[Python-Dev] ',' precedence in documentation]

Guido van Rossum guido at python.org
Mon Sep 15 18:19:53 CEST 2008

On Mon, Sep 15, 2008 at 8:14 AM, Joel Bender <jjb5 at cornell.edu> wrote:
> 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.

Um, the question I was answering specifically asked *where is this in the docs*.

> 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."

Good sleuthing. Since you have found an inconsistency, now all the
docs are useless?

> 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.

But it is not -- it is the message passed to the exception constructor!

--Guido van Rossum (home page: http://www.python.org/~guido/)

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