Re: Nice Channel and thread example

[Elizabeth Mattijsen]

Fixed with https://github.com/rakudo/rakudo/commit/91543fe310 , thanks for the 
report!

> On 31 Oct 2017, at 00:32, Norman Gaywood  wrote:
> 
> Hmm, in developing this I was using an old perl6:
> 
> This is rakudo version 2015.11-554-g3b4964b built on MoarVM version 
> 2015.11-49-g27f15d9 implementing Perl v6.b.
> 
> I updated perl6 to the one that comes with Fedora:
> 
> This is Rakudo version 2017.08 built on MoarVM version 2017.08.1 implementing 
> Perl 6.c
> 
> Now when I run this program I get an exception when I do:
> 
> close $dir-channel;
> 
> Tried to get the result of a broken Promise
>   in block  at ./traverse-dir0.p6 line 7
> 
> Original exception:
> Cannot resolve caller close(Channel); none of these signatures match:
> (IO::Handle:D $fh)
>   in block  at ./traverse-dir0.p6 line 12
> 
> However, if I change the line 12 to:
> 
> $dir-channel.close;
> 
> The program does not throw and exception on this line and runs properly.
> 
> 
> 
> On 30 October 2017 at 16:58, Norman Gaywood  wrote:
> Looking at Andrew Shitov's new "Using Perl6" book and was playing around with 
> his "94. Parallel file processing" and came up with the following (I think 
> nice) example.
> 
> # There is a thread to populate $dir-channel by reading filenames in a 
> directory with dir()
> # and $N worker threads to read the filenames from the $dir-channel.
> 
> use v6;
> 
> sub MAIN( $dir = ".", :$N = 4 ) {
> 
> my $dir-channel = Channel.new();
> my $dir-read = start {
> $dir-channel.send( $_ ) for dir $dir;
> close $dir-channel;
> }
> 
> my @workers = (^$N).map: {
> start {
> while my $file = $dir-channel.receive() {
> say $file.path;
> }
> CATCH {
> when X::Channel::ReceiveOnClosed { .resume }
> }
> }
> }
> 
> await $dir-read, @workers;
> }
> 
> 
> -- 
> Norman Gaywood, Computer Systems Officer
> School of Science and Technology
> University of New England
> Armidale NSW 2351, Australia
> 
> ngayw...@une.edu.au  http://turing.une.edu.au/~ngaywood
> Phone: +61 (0)2 6773 2412  Mobile: +61 (0)4 7862 0062
> 
> Please avoid sending me Word or Power Point attachments.
> See http://www.gnu.org/philosophy/no-word-attachments.html
> 
> 
> 
> -- 
> Norman Gaywood, Computer Systems Officer
> School of Science and Technology
> University of New England
> Armidale NSW 2351, Australia
> 
> ngayw...@une.edu.au  http://turing.une.edu.au/~ngaywood
> Phone: +61 (0)2 6773 2412  Mobile: +61 (0)4 7862 0062
> 
> Please avoid sending me Word or Power Point attachments.
> See http://www.gnu.org/philosophy/no-word-attachments.html

Re: Nice Channel and thread example

[Norman Gaywood]

Hmm, in developing this I was using an old perl6:

This is rakudo version 2015.11-554-g3b4964b built on MoarVM version
2015.11-49-g27f15d9 implementing Perl v6.b.

I updated perl6 to the one that comes with Fedora:

This is Rakudo version 2017.08 built on MoarVM version 2017.08.1
implementing Perl 6.c

Now when I run this program I get an exception when I do:

close $dir-channel;

Tried to get the result of a broken Promise
  in block  at ./traverse-dir0.p6 line 7

Original exception:
Cannot resolve caller close(Channel); none of these signatures match:
(IO::Handle:D $fh)
  in block  at ./traverse-dir0.p6 line 12

However, if I change the line 12 to:

$dir-channel.close;

The program does not throw and exception on this line and runs properly.



On 30 October 2017 at 16:58, Norman Gaywood  wrote:

> Looking at Andrew Shitov's new "Using Perl6" book and was playing around
> with his "94. Parallel file processing" and came up with the following (I
> think nice) example.
>
> # There is a thread to populate $dir-channel by reading filenames in a
> directory with dir()
> # and $N worker threads to read the filenames from the $dir-channel.
>
> use v6;
>
> sub MAIN( $dir = ".", :$N = 4 ) {
>
> my $dir-channel = Channel.new();
> my $dir-read = start {
> $dir-channel.send( $_ ) for dir $dir;
> close $dir-channel;
> }
>
> my @workers = (^$N).map: {
> start {
> while my $file = $dir-channel.receive() {
> say $file.path;
> }
> CATCH {
> when X::Channel::ReceiveOnClosed { .resume }
> }
> }
> }
>
> await $dir-read, @workers;
> }
>
>
> --
> Norman Gaywood, Computer Systems Officer
> School of Science and Technology
> University of New England
> Armidale NSW 2351, Australia
>
> ngayw...@une.edu.au  http://turing.une.edu.au/~ngaywood
> Phone: +61 (0)2 6773 2412 <(02)%206773%202412>  Mobile: +61 (0)4 7862 0062
>
> Please avoid sending me Word or Power Point attachments.
> See http://www.gnu.org/philosophy/no-word-attachments.html
>



-- 
Norman Gaywood, Computer Systems Officer
School of Science and Technology
University of New England
Armidale NSW 2351, Australia

ngayw...@une.edu.au  http://turing.une.edu.au/~ngaywood
Phone: +61 (0)2 6773 2412  Mobile: +61 (0)4 7862 0062

Please avoid sending me Word or Power Point attachments.
See http://www.gnu.org/philosophy/no-word-attachments.html