Re: Is this a bug?

[Aaron Sherman]

Thank you. Silly me, thinking "this is so simple I don't need to run it
through the command-line to test it." :-)

Anway, yeah,

 say $_ for reverse lines



Aaron Sherman, M.:
P: 617-440-4332 Google Talk, Email and Google Plus: a...@ajs.com
Toolsmith, developer, gamer and life-long student.


On Mon, Sep 19, 2016 at 10:10 AM, Timo Paulssen  wrote:

> On 19/09/16 16:02, Aaron Sherman wrote:
> > I'm guessing that what you meant was "say as a function was what I >
> meant to use there." In which case: > > say for reverse lines > > or > >
> for reverse lines { say } > > These are both valid ways of asking for each
> element of the iterable > thing returned from lines to be printed with a
> newline.
> Watch out, this needs to read say $_ otherwise you would get an error
> message:
>
> Unsupported use of bare "say"; in Perl 6 please use .say if you meant $_,
> or use an explicit invocant or argument, or use  to refer to the
> function as a noun
>
>

Re: Is this a bug?

[Parrot Raiser]

It may make it clearer if I explain the broader objective. I'm trying
to learn P6 thoroughly by developing training courses to teach it from
scratch. (Fans of Gerald Weinberg may recognise the idea.) Obviously,
while doing so, I want to explore pathological cases, both to clarify
the concepts and to anticipate the mistakes that students might make.
Sometimes, it's necessary to do so to resolve ambiguities in whatever
sources are available.

The language is far too deep and complex to absorb in one pass, and
contains a great deal which is of interest to advanced system software
developers, but not to someone who just wants to do some simple
processing or file manipulation. My aim is to develop a series of
successively deeper courses, each of which will be complete within
itself. The first level is procedural. O-O is the next.

Topics should proceed logically from the basics, each building on the
previous, without having to drag in extraneous topics or diversions.
(Examples should not require forward references or bouncing around in
the text.) That's why I don't want to introduce .say at this stage, if
I can help it.

On 9/18/16, Trey Harris  wrote:
> On Sun, Sep 18, 2016 at 16:49 Parrot Raiser <1parr...@gmail.com> wrote:
>
> say { $_ } was the correct thing to use there. (I'm trying to avoid
>> any mention of O-O for the moment.)
>>
> “Trying to avoid any mention of O-O” seems like a Perl 6 obfuscation or
> golf constraint, not a desirable development or learning goal. Perl 6
> doesn’t *force* you to write programs in an object-oriented style; you can
> do it in functional or procedural or whatever style suits you. But you’re
> going to have a bad time if you try to deny Perl 6’s fully OO nature. This
> is in stark contrast to Perl 5, where OO was bolted on, and you could say
> that the non-OO core was more “real” than the object-oriented sugar found
> in modules you had to use.
>
> Writing something like say($_) for reverse lines — which is what I think is
> closest to what you wanted — isn’t any more or less “object-oriented” than
> the more idiomatic .say for reverse lines;. In Perl 5, some rather
> byzantine rules governed the use of the implicit $_; almost all of the
> convenience afforded by those rules can be gained through the use of
> topicalized objects, so the byzantine rules are gone — but the convenience
> is gone too unless you’re willing to use the topic in the .foo style.
>
> I think perhaps you see a dot, and dot signifies OO, so the .say... version
> might *look* more OO than the say(... version in some sense, but that’s
> pretty much cosmetic. You’re *using* some objects by interacting with the
> Perl 6 core either way. It’s your choice not to write your logic in an OO
> style, but you can’t prevent OO from happening during execution.
>
> (This really isn’t some half-hearted attempt to force you into OO through
> the backdoor; you really can skip OO for all *your* logic. You just can’t
> pretend you’re not using an object-oriented language when you have to touch
> code you’re not in control of, whether an OO library or the Perl 6 core.
> But pretty much the entirety of what you need to know about OO if you
> choose to do that is various syntax and some desiderata about the calling
> semantics.)
>
> say {} was a "what happens if I do this" exercise.
>>
>> What is this  -> ;; $_? is raw { #`(Block|170303864) … } output?
>>
>> On 9/18/16, Brent Laabs  wrote:
>> > Remember you can call a block with parentheses:
>> >
>> >> say { 11 + 31 };
>> > -> ;; $_? is raw { #`(Block|140268472711224) ... }
>> >> say { 11 + 31 }();
>> > 42
>> >
>> >
>> > On Sun, Sep 18, 2016 at 12:58 PM, Elizabeth Mattijsen 
>> > wrote:
>> >
>> >> I think you want:
>> >>
>> >>   .say for reverse lines;
>> >>
>> >> not sure what you are trying to achieve otherwise, but:
>> >>
>> >>say { }
>> >>
>> >> producing something like
>> >>
>> >>-> ;; $_? is raw { #`(Block|170303864) … }
>> >>
>> >> feels entirely correct to me.   :-)
>> >>
>> >>
>> >> Liz
>> >>
>> >> > On 18 Sep 2016, at 21:52, Parrot Raiser <1parr...@gmail.com> wrote:
>> >> >
>> >> > This code:
>> >> > 1 #! /home/guru/bin/perl6
>> >> > 2
>> >> > 3 # Ask for some lines and output them in reverse
>> >> > 4 # Work out the appropriate EOF symbol for the OS
>> >> > 5
>> >> > 6 my $EOF = "CTRL-" ~ ($*DISTRO.is-win ?? "Z" !! "D");
>> >> > 7
>> >> > 8 say "Please enter some lines and end them with $EOF";
>> >> > 9
>> >> > 10 say { for reverse lines() {} };
>> >> > 11
>> >> > 12 # End
>> >> > produces this:
>> >> > Please enter some lines and end them with CTRL-D# obviously from
>> >> line 8
>> >> > -> ;; $_? is raw { #`(Block|170303864) ... }#
>> >> > but
>> >> this?
>> >>
>> >>
>> >
>>
> ​
>

