[Python-Dev] IDLE colorizer
On 4/1/2018 10:20 PM, Tim Peters wrote:
> [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.
This must be a holdover from years ago, before I was involved. I have
wondered about it but left it as is. Thanks for confirming that it is
>> 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:
> only the last 5 characters get "string colored", presumably because of
> the leading \br in the original regexp. But if you type in
> 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.
I tested with uf versus ur, which are both plausibly legal but are not.
> 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
I want uniform behavior. I decided to drop the \b because I prefer
coloring the maximal legal string rather than the minimum. I think the
contrast between two chars legal by themselves, but differently colored
when put together, makes the bug more obvious.
Terry Jan Reedy