def test_relational_op_order(self):
'''Relational ops have lowest precedence: `3 * 5 + 3 == 18;`'''
given = iter([
Token('INTEGER', '3'),
Token('MUL', '*'),
Token('INTEGER', '5'),
Token('PLUS', '+'),
Token('INTEGER', '3'),
Token('EQUAL_EQUAL', '=='),
Token('INTEGER', '18'),
Token('SEMI', ';')
])
result = parser.parse(given)
expected = ast.Block([
ast.Statement(
ast.BinOp(
'==',
ast.BinOp(
'+',
ast.BinOp('*', ast.Integer(3), ast.Integer(5)),
ast.Integer(3)
),
ast.Integer(18)
)
)
])
assert result == expected
def test_mixed_expression(self):
'''An expression can have both numbers and ids:
`x * (y + 10);`'''
given = iter([
Token('ID', 'x'),
Token('MUL', '*'),
Token('LPAREN', '('),
Token('ID', 'y'),
Token('PLUS', '+'),
Token('INTEGER', '10'),
Token('RPAREN', ')'),
Token('SEMI', ';')
])
result = parser.parse(given)
expected = ast.Block([
ast.Statement(
ast.BinOp(
'*',
ast.ID('x'),
ast.BinOp('+', ast.ID('y'), ast.Integer(10))
)
)
])
assert result == expected
def test_parens(self):
'''Honors parenthesis: `(1 + 5) * 20;`'''
given = iter([
Token('LPAREN', '('),
Token('INTEGER', '1'),
Token('PLUS', '+'),
Token('INTEGER', '5'),
Token('RPAREN', ')'),
Token('MUL', '*'),
Token('INTEGER', '20'),
Token('SEMI', ';')
])
result = parser.parse(given)
expected = ast.Block([
ast.Statement(
ast.BinOp(
'*',
ast.BinOp('+', ast.Integer(1), ast.Integer(5)),
ast.Integer(20)
)
)
])
assert result == expected
def test_unary_op_expression(self):
'''Unary operations are supported: `(5 + -1) - !3;`'''
given = iter([
Token('LPAREN', '('),
Token('INTEGER', '5'),
Token('PLUS', '+'),
Token('MINUS', '-'),
Token('INTEGER', '1'),
Token('RPAREN', ')'),
Token('MINUS', '-'),
Token('BANG', '!'),
Token('INTEGER', '3'),
Token('SEMI', ';')
])
result = parser.parse(given)
expected = ast.Block([
ast.Statement(
ast.BinOp(
'-',
ast.BinOp(
'+',
ast.Integer(5),
ast.UnaryOp('-', ast.Integer(1))
),
ast.UnaryOp('!', ast.Integer(3))
)
)
])
assert result == expected
def test_simple_id(self):
'''IDs are treated as expressions: `x;`'''
given = iter([
Token('ID', 'x'),
Token('SEMI', ';')
])
result = parser.parse(given)
expected = ast.Block([
ast.Statement(
ast.ID('x')
)
])
assert result == expected
def test_add(self):
'''Can parse a simple addition: `1 + 1;`'''
given = iter([
Token('INTEGER', '1'),
Token('PLUS', '+'),
Token('INTEGER', '1'),
Token('SEMI', ';')
])
expected = ast.Block([
ast.Statement(ast.BinOp('+', ast.Integer(1), ast.Integer(1)))
])
result = parser.parse(given)
assert expected == result
def test_arrayref_expression(self):
'''Array reference is an expression: `arr[1];`'''
given = iter([
Token('ID', 'arr'),
Token('LBRACE', '['),
Token('INTEGER', '1'),
Token('RBRACE', ']'),
Token('SEMI', ';')
])
result = parser.parse(given)
expected = ast.Block([
ast.Statement(
ast.ArrayRef(ast.ID('arr'), ast.Integer(1))
)
])
assert result == expected
def test_float_expression(self):
'''Expression with floats and integers: `1.0 + 2;`'''
given = iter([
Token('FLOAT', '1.0'),
Token('PLUS', '+'),
Token('INTEGER', '2'),
Token('SEMI', ';')
])
result = parser.parse(given)
expected = ast.Block([
ast.Statement(
ast.BinOp(
'+',
ast.Float(1.0),
ast.Integer(2)
)
)
])
assert result == expected
def test_op_order(self):
'''Enforces the right op. precedence: `1 + 5 * 20;`'''
given = iter([
Token('INTEGER', '1'),
Token('PLUS', '+'),
Token('INTEGER', '5'),
Token('MUL', '*'),
Token('INTEGER', '20'),
Token('SEMI', ';')
])
expected = ast.Block([
ast.Statement(
ast.BinOp(
'+',
ast.Integer(1),
ast.BinOp('*', ast.Integer(5), ast.Integer(20))
)
)
])
result = parser.parse(given)
assert expected == result
def statement_expr(s):
return ast.Statement(s[0])
