def unify_single(t1, t2, solution, remaining):
"""
Unify a single type equation and update the solution and remaining
constraints.
"""
if isinstance(t1, TypeVar) and isinstance(t2, TypeVar):
remaining.append((t1, t2))
elif isinstance(t1, TypeVar):
if t1 in free(t2):
raise error.UnificationError("Cannot unify recursive types")
solution[t1].add(t2)
remaining.append((t1, t2))
elif isinstance(t2, TypeVar):
if t2 in free(t1):
raise error.UnificationError("Cannot unify recursive types")
solution[t2].add(t1)
elif isinstance(t1, TypeConstructor):
verify(t1, t2)
elif not free(t1) and not free(t2):
# No need to recurse, this will be caught by promote()
pass
else:
verify(t1, t2)
for arg1, arg2 in zip(t1.parameters, t2.parameters):
unify_single(arg1, arg2, solution, remaining)
def tzip(f, a, b, descend=descend):
"""Map f over two types zip-wise"""
from blaze.datashape import verify # TODO: remove circularity
if not descend(a) or not descend(b):
return a, b
verify(a, b)
result = zip(*starmap(f, zip(a.parameters, b.parameters)))
params1, params2 = result or [(), ()]
return (type_constructor(a)(*params1), type_constructor(b)(*params2))
def tzip(f, a, b, descend=descend):
"""Map f over two types zip-wise"""
from blaze.datashape import verify # TODO: remove circularity
if not descend(a) or not descend(b):
return a, b
verify(a, b)
params1, params2 = zip(*[
f(arg1, arg2) for arg1, arg2 in zip(a.parameters, b.parameters)])
return (type_constructor(a)(*params1), type_constructor(b)(*params2))
def promote_type_constructor(a, b):
"""Promote two generic type constructors"""
# Verify type constructor equality
verify(a, b)
# Promote parameters according to flags
args = []
for flag, t1, t2 in zip(a.flags, a.parameters, b.parameters):
if flag['coercible']:
result = promote(t1, t2)
else:
if t1 != t2:
raise error.UnificationError(
"Got differing types %s and %s for unpromotable type "
"parameter" % (t1, t2))
result = t1
args.append(result)
return type(a)(*args)
def unify_single(t1, t2, solution, remaining):
"""
Unify a single type equation and update the solution and remaining
constraints.
"""
if isinstance(t1, TypeVar) and isinstance(t2, TypeVar):
remaining.append((t1, t2))
elif isinstance(t1, TypeVar):
if t1 in free(t2):
raise error.UnificationError("Cannot unify recursive types")
solution[t1].add(t2)
remaining.append((t1, t2))
elif isinstance(t2, TypeVar):
if t2 in free(t1):
raise error.UnificationError("Cannot unify recursive types")
solution[t2].add(t1)
elif isinstance(t1, TypeConstructor):
verify(t1, t2)
elif not isinstance(t1, Mono) and not isinstance(t2, Mono):
verify(t1, t2)
elif getattr(t1, "cls", None) == MEASURE and getattr(t2, "cls", None) == MEASURE:
# If both types are measures, verify they can be promoted
promote_units(t1, t2)
else:
verify(t1, t2)
for arg1, arg2 in zip(t1.parameters, t2.parameters):
unify_single(arg1, arg2, solution, remaining)
