Aaron Sherman writes:
: On Mon, 2002-04-22 at 21:53, Larry Wall wrote:
:
: > * Parens always capture.
: > * Braces are always closures.
: > * Square brackets are always character classes.
: > * Angle brackets are always metasyntax (along with backslash).
: >
: > So a first whack at the differences might be:
: [...]
: > space <sp> (or \h for "horizontal"?)
: > {n,m} <n,m>
: >
: > \t also <tab>
:
: I want to know how he does this!!
Could have something to do with the fact that I've been banging my head
against this for a couple of months already...
: We sit around scratching out heads
: looking for a syntax that fits and refines and he jumps in with
: something that redefines and simplifies. Larry is wasted on Perl. He
: needs to run for office ;-)
Agh, no! I'm okay at simplifying, but I'm terrible at oversimplifying.
: > \Lstring\E \L<string>
: > \Ustring\E \U<string>
:
: This one boggles me. Wouldn't that be something like:
:
: <tolower string> or <tolower>string</tolower> # ;-)
Well, <tolower:...> makes sense only if <> works in ordinary double quotes.
: Seriously, it seems that "\L<prior>" would be confusing.
Potentially, except that you almost never use it on anything but variable
interpoations. So \L<$foo> would be a better example. The confusing thing
is that $foo would not be assumed to be a regular expression, whereas it
would in bare <$foo> (at least in a regex).
: > \Q$var\E $var always assumed literal, so $1 is literal
:backref
: > $var <$var> assumed to be regex
:
: Very nice. I can get behind this, and a lot of people will thank you who
: have to maintain code.
Well, almost anything is an improvement over the current syntax.
: > =~ $re =~ /<$re>/ ouch?
:
: If $re is a regexp, wouldn't "$str =~ $re" turn into "$re.match($str)"?
: Perhaps "$re.m $str" which is no more typing and pretty clear to me.
Sure, but I was illustrating the situation of a non-qr string being
forced to be a regex.
: > Obviously the <word> and <word:...> syntaxes will be user extensible.
: > We have to be able to support full grammars. I consider it a feature
: > that <foo> looks like a non-terminal in standard BNF notation. I do
: > not consider it a misfeature that <foo> resembles an HTML or XML tag,
: > since most of those languages need to be matched with a fancy rule
: > named <tag> anyway.
:
: It's too bad that </tag> would be messy with standard Perl //-enclosed
: regexes, as it would be a nice way to pass parameters to user-defined
: tags. It would also allow XML-like propagation of results:
:
: <foo>x<bar>y</bar>z</foo>
Gee, maybe we could make a way for people to use alternate dilimiters
like they've always done with s///. :-)
Larry
