[Python-Dev] ',' precedence in documentation]
jjb5 at cornell.edu
Mon Sep 15 17:14:10 CEST 2008
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
And there is at least one point in the documentation where the comma is
described as an operator:
"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
assert_stmt ::= "assert" <expression> [ "raise" <expression> ]
Which emphasizes that the expression is raised as an exception.
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