2009/4/20 Peter Eisentraut <pete...@gmx.net>: > On Sunday 19 April 2009 20:47:37 Pavel Stehule wrote: >> 2009/4/19 Peter Eisentraut <pete...@gmx.net>: >> > On Saturday 18 April 2009 18:09:00 Pavel Stehule wrote: >> >> There are lot of things, that should be done with current grammar only >> >> on transformation stage. Currently pg do it now. There are lot of >> >> pseudo functions, that are specially transformed: least, greatest, >> >> coalesce. After hooking we should do some similar work from outer >> >> libraries. >> > >> > There are surely other ways to accomplish this than an expression >> > transformation hook. Adding a property or two to the function definition >> > to do what you want could do it. >> >> should you describe it little bit more? > > The question we should be asking is, what is it that prevents us from > implementing least, greatest, and coalesce in user space now? And then design > a solution for that, if we wanted to pursue this. Instead of writing > transformation hooks and then force every problem to fit that solution. >
I don't believe so is possible to find other general solution. (or better I didn't find any other solution). Tom has true, transformationHook on expression is expensive. I thing, so hook on function should be simple and fast - not all transformation's should be simple defined via property - classic sample is "decode" like functions, it needs procedural code. regards Pavel Stehule -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
