def for_statement(self):
self.consume(TokenType.LEFT_PAREN, "Expect '(' after 'for'.")
# initializer = None
if self.match(TokenType.SEMICOLON):
initializer = None
elif self.match(TokenType.VAR):
initializer = self.var_declaration()
else:
initializer = self.expression_statement()
condition = None
if not self.check(TokenType.SEMICOLON):
condition = self.expression()
self.consume(TokenType.SEMICOLON, "Expect ';' after loop condition.")
increment = None
if not self.check(TokenType.RIGHT_PAREN):
increment = self.expression()
self.consume(TokenType.RIGHT_PAREN, "Expect ')' after for clauses.")
body = self.statement()
if increment is not None:
body = Stmt.Block([body, Stmt.Expression(increment)])
condition = SyntaxTree.Literal(
True) if condition is None else condition
body = Stmt.While(condition, body)
if initializer is not None:
body = Stmt.Block([initializer, body])
return body
def statement(self):
if self.match(TokenType.FOR):
return self.for_statement()
elif self.match(TokenType.IF):
return self.if_statement()
elif self.match(TokenType.PRINT):
return self.print_statement()
elif self.match(TokenType.RETURN):
return self.return_statement()
elif self.match(TokenType.WHILE):
return self.while_statement()
elif self.match(TokenType.LEFT_BRACE):
return Stmt.Block(self.block())
else:
return self.expression_statement()