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expose re._parse.parse_template publicly #105636
Description
Feature or enhancement
I would like to access parse_template to be able to eagerly validate that a regex replacement template is valid.
I'm using this in my python-based text editor to do find and replace. Currently I am reaching into sre_parse to get parse_template (which used to be a public-named module but was deprecated in 3.11)
I suspect this could be as simple as exposing parse_template -- my code doesn't actually care about the return value, simply whether it raises an exception or not
Activity
sobolevn commentedon Jun 11, 2023
Refs #105456
AlexWaygood commentedon Jun 11, 2023
Cc. @serhiy-storchaka
raghunandanbhat commentedon Jun 14, 2023
I started working on this and added
parse_template()inre.__init__.pyConsidering the very limited amount of documentation about this function, I would appreciate some help in testing it thoroughly and writing detailed documentation.
serhiy-storchaka commentedon Jun 14, 2023
Is regex replacement template validation only what you need? Or do you need more information from the result?
Over a year ago, I wrote an implementation to compile a regex replacement template. I expected that this could be used to speed up critical code, like
re.compile(), but I didn't see much difference compared to implicitly caching the compiled regex replacement templates. So I excluded it from #91524.asottile commentedon Jun 14, 2023
personally I only care about validation
raghunandanbhat commentedon Jul 1, 2023
Since the
parse_template()raises an error when replacement template is invalid, we could just useparse_template()as it is by exposing it publicly.I think it is redundant to implement a function just to check if a replacement template is valid, instead we could use the existing one as it is.
pythongh-105636: Add re.Pattern.compile_template()
pythongh-105636: Add re.Pattern.compile_template()
serhiy-storchaka commentedon Jun 26, 2025
#135992 it is almost the same as the version written 4 years ago. It adds the
compile_template()method for the pattern object which simply calls private functionre._compile_template(). The type of the result is exposed asre.Template. It has minimal interface:__call__and__class_getitem__.asottile commentedon Jun 26, 2025
ah nice! that would definitely solve my problem
asottile commentedon Jun 17, 2026
unfortunate this won't make it to 3.15 (since the sre_* modules are gone gone now) -- will have to resort to some hacks until this api gets included :(