Alex Martelli wrote:
class ReWithMemory(object):
    def search(self, are, aline):
        self.mo = re.search(are, aline)
        return self.mo
    def group(self, n):
        return self.mo.group(n)

m = ReWithMemory()

if m.search(r'add (\d+) (\d+)', line):
    do_add(m.group(1), m.group(2))
elif m.search(r'mult (\d+) (\d+)', line):
    do_mult(m.group(1), m.group(2))
elif m.search(r'help (\w+)', line):
    show_help(m.group(1))

Demeter's Law suggests that the 'm.value.group' accesses in your
approach are better handled by having m delegate to its `value'; and the
repeated m.set(re.search( ... seem to be a slight code smell, violating
"once and only once", which suggests merging into a single `set' method.
Your approach is more general, of course.

I get a bit uneasy from the repeated calls to m.group... If I was going to build a class around the re, I think I might lean towards something like:


class ReWithMemory(object):
    def search(self, are, aline):
        self.mo = re.search(are, aline)
        return self.mo
    def groups(self, *indices):
        return [self.mo.group(i) for i in indices]

m = ReWithMemory()

if m.search(r'add (\d+) (\d+)', line):
    do_add(*m.groups(1, 2))
elif m.search(r'mult (\d+) (\d+)', line):
    do_mult(*m.groups(1, 2))
elif m.search(r'help (\w+)', line):
    show_help(*m.groups(1))

Of course, this is even less general-purpose than yours...

(And if I saw myself using this much regex code, I'd probably reconsider my strategy anyway.) ;)

Steve
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