On Mittwoch, 2. Januar 2008, Thomas Bleher wrote: > * Markus Krötzsch <[EMAIL PROTECTED]> [2008-01-02 08:37]: > > On Sonntag, 30. Dezember 2007, Thomas Bleher wrote: > > > * Markus Krötzsch <[EMAIL PROTECTED]> [2007-12-30 22:10]: > > > > OK, my conclusion now was to support the following syntax: > > > > > > > > [[property% *subs?r*]] > > > > > > > > where ? and * represent _ and % in SQL. > > > > > > I think this is fine generally, but now you cannot query for a literal > > > * or ? anymore, AFAIK. > > > > I would not consider this to be a major issue, given that those > > characters are not too common in typical application strings, and given > > the fact that using "?" still queries for "some symbol" in that place -- > > it seems to be very unlikely that too strings differ only in one position > > where the query string has a "?". So in most cases it will have the same > > hits anyway (yes, there are some cases that could be problematic [1] ;). > > Agreed. > > > Anyway, I will leave this issue at rest until any user actually complains > > about this limitation. > > Here I have to respectfully disagree. > It seems unwise to wait until someone complains, when there is already a > patch resolving the issue.
OK, I give in. I will see to it as soon as I find the time.
-- Markus
> Why spend more time later on when the issue
> can just be fixed right now?
>
> OK, the regexes where not very readable, but it doesn't really make the
> code more complicated.
>
> FWIW, the regexes where so ugly only because backslashes have to be escaped
> twice for PHPs preg_replace (so a single \ becomes \\\\).
>
> If we used ! as an escape sequence instead of \, the regexes would look
> like this (untested):
>
> $value = str_replace(array('%', '_'), array('!%', '!_'), $value);
> $value = preg_replace('/(?<!!)((?:!!)*)\*/', '$1%', $value); // if there's
> an even number of \, change * to % $value =
> preg_replace('/(?<!!)((?:!!)*)\?/', '$1_', $value); // ditto for ? and _
> $value = preg_replace('/(?<!!)((?:!!)*)!\*/', '$1*', $value); // if there's
> an odd number, * was escaped and should stay as is; but the last \ is
> removed $value = preg_replace('/(?<!!)((?:!!)*)!\?/', '$1?', $value); //
> ditto for ?
>
> (?: ) is a subexpression for grouping, not capturing,
> (?<! ) is zero-width negative look-behind (i.e. we make sure that the
> character before our match is not !).
>
> Regards,
> Thomas
>
> > [1] http://de.wikipedia.org/wiki/Die_drei_%3F%3F%3F
> >
> > > Not a huge deal, but before, "a_b" searched for "a, followed by any
> > > char, followed by b", while "a\_b" searched for "exactly a_b".
> > >
> > > Properly escaping everything gets messy rather quickly, as \ can also
> > > be escaped to query for a literal \, so you need translations like:
> > >
> > > ? => _
> > > \? => ?
> > > \\? => \\_
> > > \\\? => \\?
> > >
> > > The following regular expressions work fine for me, but unfortunately
> > > they are quite ugly:
> > >
> > > $value = str_replace(array('%', '_'), array('\%', '\_'), $value); //
> > > escape % and _ $value = preg_replace('/(?<!\\\\)((?:\\\\\\\\)*)\*/',
> > > '$1%', $value); // if there's an even number of \, change * to % $value
> > > = preg_replace('/(?<!\\\\)((?:\\\\\\\\)*)\?/', '$1_', $value); // ditto
> > > for ? and _ $value = preg_replace('/(?<!\\\\)((?:\\\\\\\\)*)\\\\\*/',
> > > '$1*', $value); // if there's an odd number, * was escaped and should
> > > stay as is; but the last \ is removed $value =
> > > preg_replace('/(?<!\\\\)((?:\\\\\\\\)*)\\\\\?/', '$1?', $value); //
> > > ditto for ?
> > >
> > > I think these should be added to SMW, so all characters can be queried.
> > >
> > > Regards,
> > > Thomas
> >
> > --
> > Markus Krötzsch
> > Institut AIFB, Universät Karlsruhe (TH), 76128 Karlsruhe
> > phone +49 (0)721 608 7362 fax +49 (0)721 608 5998
> > [EMAIL PROTECTED] www http://korrekt.org
--
Markus Krötzsch
Institut AIFB, Universät Karlsruhe (TH), 76128 Karlsruhe
phone +49 (0)721 608 7362 fax +49 (0)721 608 5998
[EMAIL PROTECTED] www http://korrekt.org
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