Implicit current-index variable, scoped inside for-loops
Hey do you know what would be cool in perl 6
A special variable for when you do a for (@array) style loop
it would always have the index of the array
Discussed on #perl6: it's already quite easy in Perl 6 to loop with an
explicit index:
my @array = ;
for @array.kv -> $i, $val {
say "$i\t$val";
}
But maybe a variable that implicitly carries along the loop index
would be even snazzier?
for @array -> $val {
say "$.\t$val";
}
(Change "$." to whatever name would actually be appropriate in this
case. "$." contains the current line number for the last filehandle
accessed in Perl 5, and that's probably why I came to think of it
here.)
Questions:
- Is the itch big enough for this? The more I look at the first piece
of code, the more I'm thinking "that's not so bad, really". (Though
opinions differed on the IRC channel.) Is there a situation I'm not
thinking of where the first piece of code would suck, and the second
piece of code would rock? Or is this a case of oversugaring?
- I feel there's a trend of moving away from line-noise variables. I'd
hate to be one to propose adding a new one to the language. Is there a
better syntax than "$."?
- How would this work with non-array data? Specifically, what happens
with next, redo etc on a filehandle, for example?
See
for the #perl6 discussion.
--
masak
[svn:perl6-synopsis] r11527 - doc/trunk/design/syn
Author: audreyt
Date: Mon Aug 28 07:34:29 2006
New Revision: 11527
Modified:
doc/trunk/design/syn/S02.pod
Log:
* S02: minor grammar and syntax nit from p6l feedbacks.
Modified: doc/trunk/design/syn/S02.pod
==
--- doc/trunk/design/syn/S02.pod(original)
+++ doc/trunk/design/syn/S02.podMon Aug 28 07:34:29 2006
@@ -1396,13 +1396,17 @@
When used as a subscript it performs a slice equivalent to C<{'foo','bar'}>.
Elsewhere it is equivalent to a parenthesisized list of strings:
C<< ('foo','bar') >>. Since parentheses are generally reserved just for
-precedence grouping, they merely autointepolate in list context. Therefore
+precedence grouping, they merely autointerpolate in list context. Therefore
-@a = 1, < 2 3 >, 4;
+@a = 1, < x y >, 2;
-is equivalent to
+is equivalent to:
+
+@a = 1, ('x', 'y'), 2;
+
+which is the same as:
-@a = 1, 2, 3, 4;
+@a = 1, 'x', 'y', 2;
In scalar context, though, the implied parentheses are not removed, so
@@ -1410,12 +1414,12 @@
is equivalent to:
-$a = ('a','b');
+$a = ('a', 'b');
which, because the list is assigned to a scalar, is autopromoted into
an Array object:
-$a = ['a','b'];
+$a = ['a', 'b'];
Likewise, if bound to a scalar parameter, C<< >> will be
treated as a single list object, but if bound to a slurpy parameter,
Re: [svn:perl6-synopsis] r11504 - doc/trunk/design/syn
On 8/28/06, [EMAIL PROTECTED] <[EMAIL PROTECTED]> wrote:
+Elsewhere it is equivalent to a parenthesisized list of strings:
+C<< ('foo','bar') >>. Since parentheses are generally reserved just for
+precedence grouping, they merely autointepolate in list context. Therefore
+
+@a = 1, < 2 3 >, 4;
+
+is equivalent to
+
+@a = 1, 2, 3, 4;
Shouldn't this be
@a = 1, '2', '3', 4;
--
Markus Laire
Re: clarifying the spec for 'ref'
Richard Hainsworth skribis 2006-08-28 10:33 (+0400): > --- > | Class > A| > | > -- | > || Class B > | | > | > -- | > -- > Your mail program is wrapping this in a way that renders it unusable. Please make sure you use a monospaced font, and do not exceed the wrapping limit (typically 72 characters). > - > -| Class D | > | Class A | || > | > |---|-| > || > |-| > | --|- > | | > ---|-|-|- > | > | | | Class > B | > | > --| > |Class C | > I'm curious what this was supposed to look like. :) Juerd -- http://convolution.nl/maak_juerd_blij.html http://convolution.nl/make_juerd_happy.html http://convolution.nl/gajigu_juerd_n.html
Re: [svn:perl6-synopsis] r11504 - doc/trunk/design/syn
[EMAIL PROTECTED] writes:
> New Revision: 11504
>doc/trunk/design/syn/S02.pod
>
> +C<< ('foo','bar') >>. Since parentheses are generally reserved just for
> +precedence grouping, they merely autointepolate in list context. Therefore
Typo: "autointepolate".
Smylers
[svn:perl6-synopsis] r11509 - doc/trunk/design/syn
Author: audreyt
Date: Mon Aug 28 00:11:57 2006
New Revision: 11509
Modified:
doc/trunk/design/syn/S02.pod
Log:
* grammar nit, and clarify that it is the assign-to-scalar that Arrayify a list.
Modified: doc/trunk/design/syn/S02.pod
==
--- doc/trunk/design/syn/S02.pod(original)
+++ doc/trunk/design/syn/S02.podMon Aug 28 00:11:57 2006
@@ -1412,7 +1412,8 @@
$a = ('a','b');
-which, because the list is in scalar context, is autopromoted an Array object:
+which, because the list is assigned to a scalar, is autopromoted into
+an Array object:
$a = ['a','b'];
