regexps ending with $

[MarkWeberMaths]

Hello. Thanks for this package.

I have experienced some strange behaviour when trying to narrow my search using $ at the end of a regexp. For instance if I have a bunch of .ts and .tsx files open, and when using consult-buffer, I'd like to narrow my search to buffer names ending in 'ts' by typing 'ts$' in the search interface. For me this gives no matches. However I experience no problems using ^ at the beginning of a regexp, in such cases search narrowing works as you'd expect. When experimenting with more examples I get inconsistent behaviours -- all of the following regexps should narrow to buffers whose names end in 'ts' -- 'ts$', '[t]s$', 'ts[^x]$', 'ts[^y]$', '[t]s[^z]$ -- but for me, the first 2 give no matches, but the last 3 do successfully match the buffer names ending in 'ts'.

[oantolin]

This is actually not a bug in orderless at all, but something caused by an implementation detail in consult-buffer: it appends an invisible character to the end of the candidates for disambiguation. So if you have a buffer called heap.ts the consult-buffer candidate is actually called something like heap.ts# where the # stands for some weird unicode character which consult arranges to be invisible using Emacs display properties. Knowing this you can easily see why ts$ and [t]s$ don't match but the regexps like ts[^x]$ do:

• ts$ and [t]s$ match strings that end in ts, so they do not match strings ending in weird character I'm denoting #.
• ts[^x]$ does match, because [^x] matches the # character.

(Note that you said ts[^x]$ should match names ending in ts, but that of course is not true, because if a name ends in ts, then its last character, namely s, does match [^x]; but the previous one ,t, does not match s.)

The simplest work around is to use a . to match the invisible character added by consult-buffer: the regexp ts.$ matches your buffers. More sophisticated workarounds are documented in the consult wiki.

[MarkWeberMaths]

Great! Thanks for the explanation. Might I suggest adding something about this in the orderless documentation, since from the user's prespective this does look at first glance like a bug in orderless? For instance, when reaching the orderless github page in my browser, it would be good if searching on '$' would bring me to this information.

Thanks again.