Re: WIP: hooking parser

Tom Lane wrote:
> Peter Eisentraut <peter_e@gmx.net> writes:
>> I think what you want here is some way to define a function that takes an 
>> arbitrary number of arguments of arbitrary type and let the function figure 
>> everything out.  I see no reason why this can't be a variant on CREATE 
>> FUNCTION, except that of course you need to figure out some API and function 
>> resolution details.
> 
> We've already got "variadic any" functions --- the problem is to tell
> the parser what the function's result type will be, given a particular
> parameter list.  I agree that hooking transformExpr is not exactly the
> most ideal way to attack that from a performance or complexity
> standpoint.

What is the defined return type logic for the decode() function anyway?  If you want the full CASE-like resolution
logic,it might be very hard 
 
to fit that into a general system.