blob: 0af8ae304978b44bcc563c46069726c932b5bb54 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
|
#ifndef _QueryParser_h_
#define _QueryParser_h_
//
// QueryParser.h
//
// QueryParser: (abstract) root of the family of classes that create
// Query trees by analyzing query strings.
// The main public interface consists on Parse(),
// which does the job.
// The subclasses must provide a lexer.
// This class implements also the common behaviour needed to
// parse single words and phrases.
//
// Part of the ht://Dig package <http://www.htdig.org/>
// Copyright (c) 1995-2004 The ht://Dig Group
// For copyright details, see the file COPYING in your distribution
// or the GNU Library General Public License (LGPL) version 2 or later
// <http://www.gnu.org/copyleft/lgpl.html>
//
// $Id: QueryParser.h,v 1.4 2004/05/28 13:15:24 lha Exp $
//
#include "QueryLexer.h"
class Query;
class FuzzyExpander;
// abstract
class QueryParser
{
public:
virtual ~QueryParser() {}
// do it
Query *Parse(const String &query_string);
// contains a diagnostic if Parse() failed
const String &Error() const
{ return error; }
// set a fuzzy word expansion policy
static void SetFuzzyExpander(FuzzyExpander *x)
{ expander = x; }
protected:
QueryParser() {}
// apply a syntax -- tbd by derived classes
virtual Query *ParseExpression() = 0;
// access to the lexer -- provided by children
virtual QueryLexer &Token() = 0;
// parse one (fuzzy) word
Query *ParseWord();
// parse an exact word
Query *ParseExactWord();
// parse a phrase
Query *ParsePhrase();
// set the error string on syntax error
void Expected(const String &what);
// the current fuzzy expansion policy if some
static FuzzyExpander *expander;
private:
// syntax error if some
String error;
};
#endif
|
