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On 12/18/06, Abigail <abigail@xxxxxxx.xx> wrote:
> On Mon, Dec 18, 2006 at 12:47:58PM +0100, demerphq wrote:
> > On 12/18/06, Abigail <abigail@xxxxxxx.xx> wrote:
> > >On Sun, Dec 17, 2006 at 11:07:50PM -0800, Yoz Grahame wrote:
> > >> On 12/17/06, Robert Rothenberg <robrwo@xxxxx.xxx> wrote:
> > >> >
> > >> >Bad comparison: traditional regexps are much easier to read than the
> > >ones
> > >> >used in contemporary programming languages.
> > >>
> > >> PCRE-style regexp in Javascript:
> > >> regexp = /(\d{1,3}\.){3}\d{1,3}/;
> > >>
> > >> Traditional POSIX regexp in C:
> > >> char regexp[] = "\\([:digit:]\{1,3\}\\.\\)\\{3\\}[:digit:]\\{1,3\\}";
> > >>
> > >> The second one is clearly the more horrific of the two hateful messes,
> > >> but I'll give you that it's *way* more fun to type if you just can't
> > >> get enough joyful bouncing on the backslash key.
> > >> (And traditional POSIX holds an even deeper hate - backslashes EITHER
> > >> switch a character from being a literal to a metacharacter, OR from a
> > >> metacharacter to a literal, depending on the character in question.
> > >> Consistency's for suckers, clearly.)
> > >
> > >
> > >Well, so does Perl, and so your PCRE example. The latter backslashes
> > >the d, turning the literal d into a metacharacter, and it backslashes
> > >the ., turning the metacharacter . into the literal .
> >
> > In Perl the rule is: If its an alpha-numeric char then escaping it
> > turns it into a meta pattern. If its non-alpha then escaping it turns
> > it into a literal. The latter rule is hard, and afaik applies to every
> > Perl. Hatefully tho perl will treat an unknown escape-alphanum
> > sequence as an unescaped char, not even warning.
>
>
> $ perl -wle '"q" =~ /\q/ or print "Ping"'
> Unrecognized escape \q passed through at -e line 1.
>
>
> Which to me seems that Perl treats an unknown escape-alphanum as an
> unescape char and it warns it did so.
Ah right. I forgot that the perl toker does the whining in that case.
That whole issue is hateful unto itself.
yves
--
perl -Mre=debug -e "/just|another|perl|hacker/"
There's stuff above here
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