template strings for matching?

[Paul McGuire]

Pyparsing makes building expressions with named fields pretty easy.

from pyparsing import Word, alphas

wrd = Word(alphas)

templ = "The" + wrd("object") + "in" + wrd("location") + \
    "stays mainly in the" + wrd("subloc") + "."

tests = """\
    The rain in Spain stays mainly in the plain.
    The snake in plane stays mainly in the cabin.
    In Hempstead, Haverford and Hampshire hurricanes hardly ever
happen.
    """.splitlines()
for t in tests:
    t = t.strip()
    try:
        match = templ.parseString(t)
        print match.object
        print match.location
        print match.subloc
        print "Fields are: %(object)s %(location)s %(subloc)s" % match
    except:
        print "'" + t + "' is not a match."
    print

Read more about pyparsing at http://pyparsing.wikispaces.com.
-- Paul