def handle_call(name, actual_arglist):
'''
handle calls for both call statements and call expressions.
'''
# unpack the funval and type tuples
(FUNVAL, type, formal_arglist, body, context) = symtab.lookup_sym(name)
(FUNCTION_TYPE, ret_type, arg_types) = type
# set up the environment for static scoping and then execute the function
actual_val_args = eval_actual_args(actual_arglist)
save_symtab = symtab.get_config()
symtab.set_config(context)
symtab.push_scope(ret_type)
declare_formal_args(formal_arglist, actual_val_args)
# execute function
return_value = None
try:
walk(body)
except ReturnValue as val:
return_value = val.value
# NOTE: popping the function scope is not necessary because we
# are restoring the original symtab configuration
symtab.set_config(save_symtab)
return return_value
def id_exp(node):
(ID, name) = node
val = symtab.lookup_sym(name)
return val
def assign_stmt(node):
(ASSIGN, (ID, name), exp) = node
(t, v) = walk(exp)
(CONST, ts, (VALUE, vs)) = symtab.lookup_sym(name)
symtab.update_sym(name, ('CONST', ts, ('VALUE', coerce(ts, t)(v))))
return None
def get_stmt(node):
(GET, (ID, name)) = node
(CONST, type, value) = symtab.lookup_sym(name)
s = input("Value for " + name + '? ')
try:
# cannot use coerce here because that would be going
# down the type hierarchy which is not supported
if type[0] == 'STRING_TYPE':
new_value = s
elif type[0] == 'FLOAT_TYPE':
new_value = float(s)
elif type[0] == 'INTEGER_TYPE':
new_value = int(s)
else:
raise ValueError("input not supported for this type")
except ValueError:
raise ValueError("expected a {} value for {}".format(type[0], name))
symtab.update_sym(name, ('CONST', type, ('VALUE', new_value)))
return None
def id_exp(node):
(ID, name) = node
(CONST, type, (VALUE, value)) = symtab.lookup_sym(name)
return (type, value)