def parse(self, precedence=0, required=True):
self.reader.skip_whitespace()
left_start = self.reader.offset
left = self.parse_left(required)
if left == None:
return None
self.add_node(left, left_start)
while True:
if self.hooks != None:
parsed = self.hooks.infix_prehook(left)
if parsed != None:
left = parsed
self.add_node(left, left_start)
continue
op = self.parse_operator()
if op == None or op.precedence <= precedence:
break
self.reader.expect_token(op.text)
op_text = self.config.aliases.get(
op.text) if op.text in self.config.aliases else op.text
if op.is_binary:
right = self.parse(op.precedence -
1 if op.is_right_assoc else op.precedence)
left = exprs.BinaryExpression(left, op_text, right)
elif op.is_postfix:
left = exprs.UnaryExpression(exprs.UNARY_TYPE.POSTFIX, op_text,
left)
elif op.text == "?":
when_true = self.parse()
self.reader.expect_token(":")
when_false = self.parse(op.precedence - 1)
left = exprs.ConditionalExpression(left, when_true, when_false)
elif op.text == "(":
args = self.parse_call_arguments()
left = exprs.UnresolvedCallExpression(left, [], args)
elif op.text == "[":
element_expr = self.parse()
self.reader.expect_token("]")
left = exprs.ElementAccessExpression(left, element_expr)
elif op.text in self.config.property_access_ops:
prop = self.reader.expect_identifier(
"expected identifier as property name")
left = exprs.PropertyAccessExpression(left, prop)
else:
self.reader.fail(
f'''parsing \'{op.text}\' is not yet implemented''')
self.add_node(left, left_start)
if isinstance(left, exprs.ParenthesizedExpression) and isinstance(
left.expression, exprs.Identifier):
expr = self.parse(0, False)
if expr != None:
return exprs.CastExpression(
astTypes.UnresolvedType(left.expression.text, []), expr)
return left
def parse_left(self, required=True):
result = self.hooks.unary_prehook() if self.hooks != None else None
if result != None:
return result
unary = self.reader.read_any_of(self.config.unary)
if unary != None:
right = self.parse(self.prefix_precedence)
return exprs.UnaryExpression(exprs.UNARY_TYPE.PREFIX, unary, right)
id = self.reader.read_identifier()
if id != None:
return exprs.Identifier(id)
num = self.reader.read_number()
if num != None:
return exprs.NumericLiteral(num)
str = self.reader.read_string()
if str != None:
return exprs.StringLiteral(str)
if self.reader.read_token("("):
expr = self.parse()
self.reader.expect_token(")")
return exprs.ParenthesizedExpression(expr)
if required:
self.reader.fail(
f'''unknown (literal / unary) token in expression''')
return None