Parsing of hex encoding strings

Hello,

I’m working on a system where I need to search for hex encoded strings, for which I’m using full text search with the “simple” directory. This is working fine for the most part, but I’ve run into an issue which may or may not be considered a bug.

When creating the ts vector and queries I want to achieve that the entire hex encoded string is seen as a single word. For a string such as “fe82fbb28” this works using the “simple” directory. However a string such as “7e82fbb28” is parsed as two words: “7e82” as scientific notation and “fbb28" as numword. I’ve put the output of ts_debug at the bottom of this email for convince.

I would have expected that the entire string would be considered as one token considering it doesn’t have any whitespace. And since that token isn’t a valid scientific number as whole (though it can be, just not the examples I’ve shared above) I would expected it be considered a single word (numword). Reading the URL example from chapter 12.5 (https://www.postgresql.org/docs/current/textsearch-parsers.html) maybe it could have to two tokens, one for the scientific number (“7e82”) and another numword token for the entire string (7e82fbb28”), this would also work for my use case.

Finally, my question: is this considered behaviour a bug or working as intended?

Output of ts_debug:

— Wanted result.
SELECT * FROM ts_debug('fe82fbb28');
+---------+--------------------------+-----------+--------------+------------+-------------+
| alias | description | token | dictionaries | dictionary | lexemes |
+---------+--------------------------+-----------+--------------+------------+-------------+
| numword | Word, letters and digits | fe82fbb28 | {simple} | simple | {fe82fbb28} |
+---------+--------------------------+-----------+--------------+------------+-------------+

— Unwanted scientific notation.
SELECT * FROM ts_debug('7e82fbb28');
+---------+--------------------------+-------+--------------+------------+---------+
| alias | description | token | dictionaries | dictionary | lexemes |
+---------+--------------------------+-------+--------------+------------+---------+
| sfloat | Scientific notation | 7e82 | {simple} | simple | {7e82} |
| numword | Word, letters and digits | fbb28 | {simple} | simple | {fbb28} |
+---------+--------------------------+-------+--------------+------------+---------+

With kind regards,

Thomas de Zeeuw