def check_iterator(self, iterator):
_, iter_symbol, iter_lineno = iterator
if iter_symbol in self.scope:
raise_error(
msg=
"trying to set previously declared variable '{0}' as iterator".
format(iter_symbol),
lineno=iter_lineno)
raise CompilerError()
def check_initialized(self, var):
if is_int(var):
_, symbol, lineno = var
if not self.initialized.get(symbol, False):
raise_error(
"Usage of uninitialized variable '{symbol}'".format(
symbol=symbol), lineno)
elif is_array(var):
# Cannot check int tab initialization
pass
def check_int(self, variable):
_, symbol, lineno = variable
if '#'.join([symbol, '0']) in self.scope:
raise_error(
msg="Usage of array variable '{symbol}' without specifing index"
.format(symbol=symbol),
lineno=lineno)
if symbol not in self.scope:
raise_error(
msg="Variable '{symbol}' not declared".format(symbol=symbol),
lineno=lineno)
def check_scope(self, operand):
if is_number(operand):
pass
elif is_int(operand):
if operand[1] not in self.scope:
raise_error(msg="Undeclared variable {}".format(operand[1]),
lineno=operand[2])
elif is_array(operand):
if is_number(operand[2]):
self.check_inttab(operand)
else:
raise CompilerError("Unexpected operand")
def check_inttab(self, variable):
_, symbol, index, lineno = variable
arr_start = '#'.join([symbol, '0'])
if arr_start not in self.scope:
raise_error("Usage of undeclared array {}".format(symbol), lineno)
if is_number(index):
self.check_inttab_index(variable)
elif is_int(index):
self.check_variable(index)
else:
raise CompilerError("Unexpected array index")
def check_assign(self, cmd):
_, target, expression = cmd
self.check_scope(target)
if is_int(target):
_, symbol, lineno = target
if symbol in self.iterators:
raise_error(
"Mutation of iterator '{symbol}'".format(symbol=symbol),
lineno)
elif is_array(target):
_, symbol, index, _ = target
symbol = '#'.join([symbol, str(index)])
else:
raise CompilerError("Unexpected target type")
self.check_expression(expression)
self.initialized[symbol] = True
def check_for_duplicate_declarations(self, declarations):
seen = []
arrays = {}
for kind, val, *details, lineno in declarations:
if val in seen:
raise_error(msg='double declaration of {}'.format(val),
lineno=lineno)
if kind == 'int[]':
[size] = details
seen.append(val + '#0')
if val in arrays.keys():
raise_error(
msg='double declaration of array {}'.format(val),
lineno=lineno)
arrays[val + '#0'] = size
else:
seen.append(val)
self.symbols = set(seen)
self.scope = set(seen)
self.arrays = arrays
def check_inttab_index(self, variable):
_, symbol, index, lineno = variable
if not 0 <= index <= self.arrays[symbol + '#0'] - 1:
raise_error("Array {} index out of range".format(symbol), lineno)