2017-01-09 1:10 GMT+01:00 Jim Nasby <jim.na...@bluetreble.com>: > On 1/8/17 12:03 AM, Pavel Stehule wrote: > >> BTW, I do wish you could change the label of the scope that >> arguments went into, so that you could use that label to refer >> to function parameters. If we allowed that it'd perhaps be the >> best of both worlds: you'd be guaranteed access to all auto >> variables and parameters, and that access wouldn't need to be >> tied to the function name (which can be both painful and error >> prone). >> >> >> We can talk about compiler directive. >> >> PRAGMA auto_variables_label(xxxx) -- require function scope only >> >> >> If we know a list of all auto variables, then it can be on function or >> block level - it can create aliases. >> > > Oh, the problem is that if you have an argument with the same name as an > auto variable you're in trouble. >
I didn't well explained my idea It is similar to your plpgsql scope. You are introducing the convention. I proposed a explicit specification. The result is similar. > > Probably the easiest thing is to have a scope that sits above the scope > containing the arguments, and then allow the user to rename both scopes if > so desired. So in effect you'd end up with > > <<plpgsql>> -- new scope > DECLARE > FOUND; > etc > BEGIN > <<function_name>> > DECLARE > argument_1; > argument_2; > BEGIN > -- User supplied block goes here, with optional label > END; > END; > It is similar to PRAGMA auto_variables_namespace(plpgsql); BEGIN ... END; Using PRAGMA is more verbose - it is useful for code audit, review - it is speaking "I will overwrite some auto variables here, and I need special namespace" plpgsql_check, maybe plpgsql self can raise warning if these variables are shadowed and some option/pragma is not used. Maybe current extra check does it already. > Alternatively, we could do... > > <<function_name>> > DECLARE > FOUND; > etc > BEGIN > DECLARE-- User's DECLARE > argument_1; > argomuent_2; > -- User supplied declare code > BEGIN -- User's BEGIN > .... > END > > That removes one level of nesting. It's probably better to go with the > first option though, since it's simpler. > You are forgot on function paramaters - somebody can use a function argument like FOUND, .. So auto variables should to be declared in most top namespace. Usually it is invisible for users - one, two more namespaces has zero cost for compilation and absolute zero impact for evaluation. > > In both cases, I'd really like the ability to rename those blocks. #pragma > would be fine for that. > > -- > Jim Nasby, Data Architect, Blue Treble Consulting, Austin TX > Experts in Analytics, Data Architecture and PostgreSQL > Data in Trouble? Get it in Treble! http://BlueTreble.com > 855-TREBLE2 (855-873-2532) >