Re: Is this a bug?

[Timo Paulssen]

On 19/09/16 16:02, Aaron Sherman wrote:
> I'm guessing that what you meant was "say as a function was what I > meant to 
> use there." In which case: > > say for reverse lines > > or
> > for reverse lines { say } > > These are both valid ways of asking
for each element of the iterable > thing returned from lines to be
printed with a newline.
Watch out, this needs to read say $_ otherwise you would get an error
message:

Unsupported use of bare "say"; in Perl 6 please use .say if you meant
$_, or use an explicit invocant or argument, or use  to refer to the
function as a noun

Re: Is this a bug?

[Aaron Sherman]

I'm guessing that what you meant was "say as a function was what I meant to
use there." In which case:

say for reverse lines

or

for reverse lines { say }

These are both valid ways of asking for each element of the iterable thing
returned from lines to be printed with a newline.

But remember that any {} around code creates a Block in Perl 6, and a Block
is a first-class object. If you ask say to print a Block, it will quite
happily try to do that.




Aaron Sherman, M.:
P: 617-440-4332 Google Talk, Email and Google Plus: a...@ajs.com
Toolsmith, developer, gamer and life-long student.


On Sun, Sep 18, 2016 at 4:49 PM, Parrot Raiser <1parr...@gmail.com> wrote:

> say { $_ } was the correct thing to use there. (I'm trying to avoid
> any mention of O-O for the moment.)
> say {} was a "what happens if I do this" exercise.
>
> What is this  -> ;; $_? is raw { #`(Block|170303864) … } output?
>
> On 9/18/16, Brent Laabs  wrote:
> > Remember you can call a block with parentheses:
> >
> >> say { 11 + 31 };
> > -> ;; $_? is raw { #`(Block|140268472711224) ... }
> >> say { 11 + 31 }();
> > 42
> >
> >
> > On Sun, Sep 18, 2016 at 12:58 PM, Elizabeth Mattijsen 
> > wrote:
> >
> >> I think you want:
> >>
> >>   .say for reverse lines;
> >>
> >> not sure what you are trying to achieve otherwise, but:
> >>
> >>say { }
> >>
> >> producing something like
> >>
> >>-> ;; $_? is raw { #`(Block|170303864) … }
> >>
> >> feels entirely correct to me.   :-)
> >>
> >>
> >> Liz
> >>
> >> > On 18 Sep 2016, at 21:52, Parrot Raiser <1parr...@gmail.com> wrote:
> >> >
> >> > This code:
> >> > 1 #! /home/guru/bin/perl6
> >> > 2
> >> > 3 # Ask for some lines and output them in reverse
> >> > 4 # Work out the appropriate EOF symbol for the OS
> >> > 5
> >> > 6 my $EOF = "CTRL-" ~ ($*DISTRO.is-win ?? "Z" !! "D");
> >> > 7
> >> > 8 say "Please enter some lines and end them with $EOF";
> >> > 9
> >> > 10 say { for reverse lines() {} };
> >> > 11
> >> > 12 # End
> >> > produces this:
> >> > Please enter some lines and end them with CTRL-D# obviously from
> >> line 8
> >> > -> ;; $_? is raw { #`(Block|170303864) ... }# but
> >> this?
> >>
> >>
> >
>

Re: Is this a bug?

