[Python-ideas] PEP 8: raw strings & regular expressions

[Ned Batchelder]

On 10/26/15 3:23 AM, Alexander Walters wrote:
>
> On 10/23/2015 14:40, Ned Batchelder wrote:
>> On 10/22/15 6:56 PM, Yury Selivanov wrote:
>>> In principle, there is no reason why *both* of these groups
>>> of users can't use one tool and be happy.  I propose to
>>> establish a convention in PEP 8, explaining that, while both
>>> literals are semantically equivalent,
>>>
>>> - r'..' strings *should* be used for regexps,
>>>
>>> - R'..' strings *should* be used for unstyled raw strings,
>>>
>>> and tools *should* treat them as such.
>>>
>>> All of this is merely about codifying the current status quo. 
>> But you are not codifying the status quo.  The distinction you are 
>> proposing is one that you have invented.  I have never used R"" strings.
>>
>> I think the best solution to the problem is to improve the 
>> highlighters, and luckily you have written one!  To me, it is clear 
>> which of these strings is the regex:
>>
>>     r"\d+"
>>     r"\dir"
>>
>> If the highlighters tried some heuristics, they could do a better job 
>> "being helpful" by making better guesses about the meaning of 
>> programs.  I don't mind when highlighters make wrong guesses, as long 
>> as they don't ruin the entire rest of the file.  But better guesses 
>> will be better. :)
>>
>> --Ned.
>>
>
> it should be noted that most regexes are also valid paths on NTFS.  is 
> r'\dir[a-zA-Z0-9]\\' a path or a regex?
I understand developers' penchant for getting everything precisely right 
and accounting for the darkest of corners and the farthest reaches of 
obscure edge cases.  But I'm talking about making a reasonable guess.  
If the string contains square brackets, especially paired brackets with 
hyphens inside, it's probably a regex.

--Ned.
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