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_as_ast(ast_source: Union[str, ast.AST]) -> ast.Lambda:
r'''Return an AST for a lambda function from several sources.
We are handed one of several things:
- An AST that is a lambda function
- An AST that is a pointer to a Module that wraps an AST
- Text that contains properly formatted ast code for a lambda function.
In all cases, return a lambda function as an AST starting from the AST top node,
and one where calls to Select, SelectMany, etc., have been replaced with proper
AST nodes.
Args:
ast_source: An AST or text string that represnets the lambda.
Returns:
An ast starting from the Lambda AST node.
'''
if isinstance(ast_source, str):
a = ast.parse(ast_source.strip())
return lambda_unwrap(replace_LINQ_operators().visit(a))
else:
return lambda_unwrap(ast_source)
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.
# TODO: figure out how to get pyright to not flag new_sequence_value as an error
rep = crep.cpp_sequence(new_sequence_value, seq.iterator_value())
select_ast.rep = rep
self._result = 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 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.
# Protect against sequence of sequences (LOVE type checkers, which caught this as a possibility)
w_val = seq.sequence_value()
if isinstance(w_val, crep.cpp_sequence):
raise BaseException(
"Internal error: don't know how to look at a sequence")
new_sequence_var = w_val.copy_with_new_scope(self._gc.current_scope())
node.rep = crep.cpp_sequence(new_sequence_var, seq.iterator_value())
self._result = node.rep
def test_parse_as_ast_lambda():
l = lambda_unwrap(ast.parse("lambda x: x + 1"))
r = parse_as_ast(l)
assert isinstance(r, ast.Lambda)