Over on use.perl, someone spotted what looks like a bug in the example
program which (if it *is* a bug) is fixed by using unary '*', but
that's not what I'm writing about here.
In the discussion of the yadda yadda yadda operator, Damian says that
... in this example, Err::BadData is *never*
Piers wrote:
> Over on use.perl, someone spotted what looks like a bug in the example
> program which (if it *is* a bug) is fixed by using unary '*', but
> that's not what I'm writing about here.
I'll admit I'm not sure whether it is a bug or not. I've asked Larry for
clarification and will post
from exegesis 4:
In Perl 6, the current topic -- whatever its name and however
you make it the topic -- is always aliased to $_.
and one of the examples is:
for @list -> $next {# iterate @list, aliasing each element to
# $next (and
Damian Conway <[EMAIL PROTECTED]> writes:
> Piers wrote:
>
>> Over on use.perl, someone spotted what looks like a bug in the example
>> program which (if it *is* a bug) is fixed by using unary '*', but
>> that's not what I'm writing about here.
>
> I'll admit I'm not sure whether it is a bug or n
> Good oh. BTW, (and apologies for repeating the question I asked
> elsewhere) are we going to see an updated Apocalypse 4 incorporating
> all the changes made to get E4 to work?
Probably not any time soon. Previous Apocalypses haven't been updated
when changes were made.
Eventually, of course,
Uri asked:
> but what if there are multiple bound variables like this example:
>
> for %phonebook.kv -> $name, $number {
> print "$name: $number\n"
> }
>
> is $_ aliased to either/both/neither of the two topics? are those now
> not topics but just aliased variabl
So, I've been looking at the stuff in the Apocalypses and Exegeses so
far and I think I've reached the point where I can have a crack at
using perl 6 to implement another programming language. Coming
(possibly) to a mailing list near you, Perl6::Scheme...
--
Piers
"It is a truth universally
Damian Conway <[EMAIL PROTECTED]> writes:
>> Good oh. BTW, (and apologies for repeating the question I asked
>> elsewhere) are we going to see an updated Apocalypse 4 incorporating
>> all the changes made to get E4 to work?
>
> Probably not any time soon. Previous Apocalypses haven't been
> updat
> > Eventually, of course, we'll have to go back and make eveything
> > copacetic, but at the moment I think most folks would rather have us
> > working on writing unwritten A's and E's, rather than rewriting
> > written ones. ;-)
>
> Point. Maybe someone will step up to plate and do Perl 6 so fa
> So, I've been looking at the stuff in the Apocalypses and Exegeses so
> far and I think I've reached the point where I can have a crack at
> using perl 6 to implement another programming language. Coming
> (possibly) to a mailing list near you, Perl6::Scheme...
"Be afraid. Be very afraid." ;-)
Just a thought, I assume that something like the following will be legal:
given $msg {
when Message::ACK {
$msg_store.fetch( $msg.acknowledged_msg ).set_state($msg);
}
when Message::SMS {
when .is_incoming { ... }
when .is_outgoin
Damian Conway <[EMAIL PROTECTED]> writes:
>> > Eventually, of course, we'll have to go back and make eveything
>> > copacetic, but at the moment I think most folks would rather have us
>> > working on writing unwritten A's and E's, rather than rewriting
>> > written ones. ;-)
>>
>> Point. Maybe
# Perl 5 code
for (my $i=0; 1; $i++) {
which would translate into Perl 6 as:
loop (my $i=0; 1; $i++) {
May I infer from this the return of loop-scoped variables (in
which the loop control variable is magically inser
Piers Cawley writes:
: Just a thought, I assume that something like the following will be legal:
:
: given $msg {
: when Message::ACK {
: $msg_store.fetch( $msg.acknowledged_msg ).set_state($msg);
: }
: when Message::SMS {
: when .is_incoming
Mark J. Reed writes:
:
: # Perl 5 code
: for (my $i=0; 1; $i++) {
:
: which would translate into Perl 6 as:
:
:
: loop (my $i=0; 1; $i++) {
:
:
: May I infer from this the return of loop-scoped variables (in
: which the loop control v
On 4/3/02 3:44 AM, Damian Conway wrote:
> Larry indicated to me that blockless declarations of methods and subs
> would be illegal.
What's the motivation for this? It seems to me that pre-declarations would
be just as nice (or nicer) as:
module Alpha;
package Beta;
method Gamma::del
At 07:57 AM 04-03-2002 -0800, Larry Wall wrote:
>Mark J. Reed writes:
>: loop (my $i=0; 1; $i++) {
>:
>
>No, the scope of $i stays outside, per the previous decision. If you
>want it inside you can always make $i an official formal parameter:
>
> for 0 .. Inf -> $i { ... }
>
>I t
John Siracusa:
# On 4/3/02 3:44 AM, Damian Conway wrote:
# > Larry indicated to me that blockless declarations of
# methods and subs
# > would be illegal.
#
# What's the motivation for this? It seems to me that
# pre-declarations would
# be just as nice (or nicer) as:
#
# module Alpha;
#
On 4/3/02 12:07 PM, Brent Dax wrote:
> John Siracusa:
> # On 4/3/02 3:44 AM, Damian Conway wrote:
> # > Larry indicated to me that blockless declarations of
> # methods and subs would be illegal.
