feature_flag

Support AND, OR, etc and bracketed subexpressions.

Support quoted phrases.

Support + and -.

Support AND, OR, etc even if they aren't in ALLCAPS.

Support right truncation (e.g. Xap*).

Currently you can't use wildcards with boolean filter prefixes, or in a phrase (either an explicitly quoted one, or one implicitly generated by hyphens or other punctuation).

NB: You need to tell the QueryParser object which database to expand wildcards from by calling set_database.

Allow queries such as 'NOT apples'.

These require the use of a list of all documents in the database which is potentially expensive, so this feature isn't enabled by default.

Enable partial matching.

Partial matching causes the parser to treat the query as a "partially entered" search. This will automatically treat the final word as a wildcarded match, unless it is followed by whitespace, to produce more stable results from interactive searches.

Currently FLAG_PARTIAL doesn't do anything if the final word in the query has a boolean filter prefix, or if it is in a phrase (either an explicitly quoted one, or one implicitly generated by hyphens or other punctuation). It also doesn't do anything if if the final word is part of a value range.

NB: You need to tell the QueryParser object which database to expand wildcards from by calling set_database.

Enable spelling correction.

For each word in the query which doesn't exist as a term in the database, Database::get_spelling_suggestion() will be called and if a suggestion is returned, a corrected version of the query string will be built up which can be read using QueryParser::get_corrected_query_string(). The query returned is based on the uncorrected query string however - if you want a parsed query based on the corrected query string, you must call QueryParser::parse_query() again.

NB: You must also call set_database() for this to work.

Enable synonym operator '~'.

NB: You must also call set_database() for this to work.

Enable automatic use of synonyms for single terms.

NB: You must also call set_database() for this to work.

Enable automatic use of synonyms for single terms and groups of terms.

NB: You must also call set_database() for this to work.

The default flags.

Used if you don't explicitly pass any to @a parse_query(). The default flags are FLAG_PHRASE|FLAG_BOOLEAN|FLAG_LOVEHATE.

Added in Xapian 1.0.11.