def test_literal_expression(self):
# 5;
tokens = [
Token(TokenType.NUMBER, "5", 5.0, 0),
Token(TokenType.SEMICOLON, ";", None, 0),
Token(TokenType.EOF, "", None, 0),
]
parser = Parser(tokens)
statements = parser.parse()
self.assertEqual(len(statements), 1, "Expected 1 statement")
expression_statement = statements[0]
self.assertTrue(isinstance(expression_statement, Expression))
literal_expression = expression_statement.expression
self.assertTrue(isinstance(literal_expression, LiteralExpr))
self.assertEqual(literal_expression.value, 5)
def test_print_statement(self):
# print 20;
tokens = [
Token(TokenType.PRINT, "print", None, 0),
Token(TokenType.NUMBER, "20", 20.0, 0),
Token(TokenType.SEMICOLON, ";", None, 0),
Token(TokenType.EOF, "", None, 0),
]
parser = Parser(tokens)
statements = parser.parse()
self.assertEqual(len(statements), 1, "Expected 1 statement")
self.assertTrue(isinstance(statements[0], Print))
expression = statements[0].expression
self.assertTrue(isinstance(expression, LiteralExpr))
self.assertEqual(expression.value, 20)
def scan_tokens(self):
"""Parses all tokens until EOF for the provided source code string."""
while not self._is_at_end():
self.start = self.current
self.scan_token()
self.tokens.append(Token(TokenType.EOF, "", None, self.line))
return self.tokens
def test_binary_expression(self):
# 10 <= 20;
tokens = [
Token(TokenType.NUMBER, "10", 10.0, 0),
Token(TokenType.LESS_EQUAL, "<=", None, 0),
Token(TokenType.NUMBER, "20", 20.0, 0),
Token(TokenType.SEMICOLON, ";", None, 0),
Token(TokenType.EOF, "", None, 0),
]
parser = Parser(tokens)
statements = parser.parse()
self.assertEqual(len(statements), 1, "Expected 1 statement")
expression = statements[0].expression
self.assertTrue(isinstance(expression, BinaryExpr))
self.assertEqual(expression.left.value, 10)
self.assertEqual(expression.operator.token_type, TokenType.LESS_EQUAL)
self.assertEqual(expression.right.value, 20)
def scan_tokens(self):
while not self.is_at_end():
self.start = self.current
self.scan_token()
self.tokens.append(Token(TokenType.EOF, "", None, self.line))
return self.tokens
def add_token(self, type: TokenType, literal: object = None):
text = self.source[self.start:self.current]
self.tokens.append(Token(type, text, literal, self.line))
def _add_token(self, token_type, literal=None):
text = self.source[self.start:self.current]
self.tokens.append(Token(token_type, text, literal, self.line))
def setUp(self):
self.env = Environment()
self.x = Token(TokenType.VAR, "x", "x", 1)
self.undefined_var = Token(TokenType.VAR, "undefined_var", "undefined_var", 1)