parser: add helper function to test if pattern matches parsed tree This function will be used as follows: match('ancestors(_) and not ancestors(_)', x) See the next patch for details.

revsetlang: build optimized tree by helper function This should make optimize() more readable, but it doubles the parsing cost. (original) $ python -m timeit -n10000 -s 'from mercurial import revsetlang as L' \ 'L.optimize(L.analyze(L.parse("::tip")))' 10000 loops, best of 3: 18.1 usec per loop (this patch) $ python -m timeit -n10000 -s 'from mercurial import revsetlang as L' \ 'L._treecache.clear(); L.optimize(L.analyze(L.parse("::tip")))' 10000 loops, best of 3: 48.4 usec per loop 30usec isn't dominant compared to the revset evaluation, but that is a cost. That's why a parsed tree is cached, which can benefit in hgweb or chg server.

parser: add helper function that constructs parsed tree from template This function will be used as follows: build('only(_, _)', x, y) See the next patch for details.