(I'm just studying the intricacies of Perl 6, so please correct me if
i say something stupid or if this has already been discussed before.)
I was looking for the Perl 6 equivalent of
"aaa" =~ /a{1,3}/
and finally found that it's
"aaa" ~~ /a**{1 .. 3}/
This looked rather weird, so i asked on IRC what is the mnemonic for it:
http://moritz.faui2k3.org/irclog/out.pl?channel=perl6;date=2007-06-29#id_l602
I got the reply that it is similar to exponentiation of variables in math:
a ** 5 == a * a * a * a * a == aaaaa
It makes sense after it is explained and i do like the rationalization
of the range as a list-like range, instead of the comma, but the **
syntax is rather ugly to my taste. Seeing that the ** quantifier is
not yet implemented anyway, I thought what could replace it, and the
best i could find was <1 .. 3>.
My rationale is this:
* It looks clean.
* It the chapter about Extensible metasyntax (<...>) in S05 most
paragraphs begin by "A leading X means yadda yadda", where X can be:
* whitespace
* alphabetic character (not alphanumeric!)
* ? $ :: @ % { & [ + - . ! ~~
... so numbers are not covered.
* As a side effect, * is a shortcut for <0 .. Inf>, + is a shortcut
for <1 .. Inf>, ? * is a shortcut for <0 .. 1>.
* The ? of non-greediness can come before the closing > - <1 .. 3 ?>
Any comments?
--
Amir Elisha Aharoni
my band: http://www.myspace.com/tzabari/
my blog: http://aharoni.wordpress.com/