[Trey Harris]

On Sun, Sep 18, 2016 at 16:49 Parrot Raiser <1parr...@gmail.com> wrote:

say { $_ } was the correct thing to use there. (I'm trying to avoid
> any mention of O-O for the moment.)
>
“Trying to avoid any mention of O-O” seems like a Perl 6 obfuscation or
golf constraint, not a desirable development or learning goal. Perl 6
doesn’t *force* you to write programs in an object-oriented style; you can
do it in functional or procedural or whatever style suits you. But you’re
going to have a bad time if you try to deny Perl 6’s fully OO nature. This
is in stark contrast to Perl 5, where OO was bolted on, and you could say
that the non-OO core was more “real” than the object-oriented sugar found
in modules you had to use.

Writing something like say($_) for reverse lines — which is what I think is
closest to what you wanted — isn’t any more or less “object-oriented” than
the more idiomatic .say for reverse lines;. In Perl 5, some rather
byzantine rules governed the use of the implicit $_; almost all of the
convenience afforded by those rules can be gained through the use of
topicalized objects, so the byzantine rules are gone — but the convenience
is gone too unless you’re willing to use the topic in the .foo style.

I think perhaps you see a dot, and dot signifies OO, so the .say... version
might *look* more OO than the say(... version in some sense, but that’s
pretty much cosmetic. You’re *using* some objects by interacting with the
Perl 6 core either way. It’s your choice not to write your logic in an OO
style, but you can’t prevent OO from happening during execution.

(This really isn’t some half-hearted attempt to force you into OO through
the backdoor; you really can skip OO for all *your* logic. You just can’t
pretend you’re not using an object-oriented language when you have to touch
code you’re not in control of, whether an OO library or the Perl 6 core.
But pretty much the entirety of what you need to know about OO if you
choose to do that is various syntax and some desiderata about the calling
semantics.)

say {} was a "what happens if I do this" exercise.
>
> What is this  -> ;; $_? is raw { #`(Block|170303864) … } output?
>
> On 9/18/16, Brent Laabs  wrote:
> > Remember you can call a block with parentheses:
> >
> >> say { 11 + 31 };
> > -> ;; $_? is raw { #`(Block|140268472711224) ... }
> >> say { 11 + 31 }();
> > 42
> >
> >
> > On Sun, Sep 18, 2016 at 12:58 PM, Elizabeth Mattijsen 
> > wrote:
> >
> >> I think you want:
> >>
> >>   .say for reverse lines;
> >>
> >> not sure what you are trying to achieve otherwise, but:
> >>
> >>say { }
> >>
> >> producing something like
> >>
> >>-> ;; $_? is raw { #`(Block|170303864) … }
> >>
> >> feels entirely correct to me.   :-)
> >>
> >>
> >> Liz
> >>
> >> > On 18 Sep 2016, at 21:52, Parrot Raiser <1parr...@gmail.com> wrote:
> >> >
> >> > This code:
> >> > 1 #! /home/guru/bin/perl6
> >> > 2
> >> > 3 # Ask for some lines and output them in reverse
> >> > 4 # Work out the appropriate EOF symbol for the OS
> >> > 5
> >> > 6 my $EOF = "CTRL-" ~ ($*DISTRO.is-win ?? "Z" !! "D");
> >> > 7
> >> > 8 say "Please enter some lines and end them with $EOF";
> >> > 9
> >> > 10 say { for reverse lines() {} };
> >> > 11
> >> > 12 # End
> >> > produces this:
> >> > Please enter some lines and end them with CTRL-D# obviously from
> >> line 8
> >> > -> ;; $_? is raw { #`(Block|170303864) ... }# but
> >> this?
> >>
> >>
> >
>
​

Re: Is this a bug?

[Brandon Allbery]

On Sun, Sep 18, 2016 at 4:49 PM, Parrot Raiser <1parr...@gmail.com> wrote:

> What is this  -> ;; $_? is raw { #`(Block|170303864) … } output?


It's the gist of a Block, which is what you asked for when you did a `say`
on an executable block.
Why do you believe `say { $_ }` is the right thing there? What were you
expecting it to do?

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

Re: Is this a bug?

