Re: Perl 5 list assignment idiom

[rir]

On Mon, Mar 13, 2017 at 11:32:25AM -0700, Sean McAfee wrote:
> In Perl 5 ...

> 1 == (my ($script) = $page->find('//script'))
>   or die "Other than exactly one script element found";

> Can a similar expression that avoids an intermediate array variable be
> written in Perl 6?

This does that:

1 == ( my $script = {1,}() ).elems or die 'Not a 1 element list.';

Rob

Re: Perl 5 list assignment idiom

[Brock Wilcox]

The == operator coerces to Numeric, so like:

> sub one-thing { return ("hi",) }
sub one-thing () { #`(Sub|93867233982256) ... }
> one-thing.Numeric
1

(mentioned in https://docs.perl6.org/routine/$EQUALS_SIGN$EQUALS_SIGN)

I think my does indeed do some fancy precidenting with the assignment.

--Brock


On Mon, Mar 13, 2017 at 3:56 PM, Sean McAfee  wrote:

> sub one-thing { return ("hi",) }

Re: Perl 5 list assignment idiom

[Sean McAfee]

On Mon, Mar 13, 2017 at 12:37 PM, Will Coleda  wrote:

> Works the same in Perl 6, and you can avoid the parens. Using helper
> subs that return one or two item lists, here's some sample code:
>
> $ perl6
> > sub one-thing { return ("hi",) }
> sub one-thing () { #`(Sub|140454852043936) ... }
> > 1 == my $script = one-thing
> True
> > $script
> (hi)
>
>
But then:

> $script.WHAT
(List)

In the Perl 5 version, $script is assigned the single element of the
returned list.  In your code, it refers to the list itself.

(Also, wait: It looks like "=" has higher precedence than "=="?  Or does
the "my" affect the parsing somehow?)

Re: Perl 5 list assignment idiom

[Will Coleda]

Works the same in Perl 6, and you can avoid the parens. Using helper
subs that return one or two item lists, here's some sample code:

$ perl6
> sub one-thing { return ("hi",) }
sub one-thing () { #`(Sub|140454852043936) ... }
> 1 == my $script = one-thing
True
> $script
(hi)


> sub two-things { return  }
sub two-things () { #`(Sub|140454852044088) ... }
> 1 == my $bar = two-things
False
> $bar
(hi there)



On Mon, Mar 13, 2017 at 2:32 PM, Sean McAfee  wrote:
> In Perl 5, list assignment in scalar context evaluates to the number of list
> elements on the right-hand side.  That enables an idiom that I rather like:
>
> 1 == (my ($script) = $page->find('//script'))
>   or die "Other than exactly one script element found";
>
> Can a similar expression that avoids an intermediate array variable be
> written in Perl 6?
>



-- 
Will "Coke" Coleda

Re: perl 5?

[ToddAndMargo]

  
  
On 11/17/2016 05:34 AM, yary wrote:


  
Addning to Jan's answer,
PerlMonks is still a great place for answers on Perl5
  topics (and even some Perl6) http://perlmonks.org/




> I still do not have perl 6 support on rhel 7.2



Don't know how much of an "early
  adopter" you want to be- if that's an option, try building
  Rakudo from source, so you're not waiting on a package- http://rakudo.org/how-to-get-rakudo/#Installing-Rakudo-Star-Linux

  
-y

  
  

  


I do this with Wine-staging.  But it iwas a pain in the neck to
clear out all the stuff from the RPM.  

I wonder how much damage directly installing would cause when
the rpm finally comes out.  Different paths an all.  Mixed versions,
etc..
-- 
~~
Computers are like air conditioners.
They malfunction when you open windows
~~
  

Re: perl 5?

[ToddAndMargo]

  
  
On 11/16/2016 11:27 PM, Jan Ingvoldstad
  wrote:


  

  On Thu, Nov 17, 2016 at 8:08 AM,
ToddAndMargo 
wrote:
Hi All,
  
  Would you guys tolerate a perl 5 question every so often?
  

  
  
  
  Perl 5 questions that relate to Perl 6 would probably be on
  topic.


If what you want is help with Perl 5
  for Perl 5's sake, though, I humbly suggest that using one of
  the Perl 5 mailing lists, or IRC channels, may be more useful
  to you.


