Guido van Rossum wrote:
...the syntax for "expression" doesn't allow a comma unless it's inside parentheses.
Perhaps a source of confusion might be that comma seems to act like a 'tuple join operator' when it is not inside parentheses. >>> x = 1, 2 >>> x (1, 2) And there is at least one point in the documentation where the comma is described as an operator: http://docs.python.org/ref/parenthesized.html "Note that tuples are not formed by the parentheses, but rather by use of the comma operator." As for the assert syntax, I would reuse the 'raise' keyword rather than 'else': assert_stmt ::= "assert" <expression> [ "raise" <expression> ] Which emphasizes that the expression is raised as an exception. Joel