[Elizabeth Mattijsen]

It is the .perl representation of a Block.

> On 18 Sep 2016, at 22:49, Parrot Raiser <1parr...@gmail.com> wrote:
> 
> say { $_ } was the correct thing to use there. (I'm trying to avoid
> any mention of O-O for the moment.)
> say {} was a "what happens if I do this" exercise.
> 
> What is this  -> ;; $_? is raw { #`(Block|170303864) … } output?
> 
> On 9/18/16, Brent Laabs  wrote:
>> Remember you can call a block with parentheses:
>> 
>>> say { 11 + 31 };
>> -> ;; $_? is raw { #`(Block|140268472711224) ... }
>>> say { 11 + 31 }();
>> 42
>> 
>> 
>> On Sun, Sep 18, 2016 at 12:58 PM, Elizabeth Mattijsen 
>> wrote:
>> 
>>> I think you want:
>>> 
>>>  .say for reverse lines;
>>> 
>>> not sure what you are trying to achieve otherwise, but:
>>> 
>>>   say { }
>>> 
>>> producing something like
>>> 
>>>   -> ;; $_? is raw { #`(Block|170303864) … }
>>> 
>>> feels entirely correct to me.   :-)
>>> 
>>> 
>>> Liz
>>> 
 On 18 Sep 2016, at 21:52, Parrot Raiser <1parr...@gmail.com> wrote:
 
 This code:
 1 #! /home/guru/bin/perl6
 2
 3 # Ask for some lines and output them in reverse
 4 # Work out the appropriate EOF symbol for the OS
 5
 6 my $EOF = "CTRL-" ~ ($*DISTRO.is-win ?? "Z" !! "D");
 7
 8 say "Please enter some lines and end them with $EOF";
 9
 10 say { for reverse lines() {} };
 11
 12 # End
 produces this:
 Please enter some lines and end them with CTRL-D# obviously from
>>> line 8
 -> ;; $_? is raw { #`(Block|170303864) ... }# but
>>> this?
>>> 
>>> 
>> 

Re: Is this a bug?

[Brent Laabs]

Remember you can call a block with parentheses:

> say { 11 + 31 };
-> ;; $_? is raw { #`(Block|140268472711224) ... }
> say { 11 + 31 }();
42


On Sun, Sep 18, 2016 at 12:58 PM, Elizabeth Mattijsen 
wrote:

> I think you want:
>
>   .say for reverse lines;
>
> not sure what you are trying to achieve otherwise, but:
>
>say { }
>
> producing something like
>
>-> ;; $_? is raw { #`(Block|170303864) … }
>
> feels entirely correct to me.   :-)
>
>
> Liz
>
> > On 18 Sep 2016, at 21:52, Parrot Raiser <1parr...@gmail.com> wrote:
> >
> > This code:
> > 1 #! /home/guru/bin/perl6
> > 2
> > 3 # Ask for some lines and output them in reverse
> > 4 # Work out the appropriate EOF symbol for the OS
> > 5
> > 6 my $EOF = "CTRL-" ~ ($*DISTRO.is-win ?? "Z" !! "D");
> > 7
> > 8 say "Please enter some lines and end them with $EOF";
> > 9
> > 10 say { for reverse lines() {} };
> > 11
> > 12 # End
> > produces this:
> > Please enter some lines and end them with CTRL-D# obviously from
> line 8
> > -> ;; $_? is raw { #`(Block|170303864) ... }# but
> this?
>
>

Re: Is this a bug?

[Elizabeth Mattijsen]

I think you want:

  .say for reverse lines;

not sure what you are trying to achieve otherwise, but:

   say { }

producing something like

   -> ;; $_? is raw { #`(Block|170303864) … }

feels entirely correct to me.   :-)


Liz

> On 18 Sep 2016, at 21:52, Parrot Raiser <1parr...@gmail.com> wrote:
> 
> This code:
> 1 #! /home/guru/bin/perl6
> 2
> 3 # Ask for some lines and output them in reverse
> 4 # Work out the appropriate EOF symbol for the OS
> 5
> 6 my $EOF = "CTRL-" ~ ($*DISTRO.is-win ?? "Z" !! "D");
> 7
> 8 say "Please enter some lines and end them with $EOF";
> 9
> 10 say { for reverse lines() {} };
> 11
> 12 # End
> produces this:
> Please enter some lines and end them with CTRL-D# obviously from line 8
> -> ;; $_? is raw { #`(Block|170303864) ... }# but this?