match if equal?

[zlee-personal]

Is there a way to match a pattern like [_, 0, _] only if the two _s are equal, and if they aren't continue to the next pattern?

[hucker]

Not nicely as far as I can tell.

the best I could come up with is:

def check_seq(seq):
    return len(seq)==3 and seq[1] == 0 and seq[0]==seq[2]

def match_seq(seq):
    return 2* seq[0]

and then have the pattern just be check_seq...then you end up with:
check_seq, lambda a: match_seq(a)

This isn't great because you loose the patterns but it is compact.