def util_test_conv(f1, f2, f_expected):
a_1 = lambda_unwrap(ast.parse(f1))
a_2 = lambda_unwrap(ast.parse(f2))
a_expected = lambda_unwrap(ast.parse(f_expected))
s_1 = ast.dump(normalize_ast().start_visit(a_1))
s_2 = ast.dump(normalize_ast().start_visit(a_2))
s_expected = ast.dump(normalize_ast().start_visit(a_expected))
# Do the convolution
a_conv = convolute(a_1, a_2)
a_conv_reduced = simplify_chained_calls().visit(a_conv)
s_conv_reduced = ast.dump(normalize_ast().start_visit(a_conv_reduced))
s_1_after = ast.dump(normalize_ast().start_visit(a_1))
s_2_after = ast.dump(normalize_ast().start_visit(a_2))
# Make sure things match up with expected and nothing has changed.
assert s_1 == s_1_after
assert s_2 == s_2_after
assert s_conv_reduced == s_expected
def convolute(ast_g, ast_f):
'Return an AST that represents g(f(args))'
#TODO: fix up the ast.Calls to use lambda_call if possible
# Sanity checks. For example, g can have only one input argument (e.g. f's result)
if (not lambda_test(ast_g)) or (not lambda_test(ast_f)):
raise BaseException("Only lambdas in Selects!")
# Combine the lambdas into a single call by calling g with f as an argument
l_g = copy.deepcopy(lambda_unwrap(ast_g))
l_f = copy.deepcopy(lambda_unwrap(ast_f))
x = arg_name()
f_arg = ast.Name(x, ast.Load())
call_g = ast.Call(l_g, [ast.Call(l_f, [f_arg], [])], [])
# TODO: Rewrite with lambda_build
args = ast.arguments(args=[ast.arg(arg=x)])
call_g_lambda = ast.Lambda(args=args, body=call_g)
# Build a new call to nest the functions
return call_g_lambda
def parse_ast(ast_text):
'''Parse a string as a LINQ ast
NOTE: This must be called for every AST that the framework is converting from text.
ast_text: String containing a lambda function
returns:
ast: The python AST representing the function, with Select, SelectMany, etc., properly converted
to function call AST's.
'''
a = ast.parse(ast_text.strip())
return lambda_unwrap(replace_LINQ_operators().visit(a))
def visit_Select(self, select_ast):
'Transform the iterable from one form to another'
# Make sure we are in a loop
seq = self.as_sequence(select_ast.source)
# Simulate this as a "call"
selection = lambda_unwrap(select_ast.selection)
c = ast.Call(func=selection, args=[seq.sequence_value().as_ast()])
new_sequence_value = self.get_rep(c)
# We need to build a new sequence.
rep = crep.cpp_sequence(new_sequence_value, seq.iterator_value())
select_ast.rep = rep
self._result = rep
def visit_Where(self, node):
'Apply a filtering to the current loop.'
# Make sure we are in a loop
seq = self.as_sequence(node.source)
# Simulate the filtering call - we want the resulting value to test.
filter = lambda_unwrap(node.filter)
c = ast.Call(func=filter, args=[seq.sequence_value().as_ast()])
rep = self.get_rep(c)
# Create an if statement
self._gc.add_statement(statement.iftest(rep))
# Ok - new sequence. This the same as the old sequence, only the sequence value is updated.
new_sequence_var = seq.sequence_value().copy_with_new_scope(
self._gc.current_scope())
node.rep = crep.cpp_sequence(new_sequence_var, seq.iterator_value())
self._result = node.rep
def visit_SelectMany(self, node):
r'''
Apply the selection function to the base to generate a collection, and then
loop over that collection.
'''
# Make sure the source is around. We have to do this because code generation in this
# framework is lazy. And if the `selection` function does not use the source, and
# looking at that source might generate a loop, that loop won't be generated! Ops!
_ = self.as_sequence(node.source)
# We need to "call" the source with the function. So build up a new
# call, and then visit it.
c = ast.Call(func=lambda_unwrap(node.selection), args=[node.source])
# Get the collection, and then generate the loop over it.
# It could be that this comes back from something that is already iterating (like a Select statement),
# in which case we are already looping.
seq = self.as_sequence(c)
node.rep = seq
self._result = seq
def test_lambda_replace_simple_unwrapped():
t = lambda_unwrap(ast.parse("lambda b: b+1"))
b = ast.parse("2*b").body[0].value
expected = lambda_unwrap(ast.parse("lambda b: 2*b"))
assert ast.dump(expected) == ast.dump(lambda_body_replace(t, b))
def test_unwrap_bad_lambda():
try:
lambda_unwrap(ast.parse('x+1'))
assert False
except:
pass