mndrix/regex

Support rhs variables

Closed this issue · 2 comments

fnogatz commented

Apparently variables are not supported on the right-hand side of the =~ operator:

?- Pattern = '[a-z]', S = 'a', S =~ '[a-z]'.
Pattern = '[a-z]',
S = a.

?- Pattern = '[a-z]', S = 'a', S =~ Pattern.
false.

I am not sure whether this is a bug or as designed.

It is possible to use regex/4 instead, which trivially supports variables: regex(Pattern,[],S,_). Nevertheless, regex/4 is not documented in the README at all :)

mndrix commented

Thanks for letting me know. It looks like a bug to me. =~ is supposed to be sugar on top of regex/4 so they should be functionally equivalent. Unfortunately, I'm traveling for the next couple weeks and don't have access to an SWI-Prolog installation for testing a fix. If you have any time to investigate further, that'd be great.

Nevertheless, regex/4 is not documented in the README at all

The README is designed to give a summary of the package rather than a complete specification. The full documentation does mention regex/4.

mndrix commented

Fixed in release v0.3.3