Refactoring simplify_function (was: Caching constant stable expressions)

Hi list,

Per Tom's request, I split out this refactoring from my CacheExpr patch.

Basically I'm just centralizing the eval_const_expressions_mutator()
call on function arguments, from multiple different places to a single
location. Without this, it would be a lot harder to implement argument
caching logic in the CacheExpr patch.

The old call tree goes like:
case T_FuncExpr:
-> eval_const_expressions_mutator(args)
-> simplify_function
-> reorder_function_arguments
-> eval_const_expressions_mutator(args)
-> add_function_defaults
-> eval_const_expressions_mutator(args)

New call tree:
case T_FuncExpr:
-> simplify_function
-> simplify_copy_function_arguments
-> reorder_function_arguments
-> add_function_defaults
-> eval_const_expressions_mutator(args)

Assumptions being made:
* The code didn't depend on expanding existing arguments before adding defaults
* operator calls don't need to expand default arguments -- it's
currently impossible to CREATE OPERATOR with a function that has
unspecified arguments

Other changes:
* simplify_function no longer needs a 'bool has_named_args' argument
(it finds out itself).
* I added 'bool mutate_args' in its place, since some callers need to
mutate args beforehand.
* reorder_function_arguments no longer needs to keep track of which
default args were added.

Regards,
Marti

Marti Raudsepp <marti(at)juffo(dot)org> writes:
> Per Tom's request, I split out this refactoring from my CacheExpr patch.

> Basically I'm just centralizing the eval_const_expressions_mutator()
> call on function arguments, from multiple different places to a single
> location. Without this, it would be a lot harder to implement argument
> caching logic in the CacheExpr patch.

I've applied a slightly-modified version of this after reconciling it
with the protransform fixes. I assume you are going to submit a rebased
version of the main CacheExpr patch?

regards, tom lane

On Sat, Mar 24, 2012 at 01:17, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> I've applied a slightly-modified version of this after reconciling it
> with the protransform fixes.

Cool, thanks!

> I assume you are going to submit a rebased
> version of the main CacheExpr patch?

Yeah, I'm still working on addressing the comments from your last email.

Haven't had much time to work on it for the last 2 weeks, but I hope
to finish most of it this weekend.

Regards,
Marti

On Fri, Mar 23, 2012 at 7:41 PM, Marti Raudsepp <marti(at)juffo(dot)org> wrote:
> Yeah, I'm still working on addressing the comments from your last email.
>
> Haven't had much time to work on it for the last 2 weeks, but I hope
> to finish most of it this weekend.

Since the updated patch seems never to have been posted, I think this
one is dead for 9.2. I'll mark it Returned with Feedback.

--
Robert Haas
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