def try_to_find_var_and_set_it(self, var: Identifier, evaluated_value):
# Current scope should not be the outer scope
if self.parent_scope is None:
raise Exception
# We are allowed to change var in the global scope
if var.get_name() in self.symbol_table:
self.symbol_table[var.get_name()] = evaluated_value
return True
return False
def try_to_find_var_and_set_it(self, var: Identifier, evaluated_value):
# Check if var is in the current scope.
# If it's not check in the parent scope.
# Function stops calling itself when var is found and set
# or when it reaches global scope where it is stopped.
# Returns True if found and set var in current scope.
# Otherwise returns what parent returned.
if var.get_name() in self.symbol_table:
self.symbol_table[var.get_name()] = evaluated_value
return True
return self.parent_scope.try_to_find_var_and_set_it(
var, evaluated_value)
def get_var(self, var: Identifier):
# Loop through all parent scopes (including current scope)
# and return first matched variable or None if not found.
scope = self
while (value := scope.symbol_table.get(var.get_name(), None)) is None\
and scope.parent_scope is not None:
scope = scope.parent_scope
def set_var(self, var: Identifier, evaluated_value):
# To set variable means that
# the variable got assigned.
# First check if the variable exists
# in one of the parent scopes and if it does, reassign it.
# If it doesn't, add it to the symbol table of this scope.
if not self.try_to_find_var_and_set_it(var, evaluated_value):
self.symbol_table[var.get_name()] = evaluated_value