Re: template strings for matching?

[Robin Becker]

Joe Strout wrote:

Catching up on what's new in Python since I last used it a decade ago,
I've just been reading up on template strings. These are pretty cool!
However, just as a template string has some advantages over %
substitution for building a string, it seems like it would have
advantages over manually constructing a regex for string matching.
>
So... is there any way to use a template string for matching? I
expected something like:

........

you could use something like this to record the lookups

>>class XDict(dict):

.... def __new__(cls,*ar gs,**kwds):
.... self = dict.__new__(cl s,*args,**kwds)
.... self.__record = set()
.... return self
.... def _record_clear(s elf):
.... self.__record.c lear()
.... def __getitem__(sel f,k):
.... v = dict.__getitem_ _(self,k)
.... self.__record.a dd(k)
.... return v
.... def _record(self):
.... return self.__record
....

>>x=XDict()
>>x._record()

set([])

>>x=XDict(a=1,b =2,c=3)
>>x

{'a': 1, 'c': 3, 'b': 2}

>>'%(a)s %(c)s' % x

'1 3'

>>x._record()

set(['a', 'c'])

>>>

a slight modification would allow your template match function to work even when
some keys were missing in the dict. That would allow you to see which lookups
failed as well.
--
Robin Becker