See here for more information:


https://lists.perl.org/



http://www.irc.perl.org/channels.html


  
  
  You may also find one of your local Perl communities
helpful, see here for more info about that:
  
  
  https://www.perl.org/community.html
  
  -- 
  Jan

  


And there is always perl monks, but their site 
required you hand code in html and has a really bizarre
thread mechanism.  But they can be very helpful at times too.

-- 
~~
Computers are like air conditioners.
They malfunction when you open windows
~~
  

Re: perl 5?

[Brandon Allbery]

On Thu, Nov 17, 2016 at 2:08 AM, ToddAndMargo  wrote:

> Would you guys tolerate a perl 5 question every so often?


Quite a few of the folks who work on Perl 6 don't know Perl 5, or at least
know it only incidentally.

-- 
brandon s allbery kf8nh   sine nomine associates
allber...@gmail.com  ballb...@sinenomine.net
unix, openafs, kerberos, infrastructure, xmonadhttp://sinenomine.net

Re: perl 5?

[yary]

Addning to Jan's answer,
PerlMonks is still a great place for answers on Perl5 topics (and even some
Perl6) http://perlmonks.org/


> I still do not have perl 6 support on rhel 7.2

Don't know how much of an "early adopter" you want to be- if that's
an option, try building Rakudo from source, so you're not waiting on a
package- http://rakudo.org/how-to-get-rakudo/#Installing-Rakudo-Star-Linux

-y

Re: perl 5?

[Jan Ingvoldstad]

On Thu, Nov 17, 2016 at 8:08 AM, ToddAndMargo  wrote:

> Hi All,
>
> Would you guys tolerate a perl 5 question every so often?
>
>
Perl 5 questions that relate to Perl 6 would probably be on topic.

If what you want is help with Perl 5 for Perl 5's sake, though, I humbly
suggest that using one of the Perl 5 mailing lists, or IRC channels, may be
more useful to you.

See here for more information:

https://lists.perl.org/

http://www.irc.perl.org/channels.html

You may also find one of your local Perl communities helpful, see here for
more info about that:

https://www.perl.org/community.html
-- 
Jan

Re: Perl 5's $0 vs. Perl 6's $*EXECUTABLE_NAME

[Paul Cochrane]

On 30 May 2015 3:00:25 pm GMT+02:00, Tom Browder tom.brow...@gmail.com wrote:
I finally found the Perl 6 version of Perl 5's $0 listed in:

  tablets.perl6.org/appendix-b-grouped.html#special-variables

as '$*EXECUTABLE_NAME', and I expected it to act the same as $0 in
Perl 6, but I have two problems with it:

1.  When used it yields 'perl6' regardless of the script's name (a
bug?).

$ cat t.pl
#!/usr/bin/env perl6
say $*EXECUTABLE_NAME;
$ chmod +x t.pl
$ ./t.pl
perl6

2.  It seems very ungainly to go from two characters to 17.  Couldn't
it be shortened a bit, say,

  '$*0' or '$*EXE_NAME' or '$*PROG' or something else?

Am I doing something wrong or do I have the wrong expectations?

$  perl6 --version
This is perl6 version 2015.03-48-g9746e88 built on MoarVM version
2015.03

Best regards,

-Tom

Hi Tom,

I believe what you are looking for is called $*PROGRAM_NAME. See also 
http://doc.perl6.org/language/variables#Special_Variables

Cheers,

Paul

Re: Perl 5's $0 vs. Perl 6's $*EXECUTABLE_NAME

[Tom Browder]

On Sat, May 30, 2015 at 8:30 AM, Tobias Leich em...@froggs.de wrote:
 Please also take a look at $*EXECUTABLE, $*PROGRAM and $*PROGRAM_NAME.

Tobias, I didn't find $*PROGRAM in the doc listed by Paul:

  http://doc.perl6.org/language/variables#Special_Variables

Also, the following were not in:

  http://tablets.perl6.org/appendix-a-index.html

that I could find.

  $*EXECUTABLE_NAME
  $*PROGRAM
  $*PROGRAM_NAME

From a Perl 6 newbie standpoint, it looks like there are too many docs
with overlapping purposes referenced on perl.org and which,
confusingly, have different pieces missing.  Except for the Synopses,
I'm not sure what document to go to for the definitive answer.  And,
as usual, I have no suggestions for an easy fix.

