- NAME
- DESCRIPTION
- SYNOPSIS
- METHODS
- REFERENCE

# NAME

Xapian::QueryParser - Parse a query string into a Xapian::Query object

# DESCRIPTION

This module turns a human readable string into something Xapian can understand. The syntax supported is designed to be similar to other web based search engines, so that users familiar with them don't have to learn a whole new syntax.

# SYNOPSIS

    use Xapian qw/:standard/;

    my $qp = new Xapian::QueryParser( [$database] );
    $qp->set_stemmer(new Xapian::Stem("english"));
    $qp->set_default_op(OP_AND);

    $database->enquire($qp->parse_query('a NEAR word OR "a phrase" NOT (too difficult) +eh'));

# METHODS

new <database>

  QueryParser constructor.

set_stemmer <stemmer>

  Set the Xapian::Stem object to be used for stemming query terms.

set_stemming_strategy <strategy>

  Set the stemming strategy. Valid values are `STEM_ALL`, `STEM_SOME`, `STEM_NONE`.

set_stopper <stopper>

  Set the Xapian::Stopper object to be used for identifying stopwords.

set_default_op <operator>

  Set the default operator.

  This operator is used to combine non-filter query items when no explicit operator is used.

  The most useful values for this are OP_OR (the default) and OP_AND. OP_NEAR and OP_PHRASE can also be useful.

  See Xapian for descriptions of these constants.

get_default_op

  Returns the current default operator.

set_database <database>

  Pass a Xapian::Database object which is used to check whether terms exist in some situations.

parse_query <query_string> [<flags>]

  Parses the query string according to the rules defined in the query parser documentation below. You can specify certain flags to modify the searching behaviour:

      FLAG_DEFAULT, FLAG_ACCUMULATE, FLAG_BOOLEAN, FLAG_FUZZY,
      FLAG_NO_POSITIONS, FLAG_PHRASE, FLAG_LOVEHATE, FLAG_BOOLEAN_ANY_CASE,
      FLAG_WILDCARD, FLAG_PURE_NOT, FLAG_PARTIAL, FLAG_SPELLING_CORRECTION,
      FLAG_WILDCARD_GLOB, FLAG_WILDCARD_MULTI, FLAG_WILDCARD_SINGLE,
      FLAG_SYNONYM, FLAG_AUTO_SYNONYMS, FLAG_AUTO_MULTIWORD_SYNONYMS,
      FLAG_NGRAMS, FLAG_WORD_BREAKS, FLAG_CJK_NGRAM, FLAG_NO_PROPER_NOUN_HEURISTIC

  To specify multiple flags, "bitwise or" them together (with `|`). The default flags are `FLAG_DEFAULT` which is equivalent to `FLAG_PHRASE|FLAG_BOOLEAN|FLAG_LOVEHATE`.

add_prefix <field> <prefix>

  Add a term prefix mapping. E.g. $qp->add_prefix("author", "A");

  Allows the user to search for author:orwell which will search for the term "Aorwel" (assuming English stemming is in use). Multiple fields can be mapped to the same prefix (so you can e.g. make title: and subject: aliases for each other).

  Parameters: field The user visible field name prefix The term prefix to map this to

add_boolean_prefix <field> prefix

  Add a boolean term prefix mapping, allowing the user to restrict a search with a boolean filter specified in the free text query. E.g.

      $p->add_boolean_prefix("site", "H");

  Allows the user to restrict a search with site:xapian.org which will be converted to Hxapian.org combined with the rest of the parsed query using `OP_FILTER`.

  Multiple fields can be mapped to the same prefix (so you can e.g. make site: and domain: aliases for each other).

  Parameters: field The user visible field name prefix The term prefix to map this to

stoplist_begin
stoplist_end
unstem_begin
unstem_end
get_description

  Returns a string describing this object.

get_corrected_query_string

  Get the spelling-corrected query string.

  This will only be set if FLAG_SPELLING_CORRECTION is specified when QueryParser::parse_query() was last called.

  If there were no corrections, an empty string is returned.

set_max_wildcard_expansion <limit>

  Specify the maximum expansion of a wildcard term.

  Note: you must also set FLAG_WILDCARD for wildcard expansion to happen.

  Parameter limit is the maximum number of terms each wildcard in the query can expand to, or 0 for no limit (which is the default).

# REFERENCE

    https://xapian.org/docs/queryparser.html
    https://xapian.org/docs/sourcedoc/html/classXapian_1_1QueryParser.html