2013/8/29 David E. Wheeler <da...@justatheory.com> > On Aug 29, 2013, at 1:11 PM, Pavel Stehule <pavel.steh...@gmail.com> > wrote: > > > I cannot to say what is good design for PL/pgSQL - only I feel so some > variant of RETURN statement is not good, because semantic is significantly > different. And I see a increasing inconsistency between a original ADA and > PL/pgSQL. > > So YIELD or implement PL/PSM. >
We can discussed about syntax later - now it is offtopic and it is too early - still we miss a procedures. > > > Sure, When I am thinking about PSM, I am thinking about T-SQL syntax, > but there is little bit simpler situation - there is a precedent in PSM > implementation in MySQL and some other new databases. > > PL/pgSQL is not PSM. > yes, I know it well - although some syntax is shared - CASE statements > > > so main problem is a impossibility to write > > > > BEGIN > > CALL fce() > > > > or > > > > BEGIN > > fce(); > > > > A workaround in Postgres is PERFORM - and I really has nothing again to > remove PERFORM for start of VOID functions! > > No reason SELECT could not work just a well. > No, originally, there was a target of compatibility with PL/SQL (more or less in some time), and PL/SQL disallow unbound SELECT. More - PL/SQL allow a direct procedure call - so some like PERFORM is useless there. > > > A unhelpful error message has zero relevant to topic - just almost all > in PL/pgSQL is SELECT. > > Well, it was an aside, but points out another problem with PERFORM: It > doesn't really exist. I gets replaced with SELECT internally, leading to > confusing error messages. Solution: Allow SELECT instead of PERFORM. > > > Do you would to remove a ":=" statement too? > > > > postgres=# do $$declare x int; begin x := notexisting(10); end; $$ ; > > ERROR: function notexisting(integer) does not exist > > LINE 1: SELECT notexisting(10) > > ^ > > HINT: No function matches the given name and argument types. You might > need to add explicit type casts. > > QUERY: SELECT notexisting(10) > > CONTEXT: PL/pgSQL function inline_code_block line 1 at assignment > > I agree it would be nice if it didn't report SELECT there, but at least > it's not *removing* anything from what you see in the source. > It was a little bit a irony. I am think now so all problems about PERFORM is based on porting PL/SQL environment (that was a classic simplified ADA) to PostgreSQL without procedures. So PERFORM was a designed for evaluation of something like procedures - but there was nothing in this time - a VOID functions are younger. Without PERFORM we didn't do this talk. Still I don't think so correct solution is enabling a unbound SELECTs, but correct is a fix a PERFORM and remove a necessity to use a PERFORM for call of VOID functions. Regards Pavel > > Best, > > David > > >
