Jeff, et al --
...and then Jeff 'japhy' Pinyan said...
%
% On Aug 17, David T-G said:
%
% > my $string = "Hello, #NAME_FIRST# #NAME_LAST# from #STATE#!" ;
...
% > my %xlate =
...
% >instance, in php, I would write something like
% >
% > $fields = array('#NAME_FIRST#','#NAME_LAST#','#STATE#') ;
% > $values = array('David','T-G','confusion') ;
% > $custom = preg_replace($fields,$values,$string) ;
% >
% >and be done.
%
% That's good of you to show how you'd do it in another language (yes, even
% if that language is PHP ;) ), because it clears up what you want to do.
Indeed. It was the most succinct way to explain it :-)
%
% There are two ways I see of doing it:
%
% $string =~ s{#(.*?)#}{
% if (exists $xlate{$1}) { $xlate{$1} } # if it's a valid key
% else { "#$1" } # if it's not in the hash, don't touch it
% }ge;
This looks interesting but I don't know that I follow it all the way.
The
s{#(.*?)#}
appears to look for my template strings. And so then the {}ge part looks
similar to a standard s///ge, so that's probably where it's doing the
real work.
I can somewhat follow the work (thanks for your patience, if you're
reading along with me). Based on a match like #NAME_FIRST# found in the
first line, we're going to look up the value pointed to by that hash key
in the xlate hash I built. I have to figure that
{ $xlate{$1} }
means to return that to the caller, even though it isn't return()ed or
print()ed or whatever.
So then we get to the really confusing part... AIUI we matched
#key#
but here we either say that we should spit
#key
back out or the #$1 means something that I don't get.
%
% The other way builds a regex of the keys in the hash first:
%
% my $keys = join '|', map quotemeta, keys %xlate;
% # quotemeta() make's sure any regex-characters in the keys are escaped
%
% $string =~ s/#($keys)#/$xlate{$1}/g;
Now this looks cool and is shorter, without necessarily being obfuscated.
That's excellent.
It's that funky map thing, though. I don't have much experience with
that :-)
Oh, I think I get it... We're only pulling the keys out of %xlate, and
we're quoting them to be safe. And you picked '|' for the join because
that's a regexp or, right? So my expr ends up being like
s/#(NAME_FIRST|NAME_LAST...)#/...
and the replacement is the bucket value of the key in the hash. Hey,
that's slick.
So why the map? Is that just a way to apply quotemeta to each key in the
hash?
%
% You'll notice for the second code we didn't need the 'e' modifier. That's
% because in the first chunk of code, the replacement was a function -- that
% is, it wasn't just a string, it was code that needed to be executed. The
Right.
% second time, though, we know $1 is a valid key in the hash, so there are
% no precautions needed.
Got that part, too.
Thanks again & HAND
:-D
--
David T-G * There is too much animal courage in
(play) [EMAIL PROTECTED] * society and not sufficient moral courage.
(work) [EMAIL PROTECTED] -- Mary Baker Eddy, "Science and Health"
http://justpickone.org/davidtg/ Shpx gur Pbzzhavpngvbaf Qrprapl Npg!
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