def top_down(brule, fns=basic_fns):
""" Apply a rule down a tree running it on the top nodes first """
return chain(do_one(brule, identity),
lambda expr: sall(top_down(brule, fns), fns)(expr))
def top_down(brule, fns=basic_fns):
""" Apply a rule down a tree running it on the top nodes first """
return chain(do_one(brule, identity),
lambda expr: sall(top_down(brule, fns), fns)(expr))
def chain(self,f):
return core.chain(self,f)
