xapian-bindings/perl/Xapian/QueryParser.pm

   1 package Xapian::QueryParser;
   2
   3 =head1 NAME
   4
   5 Xapian::QueryParser - Parse a query string into a Xapian::Query object
   6
   7 =head1 DESCRIPTION
   8
   9 This module turns a human readable string into something Xapian can
  10 understand.  The syntax supported is designed to be similar to other web
  11 based search engines, so that users familiar with them don't have to learn
  12 a whole new syntax.
  13
  14 =head1 SYNOPSIS
  15
  16   use Xapian qw/:standard/;
  17
  18   my $qp = new Xapian::QueryParser( [$database] );
  19   $qp->set_stemmer(new Xapian::Stem("english"));
  20   $qp->set_default_op(OP_AND);
  21
  22   $database->enquire($qp->parse_query('a NEAR word OR "a phrase" NOT (too difficult) +eh'));
  23
  24 =head1 METHODS
  25
  26 =over 4
  27
  28 =item new <database>
  29
  30 QueryParser constructor.
  31
  32 =item set_stemmer <stemmer>
  33
  34 Set the Xapian::Stem object to be used for stemming query terms.
  35
  36 =item set_stemming_strategy <strategy>
  37
  38 Set the stemming strategy.  Valid values are C<STEM_ALL>, C<STEM_SOME>,
  39 C<STEM_NONE>.
  40
  41 =item set_stopper <stopper>
  42
  43 Set the Xapian::Stopper object to be used for identifying stopwords.
  44
  45 =item set_default_op <operator>
  46
  47 Set the default operator.
  48
  49 This operator is used to combine non-filter query items when no
  50 explicit operator is used.
  51
  52 The most useful values for this are OP_OR (the default) and OP_AND.
  53 OP_NEAR and OP_PHRASE can also be useful.
  54
  55 See L<Xapian> for descriptions of these constants.
  56
  57 =item get_default_op
  58
  59 Returns the current default operator.
  60
  61 =item set_database <database>
  62
  63 Pass a L<Xapian::Database> object which is used to check whether
  64 terms exist in some situations.
  65
  66 =item parse_query <query_string> [<flags>]
  67
  68 Parses the query string according to the rules defined in the query parser
  69 documentation below. You can specify certain flags to modify the
  70 searching behaviour:
  71
  72   FLAG_BOOLEAN, FLAG_PHRASE, FLAG_LOVEHATE, FLAG_BOOLEAN_ANY_CASE,
  73   FLAG_WILDCARD, FLAG_PURE_NOT, FLAG_PARTIAL, FLAG_SPELLING_CORRECTION,
  74   FLAG_SYNONYM, FLAG_AUTO_SYNONYMS, FLAG_AUTO_MULTIWORD_SYNONYMS,
  75   FLAG_CJK_NGRAM
  76
  77 To specify multiple flags, "bitwise or" them together (with C<|>).  The
  78 default flags are C<FLAG_PHRASE|FLAG_BOOLEAN|FLAG_LOVEHATE>
  79
  80 =item add_prefix <field> <prefix>
  81
  82 Add a term prefix mapping.  E.g. $qp->add_prefix("author", "A");
  83
  84 Allows the user to search for author:orwell which will search for the term
  85 "Aorwel" (assuming English stemming is in use). Multiple fields can be mapped
  86 to the same prefix (so you can e.g. make title: and subject: aliases for each
  87 other).
  88
  89 Parameters:
  90 field   The user visible field name
  91 prefix  The term prefix to map this to
  92
  93 =item add_boolean_prefix <field> prefix
  94
  95 Add a boolean term prefix mapping, allowing the user to restrict a search with
  96 a boolean filter specified in the free text query.  E.g.
  97
  98   $p->add_boolean_prefix("site", "H");
  99
 100 Allows the user to restrict a search with site:xapian.org which will be
 101 converted to Hxapian.org combined with the rest of the parsed query using
 102 C<OP_FILTER>.
 103
 104 Multiple fields can be mapped to the same prefix (so you can e.g. make site:
 105 and domain: aliases for each other).
 106
 107 Parameters:
 108 field   The user visible field name
 109 prefix  The term prefix to map this to
 110
 111 =item stoplist_begin
 112
 113 =item stoplist_end
 114
 115 =item unstem_begin
 116
 117 =item unstem_end
 118
 119 =item get_description
 120
 121 Returns a string describing this object.
 122
 123 =item get_corrected_query_string
 124
 125 Get the spelling-corrected query string.
 126
 127 This will only be set if FLAG_SPELLING_CORRECTION is specified when
 128 QueryParser::parse_query() was last called.
 129
 130 If there were no corrections, an empty string is returned.
 131
 132 =item set_max_wildcard_expansion <limit>
 133
 134 Specify the maximum expansion of a wildcard term.
 135
 136 Note: you must also set FLAG_WILDCARD for wildcard expansion to happen.
 137
 138 Parameter limit is the maximum number of terms each wildcard in the query can
 139 expand to, or 0 for no limit (which is the default).
 140
 141 =cut
 142
 143 =back
 144
 145 =head1 REFERENCE
 146
 147   https://xapian.org/docs/queryparser.html
 148   https://xapian.org/docs/sourcedoc/html/classXapian_1_1QueryParser.html
 149
 150 =cut
 151 1;