Re: compiled regex as attribute

Have you done any performance testing? From what I understand pythons
re.compile caches internally, so after the first call subsequent calls
will use the pre-compiled expression. Serializing the compiled
expression using pickle isn't 'free', so I'm wondering how much
difference there is in practice. Maybe a compromise of a normal model
text field storing the regular expression string you build when the
model is saved, and then a propery to simulate a read-only/don-demand
the compiled version when you need it.

ie something like:

class Product(models.Model):
# ...
canonical_name = models.CharField(max_length=200)
spelling_variants = models.CharField(max_length=10000, blank=True)
lexical_variants = models.CharField(max_length=10000, blank=True)
excluded = models.CharField(max_length=10000, blank=True)
permutations = models.CharField(max_length=1000, blank=True)
re_str=models.TextField()

compiled_re=property(lambda p: re.compile(p.re_str))

def save(self,*args,**kwargs):
# do your regular expression string build here and store in
self.re_str

Although it seems to me like each variant propably belongs as a
separate model, linking to your product. That way you can search on
it, and add/remove variants fairly easily. To match now, you'd have
to pull a bunch of products in a query and test each one. The
database server isn't going to sweat a few hundred or even thousand
names.

class Variant(models.Model):
name=models.CharField(db_index=True)
product=models.ForeignKey(Product)

Product.objects.filter(variant__name='oha android 1.1')

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