Re: generic builtin functions

Tom Lane wrote:

>Andrew Dunstan <andrew@dunslane.net> writes:
>  
>
>>What I want to have is some builtin functions that can be used as the 
>>input/output/cast/etc functions for each enum type.
>>    
>>
>
>The hard part of that is going to be figuring out how to get the
>information to the functions about which enum type they're being invoked
>for.  Output functions in particular are handed little except the data
>value itself.
>
>Possibly the internal representation of an enum could be 8 bytes: 4
>bytes for type OID and 4 more for value.  No doubt the mysql guys would
>rag on us for using too much disk space :-(.  But if you did that then
>the generics would just be anyenum and done.
>  
>


Eek! I would be prepared to go to quite a lot of trouble to avoid that.

My idea was to have the functions that need access to the text values 
look up fcinfo->flinfo->fn_oid and then use that to look up the type 
info. But that would mean we would need pg_proc entries for these 
functions for each enum, even if it's the same function underneath, 
wouldn't it?


>>I guess we could invent an anyenum pseudotype without actually exposing 
>>it via the grammar.
>>    
>>
>
>Why do you think you need to hide it?
>
>    
>  
>

Just desire not to clutter needlessly.

cheers

andrew