Re: pg_execute_from_file review
Tom Lane <tgl@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Itagaki Takahiro <itagaki.takahiro@gmail.com>, Dimitri Fontaine <dimitri@2ndquadrant.fr>, Joshua Tolley <eggyknap@gmail.com>, pgsql-hackers@postgresql.org
Date: 2010-12-06T17:41:55Z
Lists: pgsql-hackers
Robert Haas <robertmhaas@gmail.com> writes: > On Sun, Dec 5, 2010 at 6:01 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote: >> Why is there a variadic replace() in this patch at all? It seems just >> about entirely unrelated to the stated purpose of the patch, as well >> as being of dubious usefulness. When would it be superior to >> replace(replace(orig, from1, to1), from2, to2), ... > An iterated replacement has different semantics from a simultaneous > replace - replacing N placeholders with values simultaneously means > you don't need to worry about the case where one of the replacement > strings contains something that looks like a placeholder. Good point, but what the patch implements is in fact iterated replacement ... or at least it looked that way in a quick once-over. > I actually > think a simultaneous replacement feature would be quite handy but I > make no comment on whether it belongs as part of this patch. My point is that the replacement stuff really really needs to be factored out of the string-execution stuff, precisely because the desired behavior is debatable. regards, tom lane