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[Python-ideas] re.compile_lazy - on first use compiled regexes

Steven D'Aprano steve at pearwood.info
Thu Mar 28 02:56:20 CET 2013 
On 28/03/13 12:38, Chris Angelico wrote:
> On Thu, Mar 28, 2013 at 12:25 PM, Steven D'Aprano <steve at pearwood.info> wrote:
>> We do this:
>>
>> x = Decimal(some_string)
>> y = x**3
>> z = x.exp()
>>
>> not this:
>>
>> y = Decimal(some_string)**3
>> z = Decimal(some_string).exp()
>>
>> hoping that the string will be in a cache and the conversion will be fast.
>> So why do we do this?
>>
>> result = re.match(some_string, text)
>> other_result = re.match(some_string, other_text)
>
> Would it be better if, instead of:
>
> pat = re.compile(some_string)
>
> it were spelled:
>
> pat = re.RegExp(some_string)
>
> ? It'd match Decimal and so on, while still being exactly the same
> thing ultimately - you turn the textual regex into an object.


No, you seem to have missed my point.

I don't care whether we have a builder like re.compile() that turns a string into a regular expression object, or we use the RegExp type constructor directly. What I care about is that we don't recommend that people rely on the cache to handle that conversion, as Terry seems to be suggesting.



-- 
Steven
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