PEP318 alternate syntax idea

[Jim Jewett]

Skip Montanaro <skip at pobox.com> wrote in message news:<mailman.305.1080075847.742.python-list at python.org>...
>     Jim> With decorators, the function definition itself is normal 
>     Jim> (and therefore should not be indented); it is the decorators
>     Jim> that run at an unexpected time.
 
>     Jim> using:
>     Jim>     decorator1
>     Jim>     decorator2
>     Jim>     decorator3
>     Jim> def a (args):
>     Jim>     pass

> Note that the undent at the end of the using: block also implies 
> that "we're done" with the block.  If I wrote

>     using:
>         decorator1
>         decorator2
>         decorator3
>     def a (args):
>         pass
>     def b (args):
>         pass
 
> would a and b both be decorated or just a?  What about if I wrote

Just a.  (If you want grouping, then you'll need a third header
clause to indicate that the using is done.)

if blocks (and for and while blocks, with the else) have the same issue.
The grammar production continues if and only if the next non-indented 
line is a valid continuation header clause.

    if test:
        stmt
        stmt
    elif:     # elif continues an if
        stmt
        stmt
    else:     # else continues an if
        stmt


    if test:
        stmt
    x = 5     # a binding does not continue an if; now it is over.

 
>     using:
>         decorator1
>         decorator2
>         decorator3
>     x = really_complex_default()
>     def a (arg1, arg2=x):
>         pass
 
> Would a be decorated or not?

Syntax error.  using: header clause not followed by def: or 
class: header clause.

The one part that feels awkward to me is that the optional 
clause (using:) comes first instead of second (elif:) or 
last (else:).

-jJ