> #
> # What's the motivation for this?
>
> I assume it's to support the Perl 5 blockless style.
Ah
Reading EX4 and seeing those "place-holder" variables made me wonder what
happens when someone (probably Damian ;) wants to use more than 26 of them.
Do the place-holder names scale up as if they're being automagically
incremented? (e.g. ..., y, z, aa, ab, ...)
-John
On Wed, Apr 03, 2002 at 12:41:13PM -0500, John Siracusa wrote:
> Reading EX4 and seeing those "place-holder" variables made me wonder what
> happens when someone (probably Damian ;) wants to use more than 26 of them.
> Do the place-holder names scale up as if they're being automagically
> incremen
On 4/3/02 12:49 PM, Jonathan Scott Duff wrote:
> On Wed, Apr 03, 2002 at 12:41:13PM -0500, John Siracusa wrote:
>> Reading EX4 and seeing those "place-holder" variables made me wonder what
>> happens when someone (probably Damian ;) wants to use more than 26 of them.
>> Do the place-holder names s
At 07:50 AM 4/3/2002 -0800, Larry Wall wrote:
>Piers Cawley writes:
>: Just a thought, I assume that something like the following will be legal:
>: Yeah, it's not good style; I should really be doing
>:
>: $msg.dispatch_to($self)
For some people (OO purists), switch statements are message dis
On Wed, Apr 03, 2002 at 12:53:33PM -0500, John Siracusa wrote:
> So it's the order that they appear that determines their binding? How would
> something like this (Perl 5 code) be represented:
>
> sub reverse_minus { $_[1] - $_[0] }
>
> I would have guessed it'd be:
>
> { $^b - $^a }
>
On Wed, Apr 03, 2002 at 12:41:13PM -0500, John Siracusa wrote:
> Reading EX4 and seeing those "place-holder" variables made me wonder what
> happens when someone (probably Damian ;) wants to use more than 26 of them.
> Do the place-holder names scale up as if they're being automagically
> incremen
Hi
I'm sure I'm missing something fairly fundamental, but could someone
shed more light on the example:
# reduce list three-at-a-time
$sum_of_powers = reduce { $^partial_sum + $^x ** $^y } 0, @xs_and_ys;
specifically what is being iterated over, what gets bound and what does
it return?
I tho
On Wed, Apr 03, 2002 at 12:41:13PM -0500, John Siracusa wrote:
> Reading EX4 and seeing those "place-holder" variables made me wonder what
Where is EX4? It's not at perl.org... so... ??
On Wed, Apr 03, 2002 at 12:19:13PM -0700, Luke Palmer wrote:
> On Wed, Apr 03, 2002 at 12:41:13PM -0500, John Siracusa wrote:
> > Reading EX4 and seeing those "place-holder" variables made me wonder what
>
> Where is EX4? It's not at perl.org... so... ??
Well, it's linked to from use.perl.org an
[EMAIL PROTECTED] writes:
: On Wed, Apr 03, 2002 at 12:41:13PM -0500, John Siracusa wrote:
: > Reading EX4 and seeing those "place-holder" variables made me wonder what
: > happens when someone (probably Damian ;) wants to use more than 26 of them.
: > Do the place-holder names scale up as if they
On Wed, Apr 03, 2002 at 11:27:10AM -0800, Larry Wall wrote:
> They are assumed to be declared in alphabetical order. Whoa! you say,
> that could get confusing. It surely can. But if you're doing
> something complicated enough that alphabetical order would be
> confusing, don't use this shorthan
Jonathan Scott Duff <[EMAIL PROTECTED]> writes:
> On Wed, Apr 03, 2002 at 11:27:10AM -0800, Larry Wall wrote:
>> They are assumed to be declared in alphabetical order. Whoa! you say,
>> that could get confusing. It surely can. But if you're doing
>> something complicated enough that alphabetic
Piers Cawley writes:
: Jonathan Scott Duff <[EMAIL PROTECTED]> writes:
:
: > On Wed, Apr 03, 2002 at 11:27:10AM -0800, Larry Wall wrote:
: >> They are assumed to be declared in alphabetical order. Whoa! you say,
: >> that could get confusing. It surely can. But if you're doing
: >> something c
Jonathan Scott Duff wrote:
>
> On Wed, Apr 03, 2002 at 12:41:13PM -0500, John Siracusa wrote:
> > Reading EX4 and seeing those "place-holder" variables made me wonder what
> > happens when someone (probably Damian ;) wants to use more than 26 of them.
