I would suggest to throw a error, or at least a warning. This will FORCE people to program in the correct way.
I also thought that 'IF $1 THEN ...' should work ok but giving it a other thought it's indeed stuped to write that way (I'm from the C world...) Ries -----Oorspronkelijk bericht----- Van: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Tom Lane Verzonden: maandag 8 september 2003 17:41 Aan: [EMAIL PROTECTED]; [EMAIL PROTECTED] Onderwerp: [SQL] plpgsql doesn't coerce boolean expressions to boolean Following up this gripe http://archives.postgresql.org/pgsql-sql/2003-09/msg00044.php I've realized that plpgsql just assumes that the test expression of an IF, WHILE, or EXIT statement is a boolean expression. It doesn't take any measures to ensure this is the case or convert the value if it's not the case. This seems pretty bogus to me. However ... with the code as it stands, for pass-by-reference datatypes any nonnull value will appear TRUE, while for pass-by-value datatypes any nonzero value will appear TRUE. I fear that people may actually be depending on these behaviors, particularly the latter one which is pretty reasonable if you're accustomed to C. So while I'd like to throw an error if the argument isn't boolean, I'm afraid of breaking people's function definitions. Here are some possible responses, roughly in order of difficulty to implement: 1. Leave well enough alone (and perhaps document the behavior). 2. Throw an error if the expression doesn't return boolean. 3. Try to convert nonbooleans to boolean using plpgsql's usual method for cross-type coercion, ie run the type's output proc to get a string and feed it to bool's input proc. (This seems unlikely to avoid throwing an error in very many cases, but it'd be the most consistent with other parts of plpgsql.) 4. Use the parser's coerce_to_boolean procedure, so that nonbooleans will be accepted in exactly the same cases where they'd be accepted in a boolean-requiring SQL construct (such as CASE). (By default, none are, so this isn't really different from #2. But people could create casts to boolean to override this behavior in a controlled fashion.) Any opinions about what to do? regards, tom lane ---------------------------(end of broadcast)--------------------------- TIP 3: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly ---------------------------(end of broadcast)--------------------------- TIP 6: Have you searched our list archives? http://archives.postgresql.org
