def test_parse_atoms(self):
self.assertEqual(expr.parse('1'), True)
self.assertEqual(expr.parse('0'), False)
self.assertEqual(expr.parse('a'), expr.Variable(name='a'))
self.assertEqual(expr.parse('ab'), expr.Variable(name='ab'))
self.assertEqual(expr.parse('(a)'), expr.Variable(name='a'))
self.assertEqual(expr.parse(' 1'), True)
self.assertEqual(expr.parse('1 '), True)
def test_parse_exprs(self):
self.assertEqual(
expr.parse('a&1&0'),
expr.AndExpr(
exprs=frozenset([expr.Variable(name='a'), True, False])))
self.assertEqual(
expr.parse('a|1|0'),
expr.OrExpr(exprs=frozenset([expr.Variable(
name='a'), True, False])))
self.assertEqual(expr.parse('~a'),
expr.NotExpr(expr=expr.Variable(name='a')))
def primary(self) -> e.Expr:
if self.match(TokenType.FALSE):
return e.Literal(False)
if self.match(TokenType.TRUE):
return e.Literal(True)
if self.match(TokenType.NIL):
return e.Literal(None)
if self.match(TokenType.NUMBER, TokenType.STRING):
return e.Literal(self.previous().literal)
if self.match(TokenType.SUPER):
keyword: Token = self.previous()
self.consume(TokenType.DOT, "Expect '.' after 'super'.")
method: Token = self.consume(TokenType.IDENTIFIER,
"Expect superclass method name.")
return e.Super(keyword, method)
if self.match(TokenType.THIS):
return e.This(self.previous())
if self.match(TokenType.IDENTIFIER):
return e.Variable(self.previous())
if self.match(TokenType.LEFT_PAREN):
expr: e.Expr = self.expression()
self.consume(TokenType.RIGHT_PAREN, "Expect ')' after expression.")
return e.Grouping(expr)
raise self.error(self.peek(), "Expect expression.")
def _primary(self) -> ex.Expr:
if self._match(TokenType.FALSE):
return ex.Literal(False)
if self._match(TokenType.TRUE):
return ex.Literal(True)
if self._match(TokenType.NIL):
return ex.Literal(None)
if self._match(TokenType.NUMBER, TokenType.STRING):
return ex.Literal(self._previous.literal)
if self._match(TokenType.SUPER):
keyword = self._previous
self._consume(TokenType.DOT, "Expect a '.' after 'super'.")
method = self._consume(TokenType.IDENTIFIER,
'Expect superclass method name.')
return ex.Super(keyword, method)
if self._match(TokenType.THIS):
return ex.This(self._previous)
if self._match(TokenType.IDENTIFIER):
return ex.Variable(self._previous)
if self._match(TokenType.LEFT_PAREN):
expr = self._expression()
self._consume(TokenType.RIGHT_PAREN,
"Expect ')' after expression.")
return ex.Grouping(expr)
raise self._error(self._peek(), 'Expect expression.')
def crement(self):
isAdding = False
if self.peek(-1).type == TokenType.PLUS_PLUS:
isAdding = True
identifier = self.peek(-2)
if isAdding:
tok = TokenType.PLUS
else:
tok = TokenType.MINUS
val = 1
return Expr.Assignment(
Expr.Variable(identifier).name,
Expr.Binary(Expr.Variable(identifier),
Token(tok, None, None, None), Expr.Literal(val)))
def _class_declaration(self) -> st.Class:
name = self._consume(TokenType.IDENTIFIER, 'Expect class name.')
superclass = None
if self._match(TokenType.LESS):
self._consume(TokenType.IDENTIFIER, 'Expect superclass name.')
superclass = ex.Variable(self._previous)
self._consume(TokenType.LEFT_BRACE, "Expect '{' before class body.")
methods = []
while not self._check(TokenType.RIGHT_BRACE) and not self._is_at_end:
methods.append(self._function('method'))
self._consume(TokenType.RIGHT_BRACE, "Expect '}' after class body.")
return st.Class(name, superclass, methods)
def assignment(self):
left = self.ternary()
if self.match(TokenType.EQUAL):
equals = self.peek(-1)
value = self.assignment()
if isinstance(left, Expr.Variable):
return Expr.Assignment(left.name, value)
self.error(equals, "Invalid assignment target.")
elif self.match(TokenType.PLUS_EQUAL, TokenType.MINUS_EQUAL):
tok = TokenType.MINUS
if self.peek(-1).type == TokenType.PLUS_EQUAL:
tok = TokenType.PLUS
identifier = self.peek(-2)
val = self.expression()
return Expr.Assignment(
Expr.Variable(identifier).name,
Expr.Binary(Expr.Variable(identifier),
Token(tok, None, None, None), val))
return left
def classDeclaration(self) -> s.Stmt:
name: Token = self.consume(TokenType.IDENTIFIER, "Expect class name.")
superclass: Optional[e.Variable] = None
if self.match(TokenType.LESS):
self.consume(TokenType.IDENTIFIER, "Expect superclass name.")
superclass = e.Variable(self.previous())
self.consume(TokenType.LEFT_BRACE, "Expect '{' before class body.")
methods: List[s.Function] = []
while not self.check(TokenType.RIGHT_BRACE) and not self.isAtEnd():
methods.append(self.function("method"))
self.consume(TokenType.RIGHT_BRACE, "Expect '}' after class body.")
return s.Class(name, superclass, methods)
def primary(self):
if self.match(TokenType.FALSE):
return Expr.Literal(False)
if self.match(TokenType.TRUE):
return Expr.Literal(True)
if self.match(TokenType.NIL):
return Expr.Literal(None)
if self.match(TokenType.NUMBER, TokenType.STRING):
return Expr.Literal(self.peek(-1).literal)
if self.match(TokenType.LEFT_PAREN):
expr = self.expression()
self.consume(TokenType.RIGHT_PAREN, "Missing ')' after expression")
return Expr.Grouping(expr)
if self.match(TokenType.IDENTIFIER):
return Expr.Variable(self.peek(-1))
raise self.error(self.peek(), "Requires an expression")
def parse_atom(self):
token = self.get_token
if token.tag == Token.LPAREN:
e = self.parse_expr()
self.expect(Token.RPAREN)
return e
elif token.tag == Token.NUMBER:
return E.NumberLit(token.value)
elif token.tag == Token.ID:
return E.Variable(token.value)
elif token.tag == Token.LET:
var = self.get_token
assert (var.tag == Token.ID)
self.expect(Token.ASSIGN)
e1 = self.parse_expr()
self.expect(Token.IN)
e2 = self.parse_expr()
self.expect(Token.END)
return E.LetIn(var.value, e1, e2)