> > Do the place-holder names scale up as if
Buddha Buck writes:
: At 07:57 AM 04-03-2002 -0800, Larry Wall wrote:
: >Mark J. Reed writes:
: >: loop (my $i=0; 1; $i++) {
: >:
: >
: >No, the scope of $i stays outside, per the previous decision. If you
: >want it inside you can always make $i an official formal parameter:
: >
: >
Piers Cawley wrote:
>
> Jonathan Scott Duff <[EMAIL PROTECTED]> writes:
>
> > On Wed, Apr 03, 2002 at 11:27:10AM -0800, Larry Wall wrote:
> >> They are assumed to be declared in alphabetical order. Whoa! you say,
> >> that could get confusing. It surely can. But if you're doing
> >> something
Andrew Wilson wrote:
> I'm sure I'm missing something fairly fundamental, but could someone
> shed more light on the example:
>
> # reduce list three-at-a-time
> $sum_of_powers = reduce { $^partial_sum + $^x ** $^y } 0, @xs_and_ys;
>
> specifically what is being iterated over, what gets bound
On Thu, Apr 04, 2002 at 09:37:19AM +1000, Damian Conway wrote:
Ah yes, that makes a lot of sense. Thank you.
Andrew
Mark J. Reed wrote:
>
> # Perl 5 code
> for (my $i=0; 1; $i++) {
>
> which would translate into Perl 6 as:
>
>
> loop (my $i=0; 1; $i++) {
>
>
> May I infer from this the return of loop-scoped variables (in
> which the loop control variab
On Wednesday 03 April 2002 18:24, Larry Wall wrote:
>
> Sure, just say
>
> { loop (my $i = intializer(); condition($i); $i = advance($i)) { ... }
}
>
> : Perhaps something like:
> :
> : initalizer() -> $i { LOOP: NEXT { $i = advance($i); redo LOOP if
> : condition($i);} ... }
> :
> : ex
On 4/3/02 6:44 PM, Damian Conway wrote:
> Larry has said very clearly that in Perl 6 there are no "magical" lexical
> scopes.
Shouldn't this be: "Larry has said very clearly that in Perl 6 there is only
one 'magical' lexical scope: sub() or ->"
-John
> Larry has said very clearly that in Perl 6 there are no "magical" lexical scopes.
> That is, variables declared in a C control aren't magically in the
> following block.
However, I don't agree with him. It may be more intuitive to newcomers,
but it is a common programming idiom that is used a
> {
> my @subs;
> loop (my $x = 0; $x < 10; $x++) {
> push @subs, { $^a + $x };
> }
> $x--;
> # ...
> }
>
> This certainly does *not* DWIM in the current thought. And the silence
> would be much more confusing than a simple syntax error the traditiona
So, does the new =~ commute now, except for regexps; i.e.
$a =~ $b
is the same as
$b =~ $a
unless one or both are regexps?
Additionally, can you chain statement modifiers?
do_this() if $a unless $b;
print for @mylist if $debug;
or less efficiently,
print if $debug for @mylist;
print "$
Luke Palmer writes:
: So, does the new =~ commute now, except for regexps; i.e.
:
: $a =~ $b
: is the same as
: $b =~ $a
:
: unless one or both are regexps?
I believe I marked which ones commute in A4.
: Additionally, can you chain statement modifiers?
:
: do_this() if $a unless $b;
: print f
[EMAIL PROTECTED] writes:
: On 4/3/02 6:44 PM, Damian Conway wrote:
: > Larry has said very clearly that in Perl 6 there are no "magical" lexical
: > scopes.
:
: Shouldn't this be: "Larry has said very clearly that in Perl 6 there is only
: one 'magical' lexical scope: sub() or ->"
It's specific
[EMAIL PROTECTED] writes:
: On Wednesday 03 April 2002 18:24, Larry Wall wrote:
: >
: > Sure, just say
: >
: > { loop (my $i = intializer(); condition($i); $i = advance($i)) { ... }
: }
: >
: > : Perhaps something like:
: > :
: > : initalizer() -> $i { LOOP: NEXT { $i = advance($i); redo
Larry wrote:
>
> [EMAIL PROTECTED] writes:
> : On 4/3/02 6:44 PM, Damian Conway wrote:
> : > Larry has said very clearly that in Perl 6 there are no "magical" lexical
> : > scopes.
> :
> : Shouldn't this be: "Larry has said very clearly that in Perl 6 there is only
> : one 'magical' lexical scope
Larry explained:
> : Umm. didn't you say bare blocks were going away?
>
> Rule #2 was invoked.
>
> The current thinking is that any bare block will never be interpreted
> as returning a closure. You have to use explicit C or C
> to return a closure.
Or the equivalent of a C, namely:
Damian Conway <[EMAIL PROTECTED]> writes:
> Larry explained:
>
>> : Umm. didn't you say bare blocks were going away?
>>
>> Rule #2 was invoked.
>>
>> The current thinking is that any bare block will never be interpreted
>> as returning a closure. You have to use explicit C or C
>> to retur
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