#!/bin/sh

cat > engine.py << EOF

from mercurial import templater

class mytemplater(object):

    def __init__(self, loader, filters, defaults):

        self.loader = loader

    def process(self, t, map):

        tmpl = self.loader(t)

        for k, v in map.iteritems():

            if k in ('templ', 'ctx', 'repo', 'revcache', 'cache'):

                continue

            if hasattr(v, '__call__'):

                v = v(**map)

            v = templater.stringify(v)

            tmpl = tmpl.replace('{{%s}}' % k, v)

        yield tmpl

templater.engines['my'] = mytemplater

EOF

hg init test

echo '[extensions]' > test/.hg/hgrc

echo "engine = `pwd`/engine.py" >> test/.hg/hgrc

cd test

cat > mymap << EOF

changeset = my:changeset.txt

EOF

cat > changeset.txt << EOF

{{rev}} {{node}} {{author}}

EOF

hg ci -Ama

hg log --style=./mymap