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F.30. test_parsertest_parser is an example of a custom parser for full-text search. It doesn't do anything especially useful, but can serve as a starting point for developing your own parser. test_parser recognizes words separated by white space, and returns just two token types: mydb=# SELECT * FROM ts_token_type('testparser');
tokid | alias | description
-------+-------+---------------
3 | word | Word
12 | blank | Space symbols
(2 rows)
These token numbers have been chosen to be compatible with the default
parser's numbering. This allows us to use its F.30.1. UsageRunning the installation script creates a text search parser testparser. It has no user-configurable parameters. You can test the parser with, for example, mydb=# SELECT * FROM ts_parse('testparser', 'That''s my first own parser');
tokid | token
-------+--------
3 | That's
12 |
3 | my
12 |
3 | first
12 |
3 | own
12 |
3 | parser
Real-world use requires setting up a text search configuration that uses the parser. For example, mydb=# CREATE TEXT SEARCH CONFIGURATION testcfg ( PARSER = testparser );
CREATE TEXT SEARCH CONFIGURATION
mydb=# ALTER TEXT SEARCH CONFIGURATION testcfg
mydb-# ADD MAPPING FOR word WITH english_stem;
ALTER TEXT SEARCH CONFIGURATION
mydb=# SELECT to_tsvector('testcfg', 'That''s my first own parser');
to_tsvector
-------------------------------
'that':1 'first':3 'parser':5
(1 row)
mydb=# SELECT ts_headline('testcfg', 'Supernovae stars are the brightest phenomena in galaxies',
mydb(# to_tsquery('testcfg', 'star'));
ts_headline
-----------------------------------------------------------------
Supernovae <b>stars</b> are the brightest phenomena in galaxies
(1 row)
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