Passing estate to assign_simple_var()

Hi All,

I don't see any reason for passing estate variable to
assign_simple_var() in the current postgreSQL code. I think, it was
required earlier as we were updating param info in this function but,
now, we are not doing that here. So, shouldn't it be removed. Thoughts
?

I think, the ides of not updating param info inside this function got
changed as a part of the following git commit.

Rearrange execution of PARAM_EXTERN Params for plpgsql's
benefit.

This patch does three interrelated things:

* Create a new expression execution step type EEOP_PARAM_CALLBACK
and add the infrastructure needed for add-on modules to generate that.
As discussed, the best control mechanism for that seems to be to add
another hook function to ParamListInfo, which will be called by
ExecInitExpr if it's supplied and a PARAM_EXTERN Param is found.
For stand-alone expressions, we add a new entry point to allow the
ParamListInfo to be specified directly, since it can't be retrieved
from the parent plan node's EState.

--
With Regards,
Ashutosh Sharma
EnterpriseDB:http://www.enterprisedb.com