def test_monad_laws():
"Test if the basic monadic functions conform to the three Monad Laws."
from hornet.expressions import unit, bind, lift
x = ast.Name(id='x', ctx=load)
y = ast.Name(id='y', ctx=load)
z = ast.Name(id='z', ctx=load)
mx = unit(x)
binop = lambda u, op, v: unit(ast.BinOp(left=u, op=op(), right=v))
and_y = lambda u: binop(u, ast.BitAnd, y)
or_z = lambda u: binop(u, ast.BitOr, z)
y_and = lambda v: binop(y, ast.BitAnd, v)
z_or = lambda v: binop(z, ast.BitOr, v)
mfuncs = [unit, lift(identity), and_y, or_z, y_and, z_or]
# left identity:
for mf in mfuncs:
ast_eq(bind(mx, mf), mf(x))
# right identity:
ast_eq(bind(mx, unit), mx)
# associativity:
for mf, mg in itertools.product(mfuncs, repeat=2):
ast_eq(
bind(bind(mx, mf), mg),
bind(mx, lambda v: bind(mf(v), mg))
)
def expand_call(node):
if is_name(node):
return collect_functor(unit(node)())
elif is_call(node):
return collect_functor(unit(copy.deepcopy(node)))
else:
raise TypeError('Name or Call node expected, not {}'.format(node))
def test_expression_operators():
"Test all Expression factory functions that are called as operators."
from hornet.expressions import unit, Num
from hornet.symbols import x, y
x_name = x.node
y_name = y.node
name = 'joe'
num = 123
items = [Num(1), Num(2), Num(3)]
pairs = (
[x[y], ast.Subscript(value=x_name, slice=ast.Index(y_name), ctx=load)],
[x(1, 2, 3),
ast.Call(
func=x_name,
args=items,
keywords=[],
starargs=None,
kwargs=None,
)],
)
for expr, node in pairs:
ast_eq(expr, unit(node))
pairs = (
[-x, ast.USub],
[+x, ast.UAdd],
[~x, ast.Invert],
)
for expr, op in pairs:
ast_eq(expr, unit(ast.UnaryOp(op(), x_name)))
pairs = (
[x ** y, ast.Pow],
[x * y, ast.Mult],
[x / y, ast.Div],
[x // y, ast.FloorDiv],
[x % y, ast.Mod],
[x + y, ast.Add],
[x - y, ast.Sub],
[x << y, ast.LShift],
[x >> y, ast.RShift],
[x & y, ast.BitAnd],
[x ^ y, ast.BitXor],
[x | y, ast.BitOr],
)
for expr, op in pairs:
ast_eq(expr, unit(ast.BinOp(x_name, op(), y_name)))
def test_expression_factories():
"Test all Expression factory functions that are called directly."
from hornet.expressions import (
unit, Name, Str, Bytes, Num, Tuple, List, Set, Wrapper, AstWrapper
)
class Callable:
def __call__(self):
pass
obj = object()
name = 'joe'
num = 123
keys = [Str('a'), Str('b'), Str('c')]
values = [Num(1), Num(2), Num(3)]
pairs = (
[Name(name), ast.Name(id=name, ctx=load)],
[Str(name), ast.Str(s=name)],
[Bytes(name), ast.Bytes(s=name)],
[Num(num), ast.Num(n=num)],
[Tuple(keys), ast.Tuple(elts=keys, ctx=load)],
[List(keys), ast.List(elts=keys, ctx=load)],
[Set(keys), ast.Set(elts=keys)],
[Wrapper(obj), AstWrapper(wrapped=obj)],
)
for expr, node in pairs:
ast_eq(expr, unit(node))
def expand_pushbacks(node):
if not node.elts:
return None
elif all(is_terminal(each) for each in node.elts):
elts = [collect_pushback(_C_(unit(each))) for each in node.elts]
return foldr(conjunction, elts)
else:
raise TypeError(
'Non-terminal in DCG pushback list found: {}'.format(node))
def expand_terminals(node, cont):
if not node.elts:
return cont(None)
elif all(is_terminal(each) for each in node.elts):
*elts, last = (
collect_terminal(_C_(unit(each))) for each in node.elts)
return foldr(conjunction, elts, cont(last))
else:
raise TypeError(
'Non-terminal in DCG terrminal list found: {}'.format(node))
def expand_body(node, cont):
if is_bitand(node):
def right_side(rightmost_of_left_side):
return conjunction(
rightmost_of_left_side,
expand_body(node.right, cont))
return expand_body(node.left, right_side)
elif is_list(node):
return expand_terminals(node, cont)
elif is_set(node):
assert len(node.elts) == 1
return cont(unit(node.elts[0]))
else:
return cont(expand_call(node))
def expand(root):
if not is_rshift(root):
return unit(root)
def expand_call(node):
if is_name(node):
return collect_functor(unit(node)())
elif is_call(node):
return collect_functor(unit(copy.deepcopy(node)))
else:
raise TypeError('Name or Call node expected, not {}'.format(node))
def expand_terminals(node, cont):
if not node.elts:
return cont(None)
elif all(is_terminal(each) for each in node.elts):
*elts, last = (
collect_terminal(_C_(unit(each))) for each in node.elts)
return foldr(conjunction, elts, cont(last))
else:
raise TypeError(
'Non-terminal in DCG terrminal list found: {}'.format(node))
def expand_pushbacks(node):
if not node.elts:
return None
elif all(is_terminal(each) for each in node.elts):
elts = [collect_pushback(_C_(unit(each))) for each in node.elts]
return foldr(conjunction, elts)
else:
raise TypeError(
'Non-terminal in DCG pushback list found: {}'.format(node))
def expand_body(node, cont):
if is_bitand(node):
def right_side(rightmost_of_left_side):
return conjunction(
rightmost_of_left_side,
expand_body(node.right, cont))
return expand_body(node.left, right_side)
elif is_list(node):
return expand_terminals(node, cont)
elif is_set(node):
assert len(node.elts) == 1
return cont(unit(node.elts[0]))
else:
return cont(expand_call(node))
def expand_clause(node):
head = node.left
body = node.right
if is_bitand(head):
def pushback(rightmost_of_body):
return conjunction(
rightmost_of_body,
expand_pushbacks(head.right))
return rule(
expand_call(head.left),
expand_body(body, pushback))
else:
return rule(
expand_call(head),
expand_body(body, identity))
from_left = []
from_right = collections.deque()
def collect_functor(call):
args = call.node.args
from_left.append(args.append)
from_left.append(args.append)
return call
def collect_terminal(call):
args = call.node.args
from_left.append(functools.partial(args.insert, -1))
from_left.append(args.append)
return call
def collect_pushback(call):
args = call.node.args
from_right.appendleft(functools.partial(args.insert, -2))
from_right.appendleft(args.append)
return call
clause = expand_clause(root)
pairs = splitpairs(rotate(itertools.chain(from_left, from_right)))
for (set_left, set_right), var in zip(pairs, numbered_vars('_')):
set_left(var)
set_right(var)
return clause