[Python-Dev] generalized resource alloc and de-alloc

[Greg Ewing]

Gareth McCaughan <gmccaughan@synaptics-uk.com>:

>     with LHS=EXPR:
>        BODY
> 
> is the same as
> 
>     TEMPNAME=EXPR
>     LHS=TEMPNAME.begin()
>     try:
>         BODY
>     finally:
>         TEMPNAME.end()

I like the simplicity of this as compared to the "under"
proposal.

Here's an even simpler version:

  with LHS = EXPR:
    BODY

is equivalent to

  LHS = EXPR
  try:
    BODY
  finally:
    del LHS

with TEMPNAME substituted for LHS if the latter is is omitted.

As a bonus, this would double as a means of introducing a
local name with restricted scope.

In fact, you could turn it around and describe it as a facility for
introducing local names with restricted scope, with one application of
using it as a resource-acquisition control structure.

Greg Ewing, Computer Science Dept, +--------------------------------------+
University of Canterbury,	   | A citizen of NewZealandCorp, a	  |
Christchurch, New Zealand	   | wholly-owned subsidiary of USA Inc.  |
greg@cosc.canterbury.ac.nz	   +--------------------------------------+