Re: \if, \elseif, \else, \endif (was Re: PSQL commands:\quit_if, \quit_unless)
От | Fabien COELHO |
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Тема | Re: \if, \elseif, \else, \endif (was Re: PSQL commands:\quit_if, \quit_unless) |
Дата | |
Msg-id | alpine.DEB.2.20.1703300843020.2076@lancre обсуждение исходный текст |
Ответ на | Re: \if, \elseif, \else, \endif (was Re: PSQL commands: \quit_if, \quit_unless) (Tom Lane <tgl@sss.pgh.pa.us>) |
Ответы |
Re: \if, \elseif, \else, \endif (was Re: PSQL commands: \quit_if, \quit_unless)
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Список | pgsql-hackers |
Hello Tom, >> Patch applies cleanly. Make check ok. Feature still works! Idem for v30. > [...] Aside from cosmetic changes, I've made it behave reasonably for > cases where \if is used on portions of a query, for instance > > SELECT > \if :something > var1 > \else > var2 > \endif > FROM table; This is commendable, but I would not have bothered, although it is more cpp-like with it. A small issue I see is that I was planning to add such an if syntax to pgbench (well, at least if I succeed in getting boolean expressions and setting variables, which is just a maybe), but this kind of if in the middle of expression does not make much sense for a pgbench script where "if" must be evaluated at execution time, not parse time. > which as I mentioned a long time ago is something that people will > certainly expect to work. I would not have expected it to work, but indeed other people could. Sometimes I try something with pg and it does not work as I hoped. That is life. > I also cleaned up a lot of corner-case discrepancies between how much > text is consumed in active-branch and inactive-branch cases (OT_FILEPIPE > is a particularly nasty case in that regard :-() Indeed. > I plan to read this over again tomorrow and then push it, if there are > not objections/corrections. My small objection is that an eventual if in pgbench, with a separate parsing and execution, will not work in the middle of queries as this one. Do you think that such a discrepancy would be admissible. -- Fabien.
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