Обсуждение: Proposal - Continue stmt for PL/pgSQL
Hello Statement CONTINUE isn't in PL/SQL too, I know it, but Oracle PL/SQL has statement GOTO. I don't need GOTO statement, but 'continue' can be very usefull for me. I have to do some ugly trick now. With little change, we can enhance stmt EXIT for behavior continue. After some work I can CREATE OR REPLACE FUNCTION lll() RETURNS void AS $$ DECLARE i integer = 0; BEGIN LOOP i = i + 1; CONTINUE WHEN i < 10; RAISE NOTICE '%', i; EXIT; END LOOP; BEGIN CONTINUE WHEN i = 10; RAISE NOTICE '---1---'; END; RAISE NOTICE '---2---'; FOR _i IN 1 .. 10 LOOP CONTINUE WHEN _i < 5; RAISE NOTICE '%', _i;END LOOP; END; $$ LANGUAGE plpgsql; select lll(); pokus=# NOTICE: 10 NOTICE: ---2--- NOTICE: 5 NOTICE: 6 NOTICE: 7 NOTICE: 8 NOTICE: 9 NOTICE: 10lll ----- (1 row) What do you think about it? It's broke PL/SQL compatibility, I know, but via last discussion I have opinion so Oracle compatibility isn't main objective PL/pgSQL. There is some less/bigger diferencess: SQLSTATE, EXCEPTION from my last proposal, atd. What do you think about it? Regards Pavel Stehule
Pavel, > Statement CONTINUE isn't in PL/SQL too, I know it, but Oracle PL/SQL > has statement GOTO. I don't need GOTO statement, but 'continue' can be > very usefull for me. I have to do some ugly trick now. With little change, > we can enhance stmt EXIT for behavior continue. Can you explain a little better what CONTINUE does that's different from EXIT? -- Josh Berkus Aglio Database Solutions San Francisco
On Thu, Jun 16, 2005 at 09:40:16 -0700, Josh Berkus <josh@agliodbs.com> wrote: > Pavel, > > > Statement CONTINUE isn't in PL/SQL too, I know it, but Oracle PL/SQL > > has statement GOTO. I don't need GOTO statement, but 'continue' can be > > very usefull for me. I have to do some ugly trick now. With little change, > > we can enhance stmt EXIT for behavior continue. > > Can you explain a little better what CONTINUE does that's different from EXIT? I suspect that CONTINUE is supposed to start the next iteration of the loop, while EXIT is supposed to terminate the loop.
Pavel Stehule <stehule@kix.fsv.cvut.cz> writes:
> BEGIN
> CONTINUE WHEN i = 10;
> RAISE NOTICE '---1---';
> END;
I find that really ugly and confusing. If we add a CONTINUE it's only
sensible to allow it inside a loop --- otherwise it's just a nonstandard
spelling of EXIT.
regards, tom lane
Pavel Stehule wrote: > >What do you think about it? It's broke PL/SQL compatibility, I know, but >via last discussion I have opinion so Oracle compatibility isn't main >objective PL/pgSQL. There is some less/bigger diferencess: SQLSTATE, >EXCEPTION from my last proposal, atd. > > > > Well, yes, but I don't think we should break compatibility arbitrarilly. I guess it could be argued that this is a missing feature in PL/SQL and its Ada parent - implementing GOTO just to handle this case seems unnecessary. I agree with Tom that it should only be allowed inside a loop. cheers andrew
As a near-daily PL/pgSQL developer, I similarly agree. -Jonah Andrew Dunstan wrote: > > > Pavel Stehule wrote: > >> >> What do you think about it? It's broke PL/SQL compatibility, I know, >> but via last discussion I have opinion so Oracle compatibility isn't >> main objective PL/pgSQL. There is some less/bigger diferencess: >> SQLSTATE, EXCEPTION from my last proposal, atd. >> >> >> >> > > Well, yes, but I don't think we should break compatibility > arbitrarilly. I guess it could be argued that this is a missing > feature in PL/SQL and its Ada parent - implementing GOTO just to > handle this case seems unnecessary. > > I agree with Tom that it should only be allowed inside a loop. > > cheers > > andrew > > ---------------------------(end of broadcast)--------------------------- > TIP 7: don't forget to increase your free space map settings
On Thu, 16 Jun 2005, Josh Berkus wrote: > Pavel, > > > Statement CONTINUE isn't in PL/SQL too, I know it, but Oracle PL/SQL > > has statement GOTO. I don't need GOTO statement, but 'continue' can be > > very usefull for me. I have to do some ugly trick now. With little change, > > we can enhance stmt EXIT for behavior continue. > > Can you explain a little better what CONTINUE does that's different from EXIT? > continue is equialent next iteration of cycle. exit break cycle. with block stmt? ~ break and continue are equal. Pavel
On Thu, 16 Jun 2005, Tom Lane wrote: > Pavel Stehule <stehule@kix.fsv.cvut.cz> writes: > > BEGIN > > CONTINUE WHEN i = 10; > > RAISE NOTICE '---1---'; > > END; > > I find that really ugly and confusing. If we add a CONTINUE it's only > sensible to allow it inside a loop --- otherwise it's just a nonstandard > spelling of EXIT. > I played too much :-). But, there is something wich can complicate implementation, if I disallow it inside block. for ... LOOP begin continue; end end loop; if I can use continue in begin and block I have easy rules for implementation. I have to first find any outside loop. But I think it's no really problem Pavel Stehule
> > Well, yes, but I don't think we should break compatibility > arbitrarilly. I guess it could be argued that this is a missing feature > in PL/SQL and its Ada parent - implementing GOTO just to handle this > case seems unnecessary. Yes. I din't use goto 5 years :-). Continue stmt is more cleaner and readable. now: FOR i IN 1 .. 100 LOOP continue := true WHILE continue LOOP ... EXIT; -- contine continue :=false; -- really exit END LOOP; END LOOP; with continue FOR i IN 1 .. 100 LOOP ... EXIT WHEN .. CONTINUE WHEN .. END LOOP; One argument for continue inside begin block - for discussion only. on loop exit means break iteration, continue new iteration. Continue and Exit are symmetric. I didn't know ADA haven't continue. In PL/pgSQL there isn't any problem implement continue stmt (wit any face), but goto stmt means relative big changes in source code. Pavel > > I agree with Tom that it should only be allowed inside a loop. > > cheers > > andrew > > ---------------------------(end of broadcast)--------------------------- > TIP 7: don't forget to increase your free space map settings >