def check_BinaryOperator(node, env):
check(node.left, env)
check(node.right, env)
node.type = check_binop(node.left.type, node.operator, node.right.type)
if node.type is None and (node.left.type and node.right.type):
# if left and right have types then we are *not* in a cascading case
error(f'Invalid binop: {node.left.type} {node.operator} {node.right.type}')
def check_NamedLocation(node, env):
declaration = env.get(node.name)
if declaration is None:
error(f'Location {node} was not declared')
return # cannot do further checking
node.type = declaration.type
node.mutable = not isinstance(declaration, (Constant, Function))
def check_Function(node, env):
if node.name in env.maps[0]:
error(f'Duplicate definition of {node.name}.')
# and do NOT overwrite it ... originally defined function stays
else:
env[node.name] = node
local_env = env.new_child()
check(node.parameters, local_env)
check(node.statements, local_env)
def check_Assignment(node, env):
check(node.location, env)
check(node.expression, env)
# What I expect
if node.location.type != node.expression.type:
error(f'Type error on assignment: {node.location.type} != {node.expression.type}')
# Mutability: let's make assignment responsible for this
if not node.location.mutable: # Wishful Thinking Programming!
error(f"Cannot assign to immutable location: {node.location}")
def _checkVariableOrConst(node, env):
if node.value is not None:
check(node.value, env)
if node.type_specified_when_declared:
if node.value.type != node.type:
error(f'Variable defined as type {node.type} does not match {node.value.type}')
else:
# infer type from value
node.type = node.value.type
if node.name in env:
error(f'Duplicate definition of {node.name}')
env[node.name] = node
def check_FunctionCall(node, env):
# Check function arguments
check(node.args, env)
# Check that the function is defined
func = env.get(node.function_name)
if func is None:
error(f'Function {node.function_name} is not defined.')
# Check that the function is a function
if not isinstance(func, Function):
error(f'Cannot call {node.name} as a function')
return # ... and no further checking is possible
# Check that the function has all of the arguments that it needs
if len(func.parameters) != len(node.args):
error(f'Function is missing required arguments. Needs {func.parameters} got {node.args}')
# Check that the function parameter types match the supplied argument types
for n, (arg, param) in enumerate(zip(node.args, func.parameters), 1):
if param.type != arg.type:
error(f'Type error in argument {n}: {param.type} != {arg.type}')
node.type = func.return_type
def check_UnaryOperator(node, env):
check(node.operand, env)
node.type = check_unop(node.operator, node.operand.type)
if node.type is None:
error(f'Invalid unary operation: {node.operator}{node.operand}')
def check_While(node, env):
check(node.test, env)
if node.test.type != Bool.type:
error('If test did not evaluate to a Boolean!')
check(node.consequence, env.new_child())
def check_If(node, env):
check(node.test, env)
if node.test.type != Bool.type:
error('If test did not evaluate to a Boolean!')
check(node.consequence, env.new_child()) # Make a new scope (from ChainMap)
check(node.alternative, env.new_child())
def check_FunctionParameter(node, env):
if node.name in env.maps[0]:
error(f'Duplicate definition of {node.name}')
env[node.name] = node
