Re: tsearch2 and hyphenated terms

Reece Hart <reece(at)harts(dot)net> writes:
> For the purposes of indexing these names, I suspect I'd get the majority
> of cases by removing a hyphen when it's followed by 1 or 2 chars from
> [a-zA-Z0-9]. Does that require a custom parser?

Yeah, looks like it:

regression=# select * from ts_debug('MCL1 MCL-1');
alias | description | token | dictionaries | dictionary | lexemes
-----------+--------------------------+-------+----------------+--------------+---------
numword | Word, letters and digits | MCL1 | {simple} | simple | {mcl1}
blank | Space symbols | | {} | |
asciiword | Word, all ASCII | MCL | {english_stem} | english_stem | {mcl}
int | Signed integer | -1 | {simple} | simple | {-1}
(4 rows)

I had thought you might get a "numhword" output, but that only seems to
happen if there's at least one letter after the dash:

regression=# select * from ts_debug('MCL1 MCL-X1');
alias | description | token | dictionaries | dictionary | lexemes
-----------------+------------------------------------------+--------+----------------+--------------+----------
numword | Word, letters and digits | MCL1 | {simple} | simple | {mcl1}
blank | Space symbols | | {} | |
numhword | Hyphenated word, letters and digits | MCL-X1 | {simple} | simple | {mcl-x1}
hword_asciipart | Hyphenated word part, all ASCII | MCL | {english_stem} | english_stem | {mcl}
blank | Space symbols | - | {} | |
hword_numpart | Hyphenated word part, letters and digits | X1 | {simple} | simple | {x1}
(6 rows)

regards, tom lane