def build_rule(l, r, cons=None):
lpat = []
rpat = []
sym = set()
cons = cons or {}
for pat, bind, ty in free(l):
if bind in sym:
# TODO unify ty
lpat.append(bind)
else:
lpat.append(bind)
sym.add(bind)
for pat, bind, ty in free(r):
if bind in sym:
rpat.append(bind)
else:
raise Exception('Unbound variable: %s' % pat)
left = freev(l)
right = freev(r)
ana = partial(unfold, lpat, left)
cata = partial(fold, rpat, right)
rr = partial(hylo, ana, cata)
return Rule(lpat, rpat, left, right, rr)
def main():
parser = argparse.ArgumentParser()
parser.add_argument('module', nargs='?', help='Module')
parser.add_argument('--noprelude',
action='store_true',
help='Include prelude')
args = parser.parse_args()
# State
mod = {}
last = None
bindings = {}
if args.module:
with open(args.module) as fd:
mod = module(fd.read())
if not args.noprelude:
mod.update(prelude)
print banner
readline.parse_and_bind("tab: complete")
readline.set_completer(partial(completer, mod))
while True:
try:
line = raw_input('>> ').strip()
except EOFError:
break
#-----------------------------------------------
if line.startswith('?'):
at = aparse(line[1:])
matcher = partial(match, freev(at))
matched, localbind = matcher(last)
# TODO: Use dict
#bindings.update(localbind)
#if matched:
# print bindings
#else:
# print 'failed'
#-----------------------------------------------
elif line.startswith('!'):
try:
rr = mod[line[1:].strip()]
last = rr.rewrite(last)
print last
except KeyError:
print "No such rule or strategy '%s'" % line[1:]
except NoMatch:
print 'failed'
#-----------------------------------------------
elif line.startswith(':show') or line.startswith(':s'):
try:
rr = mod[line[1:].strip()]
print rr
except KeyError:
print "No such rule or strategy '%s'" % line[1:]
#-----------------------------------------------
elif line.startswith(':type') or line.startswith(':t'):
try:
at = aparse(line[2:])
print type(at).__name__
except Exception as e:
print e
#-----------------------------------------------
elif line.startswith(':bindings'):
if bindings:
pprint.pprint(bindings)
continue
#-----------------------------------------------
elif line.startswith(':let'):
env = module(line[4:], _env=mod)
mod.update(env)
#-----------------------------------------------
elif line.startswith(':load'):
fname = line[5:].strip()
try:
contents = open(fname).read()
mod.update(module(contents))
except IOError:
print "No such module", fname
#-----------------------------------------------
elif line.startswith(':browse'):
pprint.pprint(mod)
#-----------------------------------------------
elif line.startswith(':help'):
print help
pass
#-----------------------------------------------
else:
bindings = {}
try:
last = aparse(line)
print last
except EOFError:
pass
except Exception as e:
print traceback.format_exc()
