parser.go

Documentation: github.com/magiconair/properties

     1  // Copyright 2013-2022 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  
     5  package properties
     6  
     7  import (
     8  	"fmt"
     9  	"runtime"
    10  )
    11  
    12  type parser struct {
    13  	lex *lexer
    14  }
    15  
    16  func 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  
    53  done:
    54  	return properties, nil
    55  }
    56  
    57  func (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  
    62  func (p *parser) expectOneOf(expected ...itemType) (token item) {
    63  	token = p.lex.nextItem()
    64  	for _, v := range expected {
    65  		if token.typ == v {
    66  			return token
    67  		}
    68  	}
    69  	p.unexpected(token)
    70  	panic("unexpected token")
    71  }
    72  
    73  func (p *parser) unexpected(token item) {
    74  	p.errorf(token.String())
    75  }
    76  
    77  // recover is the handler that turns panics into returns from the top level of Parse.
    78  func (p *parser) recover(errp *error) {
    79  	e := recover()
    80  	if e != nil {
    81  		if _, ok := e.(runtime.Error); ok {
    82  			panic(e)
    83  		}
    84  		*errp = e.(error)
    85  	}
    86  }
    87
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