2011/3/2 Merlin Moncure <mmonc...@gmail.com> > On Wed, Mar 2, 2011 at 8:34 AM, Dmitriy Igrishin <dmit...@gmail.com> > wrote: > > 2011/3/2 Merlin Moncure <mmonc...@gmail.com> > >> On Tue, Mar 1, 2011 at 5:17 PM, Pavel Stehule <pavel.steh...@gmail.com> > >> wrote: > >> > Hello > >> > > >> > 2011/3/2 Pierre Racine <pierre.rac...@sbf.ulaval.ca>: > >> >> Hi, > >> >> > >> >> I would like to write a generic plpgsql function with a text > parameter > >> >> being a callback function name so that my general function can call > this > >> >> callback function. e.g.: > >> >> > >> >> CREATE OR REPLACE FUNCTION ST_MyCallbackFunction(y int) > >> >> RETURNS int AS $$ > >> >> DECLARE > >> >> BEGIN > >> >> RETURN someCalculationBasedOnY; > >> >> END; > >> >> $$ LANGUAGE 'plpgsql'; > >> >> > >> >> CREATE OR REPLACE FUNCTION ST_MyGeneralFunction(callback text) > >> >> RETURNS SETOF geomval AS $$ > >> >> DECLARE > >> >> x integer; > >> >> y integer; > >> >> BEGIN > >> >> y := somecalculation; > >> >> x := 'callback'(y); --This is what I need > >> > > >> > EXECUTE 'SELECT ' || callback || '($1)' USING y INTO x; > >> > > >> > there are no other way than EXECUTE > >> > > >> > attention - there is a sql injection risk > >> > >> another way if you are willing to write some C is to wrap and expose > >> OidFunctionCall1 so it takes oid of function you want to call. > > > > As always, Merlin shows the uncommon thinking! :-) > > Respect! > > Thank you, and I would like to be able to claim original invention of > this idea, however I cannot: it came from none other than Tom > Lane... > http://postgresql.1045698.n5.nabble.com/improvise-callbacks-in-plpgsql-td2052928.html > (for whom nary a day goes by that I am not thankful for his tireless > efforts). > Ahh, thanks to Tom Lane then ! And thank you for the link of interesting topic from past :-)
> merlin > -- // Dmitriy.
