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[Python-Dev] IDLE colorizer


[MRAB <python at mrabarnett.plus.com>[
> A thread on python-ideas is talking about the prefixes of string literals,
> and the regex used in IDLE.
>
> Line 25 of Lib\idlelib\colorizer.py is:
>
>     stringprefix = r"(?i:\br|u|f|fr|rf|b|br|rb)?"
>
> which looks slightly wrong to me.
>
> The \b will apply only to the first choice.
>
> Shouldn't it be more like:
>
>     stringprefix = r"(?:\b(?i:r|u|f|fr|rf|b|br|rb))?"
>
> ?

I believe the change would capture its real intent.  It doesn't seem
to matter a whole lot, though - IDLE isn't a syntax checker, and
applies heuristics to color on the fly based on best guesses.  As is,
if you type this fragment into an IDLE shell:

kr"sdf"

only the last 5 characters get "string colored", presumably because of
the leading \br in the original regexp.  But if you type in

ku"sdf"

the last 6 characters get "string colored", because - as you pointed
out - the \b part of the original regexp has no effect on anything
other than the r following \b.

But in neither case is the fragment legit Python.  If you do type in
legit Python, it makes no difference (legit string literals always
start at a word boundary, regardless of whether the regexp checks for
that).