Thanks Paul and Tobias.

Best,

-Tom

Re: Perl 5's $0 vs. Perl 6's $*EXECUTABLE_NAME

[Paul Cochrane]

Hi Tom,

On Sat, May 30, 2015 at 09:03:17AM -0500, Tom Browder wrote:
 On Sat, May 30, 2015 at 8:30 AM, Tobias Leich em...@froggs.de wrote:
  Please also take a look at $*EXECUTABLE, $*PROGRAM and $*PROGRAM_NAME.
 
 Tobias, I didn't find $*PROGRAM in the doc listed by Paul:
 
   http://doc.perl6.org/language/variables#Special_Variables
 
 Also, the following were not in:
 
   http://tablets.perl6.org/appendix-a-index.html
 
 that I could find.
 
   $*EXECUTABLE_NAME
   $*PROGRAM
   $*PROGRAM_NAME

the docs at tablets.perl6.org aren't as up to date as those on
doc.perl6.org.  The doc.perl6.org docs are currently the reference work for
Perl6, however please note that they are very much a work in progress.

 From a Perl 6 newbie standpoint, it looks like there are too many docs
 with overlapping purposes referenced on perl.org and which,
 confusingly, have different pieces missing.  Except for the Synopses,
 I'm not sure what document to go to for the definitive answer.  And,
 as usual, I have no suggestions for an easy fix.

This I can understand.  We're doing our best to provide current and
accurate documentation.  Perl6 is a very large language, and thus gaps in
the documentation are to be expected; especially considering the volunteer
based nature of the project.

Thanks for pointing out the $*PROGRAM omission!  I've just added it to the
list of special variables and it should be available online within the next
10-15 minutes.

Kind regards,

Paul

Re: Perl 5's $0 vs. Perl 6's $*EXECUTABLE_NAME

[Tobias Leich]

Please also take a look at $*EXECUTABLE, $*PROGRAM and $*PROGRAM_NAME.

Am 30.05.2015 um 15:00 schrieb Tom Browder:
 I finally found the Perl 6 version of Perl 5's $0 listed in:

   tablets.perl6.org/appendix-b-grouped.html#special-variables

 as '$*EXECUTABLE_NAME', and I expected it to act the same as $0 in
 Perl 6, but I have two problems with it:

 1.  When used it yields 'perl6' regardless of the script's name (a bug?).

 $ cat t.pl
 #!/usr/bin/env perl6
 say $*EXECUTABLE_NAME;
 $ chmod +x t.pl
 $ ./t.pl
 perl6

 2.  It seems very ungainly to go from two characters to 17.  Couldn't
 it be shortened a bit, say,

   '$*0' or '$*EXE_NAME' or '$*PROG' or something else?

 Am I doing something wrong or do I have the wrong expectations?

 $  perl6 --version
 This is perl6 version 2015.03-48-g9746e88 built on MoarVM version 2015.03

 Best regards,

 -Tom

Re: Perl 5's $0 vs. Perl 6's $*EXECUTABLE_NAME

[Tom Browder]

On Sat, May 30, 2015 at 9:03 AM, Tom Browder tom.brow...@gmail.com wrote:
 On Sat, May 30, 2015 at 8:30 AM, Tobias Leich em...@froggs.de wrote:
 Please also take a look at $*EXECUTABLE, $*PROGRAM and $*PROGRAM_NAME.

 Tobias, I didn't find $*PROGRAM in the doc listed by Paul:

But it is the only one of the group I found in Synopsis 28 (Special names).

In S28 I did find the Perl 5 to Perl 6 translation table in which I
had overlooked $0 before.

-Tom

Re: Perl 5's $0 vs. Perl 6's $*EXECUTABLE_NAME

[Moritz Lenz]

Hi,

On 05/30/2015 04:36 PM, Paul Cochrane wrote:
 Thanks for pointing out the $*PROGRAM omission!  I've just added it to the
 list of special variables and it should be available online within the next
 10-15 minutes.

Minor nit pick: according to the last log on
http://doc.perl6.org/build-log/ building the docs alone takes ~17min;
the cron job runs every 5 minutes, so it's more likely 17-22min before
it becomes available :-)

And thanks for adding $*PROGRAM to the docs!

Cheers,
Moritz