Re: [HACKERS] Syntax error and reserved keywords
Peter Eisentraut pete...@gmx.net writes: Is there a reason for us not to add an HINT: user is a reserved keyword or something like that, other than nobody having been interested in doing the work? If that were easily possible, we could just recognize 'user' as an identifier in this context and avoid the issue altogether. But it's not. Thanks, I guess I see the logic here. Regards, -- Dimitri Fontaine http://2ndQuadrant.fr PostgreSQL : Expertise, Formation et Support -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] Syntax error and reserved keywords
On 16.03.2012 14:50, Dimitri Fontaine wrote: Peter Eisentrautpete...@gmx.net writes: Is there a reason for us not to add an HINT: user is a reserved keyword or something like that, other than nobody having been interested in doing the work? If that were easily possible, we could just recognize 'user' as an identifier in this context and avoid the issue altogether. But it's not. Thanks, I guess I see the logic here. Accepting the keyword in such a context seems much harder to me than providing a hint. To accept the keyword, you'd need a lot of changes to the grammar, but for the hint, you just need some extra code in yyerror(). Mind you, if it's a hint, it doesn't need to be 100% accurate, so I think you could just always give the hint if you get a grammar error at a token that's a reserved keyword. Even if it was easy to accept the keywords when there's no ambiguity, I don't think we would want that. Currently, we can extend the syntax using existing keywords, knowing that we don't break existing applications, but that would no longer be true if reserved keywords were sometimes accepted as identifiers. For example, imagine that you had this in your application: CREATE TABLE foo (bar order); Order is a reserved keyword so that doesn't work currently, but we could accept it as an identifier in this context. But if we then decided to extend the syntax, for example to allow ORDER as a synonym for serial in CREATE TABLE clauses, that would stop working. We currently avoid introducing new reserved keywords, because that can break existing applications, but if we started to accept existing keywords as identifiers in some contexts, we would have to be more careful with even extending the use of existing keywords. However, I like the idea of a hint, so +1 for Dimitri's original suggestion. -- Heikki Linnakangas EnterpriseDB http://www.enterprisedb.com -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] Syntax error and reserved keywords
Heikki Linnakangas heikki.linnakan...@enterprisedb.com writes: Accepting the keyword in such a context seems much harder to me than providing a hint. To accept the keyword, you'd need a lot of changes to the grammar, but for the hint, you just need some extra code in yyerror(). Mind you, if it's a hint, it doesn't need to be 100% accurate, so I think you could just always give the hint if you get a grammar error at a token that's a reserved keyword. Unfortunately, while a useful hint doesn't have to be 100% right, it does have to be a great deal more than 0% right. And what you're suggesting here would be nearly all noise. For example, if I write SELECT ORDER BY x; it is not going to be helpful to be told that ORDER is a reserved word. It will soon become annoying for that hint to pop up in many contexts where it's completely inappropriate. If you could restrict it to only happen in contexts where the *only* expected token is an identifier, it might be of some use, but I'm doubtful that yyerror() has that much info. There is some stuff in the Bison manual about writing error productions, which I've never paid much attention to because it only seemed to be useful for resychronizing between statements. But maybe there's something there for this purpose. Even if it was easy to accept the keywords when there's no ambiguity, I don't think we would want that. Currently, we can extend the syntax using existing keywords, knowing that we don't break existing applications, but that would no longer be true if reserved keywords were sometimes accepted as identifiers. Good point. regards, tom lane -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
[HACKERS] Syntax error and reserved keywords
Hi, A colleague came to me to express his surprise about this quite simple use case: =# alter table toto add column user text; ERROR: syntax error at or near user LINE 1: alter table toto add column user text; Is there a reason for us not to add an HINT: user is a reserved keyword or something like that, other than nobody having been interested in doing the work? Regards, -- Dimitri Fontaine http://2ndQuadrant.fr PostgreSQL : Expertise, Formation et Support -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] Syntax error and reserved keywords
2012/3/14 Dimitri Fontaine dimi...@2ndquadrant.fr: Hi, A colleague came to me to express his surprise about this quite simple use case: =# alter table toto add column user text; ERROR: syntax error at or near user LINE 1: alter table toto add column user text; Is there a reason for us not to add an HINT: user is a reserved keyword or something like that, other than nobody having been interested in doing the work? Probably nobody did this work. I am thinking so on current code, this request is relatively simple implemented - and I agree so this can be really nice feature. Regards Pavel Regards, -- Dimitri Fontaine http://2ndQuadrant.fr PostgreSQL : Expertise, Formation et Support -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] Syntax error and reserved keywords
On 14-03-2012 10:58, Dimitri Fontaine wrote: Is there a reason for us not to add an HINT: user is a reserved keyword or something like that, other than nobody having been interested in doing the work? AFAIK, there is no such warning message in the code. If you're volunteering to do it, please cover all sql commands. -- Euler Taveira de Oliveira - Timbira http://www.timbira.com.br/ PostgreSQL: Consultoria, Desenvolvimento, Suporte 24x7 e Treinamento -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] Syntax error and reserved keywords
2012/3/14 Pavel Stehule pavel.steh...@gmail.com: 2012/3/14 Dimitri Fontaine dimi...@2ndquadrant.fr: Hi, A colleague came to me to express his surprise about this quite simple use case: =# alter table toto add column user text; ERROR: syntax error at or near user LINE 1: alter table toto add column user text; Is there a reason for us not to add an HINT: user is a reserved keyword or something like that, other than nobody having been interested in doing the work? Probably nobody did this work. I am thinking so on current code, this request is relatively simple implemented - and I agree so this can be really nice feature. but it is not too simple as I though this message coming from scanner_yyerror - and forwarding hint into this callback routine is not trivial - more - this message is used when word is reserved keyword and must not be and when word is just wrong reserved keyword. Regards Pavel Regards Pavel Regards, -- Dimitri Fontaine http://2ndQuadrant.fr PostgreSQL : Expertise, Formation et Support -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] Syntax error and reserved keywords
On ons, 2012-03-14 at 14:58 +0100, Dimitri Fontaine wrote: A colleague came to me to express his surprise about this quite simple use case: =# alter table toto add column user text; ERROR: syntax error at or near user LINE 1: alter table toto add column user text; Is there a reason for us not to add an HINT: user is a reserved keyword or something like that, other than nobody having been interested in doing the work? If that were easily possible, we could just recognize 'user' as an identifier in this context and avoid the issue altogether. But it's not. -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
