *lexer 14} 15 16func parse(input string) (properties *Properties, err error) { 17 p := &parser{lex: lex(input)} 18 defer p.recover(&err) 19 20 properties = NewProperties() 21 key := "" 22 comments := []string{} 23 24 for { 25 token := p.expectOneOf(itemComment, itemKey, itemEOF) 26 switch token.typ { 27 case itemEOF: 28 goto done 29 case itemComment: 30 comments = append(comments, token.val) 31 continue 32 case itemKey: 33 key = token.val 34 if _, ok := properties.m[key]; !ok { 35 properties.k = append(properties.k, key) 36 } 37 } 38 39 token = p.expectOneOf(itemValue, itemEOF) 40 if len(comments) > 0 { 41 properties.c[key] = comments 42 comments = []string{} 43 } 44 switch token.typ { 45 case itemEOF: 46 properties.m[key] = "" 47 goto done 48 case itemValue: 49 properties.m[key] = token.val 50 } 51 } 52 53done: 54 return properties, nil 55} 56 57func (p *parser) errorf(format string, args ...interface{}) { 58 format = fmt.Sprintf("properties: Line %d: %s", p.lex.lineNumber(), format) 59 panic(fmt.Errorf(format, args...)) 60} 61 62func (p *parser) expect(expected itemType) (token item) { 63 token = p.lex.nextItem() 64 if token.typ != expected { 65 p.unexpected(token) 66 } 67 return token 68} 69 70func (p *parser) expectOneOf(expected ...itemType) (token item) { 71 token = p.lex.nextItem() 72 for _, v := range expected { 73 if token.typ == v { 74 return token 75 } 76 } 77 p.unexpected(token) 78 panic("unexpected token") 79} 80 81func (p *parser) unexpected(token item) { 82 p.errorf(token.String()) 83} 84 85// recover is the handler that turns panics into returns from the top level of Parse. 86func (p *parser) recover(errp *error) { 87 e := recover() 88 if e != nil { 89 if _, ok := e.(runtime.Error); ok { 90 panic(e) 91 } 92 *errp = e.(error) 93 } 94 return 95} 96