Re: available operator characters

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Juerd

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May 6, 2005, 12:49:44 PM5/6/05
to Luke Palmer, perl6-l...@perl.org
Luke Palmer skribis 2005-05-06 10:43 (-0600):
> Why the %!@ would you ignore that!? :-)

I hate my brain. Now I wonder if Bool.does(Hash). Does it? :)


Juerd
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Luke Palmer

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May 6, 2005, 12:43:07 PM5/6/05
to Juerd, perl6-l...@perl.org
On 5/6/05, Juerd <ju...@convolution.nl> wrote:
> To try and make it easier to pick (ASCII) operators, a simple table of
> what's given away and what's available. Please let me know if there are
> any mistakes.

Thanks! Here's an annotated bit for each ?.

> If anyone knows how to fill in the "???" parts, be my guest!
> ! not none() ???

Nope. In order to create those, you just need to say none(). There
is no operator form.

> !! AVAILABLE? AVAILABLE?

Given prefix:<?>, I suppose that is available.

> @@ AVAILABLE? AVAILABLE

Yep.

> $$ AVAILABLE? AVAILABLE

Nope. Not in term position. I hardly think it would be a good idea
to make an operator out of it (or even a single $), however.

> % hash mod
> %% AVAILABLE? AVAILABLE?

Yes.

> \\ AVAILABLE? AVAILABLE

Uh huh.

> == AVAILABLE? num eq

Fortunately yes. Let's keep it that way.

> --> AVAILABLE AVAILABLE?

I suppose it is. That would destroy Damian's favorite little idiom:

while ($x --> 0) {...}

But I don't think that's a huge loss. :-)

> <-> don't touch it, I'm going to use this for -> is rw :)

In operator position. In term position it is a single-quoted -.

> ?? AVAILABLE? ternary

Yep.

> :: namespace ternary

That's "class sigil" in term position. Separating namespaces never
have preceding whitespace, so they're always part of some larger term.

> \w+ infix only
> x passive repeat
> xx passive repeat
> X active repeat ???
> XX active repeat ???

Those two haven't been blessed, and, though I don't have the message,
I think I remember Larry being a little hesitant about adding those.

> Y zip()
> many still available!
>
> With double characters (like ~~), "AVAILABLE?" means that if we start
> using that, stacking of the single thing will start requiring
> whitespace, as with = and == in $foo = =$fh)
>
> "ws?" means that whitespace may be needed for disambiguation.
>
> I left out colon and semicolon because they're too special to fit in a
> term|op table. I think it's more than safe to assume they're taken :)

Um, yes.

> <> is more flexible than {}, [] and () because it's a quoting operator
> (the inside is not an expression).
>
> I think it's best to ignore entirely the fact that we can use more
> triple character proper operators :)

Why the %!@ would you ignore that!? :-)

Luke

Juerd

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May 6, 2005, 12:54:45 PM5/6/05
to Luke Palmer, perl6-l...@perl.org
Luke Palmer skribis 2005-05-06 10:43 (-0600):
> Thanks! Here's an annotated bit for each ?.

Only the triple-questionmarks were meant as questions. I should have
picked a better meta-operator for AVAILABLE?. But apparently, even
though I didn't mean to ask so many questions, there still are answers I
hadn't thought about.

Thanks for your detailed reply!

> > ! not none() ???
> Nope. In order to create those, you just need to say none(). There
> is no operator form.

Do we have postfix ! for factorials, or is it available?

> > $$ AVAILABLE? AVAILABLE
> Nope. Not in term position. I hardly think it would be a good idea
> to make an operator out of it (or even a single $), however.

Why would a single $ be a bad operator? We already have the single % for
mod, and that works well. I think @ and $ are perfect candidates for
infix operators.

> I suppose it is. That would destroy Damian's favorite little idiom:
> while ($x --> 0) {...}

aww :)

> That's "class sigil" in term position. Separating namespaces never
> have preceding whitespace, so they're always part of some larger term.

Is there any important difference between "namespace" and "class" in
Perl 6? Do they share the same, ehm, namespace? (classspace?)

Thanks again.

Juerd

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May 6, 2005, 12:24:00 PM5/6/05
to perl6-l...@perl.org
To try and make it easier to pick (ASCII) operators, a simple table of
what's given away and what's available. Please let me know if there are
any mistakes.

If anyone knows how to fill in the "???" parts, be my guest!

\W+ Term (pre|circ) Operator (post|in)
` AVAILABLE AVAILABLE
`` AVAILABLE AVAILABLE
~ stringy concat
~... string bitops
~~ AVAILABLE? smart match
! not none() ???
!= ! ==
!~ ! ~~
!! AVAILABLE? AVAILABLE?
@ array AVAILABLE
@@ AVAILABLE? AVAILABLE
# comment comment
$ scalar AVAILABLE
$$ AVAILABLE? AVAILABLE


% hash mod
%% AVAILABLE? AVAILABLE?

^ AVAILABLE one()
^^ AVAILABLE xor
& sub all()
&& (clash) and
* splat multiply
** steam roller power
() group sub (deref+)call (no ws)
()? (clash) AVAILABLE (ws)
\ ref AVAILABLE
\\ AVAILABLE? AVAILABLE
| AVAILABLE any()
|| AVAILABLE or
[] aref|reduce array (deref+)subscript (no ws)
[]? (clash) AVAILABLE (ws)
{} href|closure hash (deref+)subscript (no ws)
{}? (clash) AVAILABLE (ws)
+ numeric add
+... numeric bitops
++ preinc postinc
= iterate assign
=> AVAILABLE pair
== AVAILABLE? num eq
==> pipe pipe
- 0- substract
-> sub sub
-- predec postdec
--> AVAILABLE AVAILABLE?
'' q AVAILABLE ('|'')
"" qq AVAILABLE ("|"")
, ??? list sep
,, ??? ???
<> qw hash (deref+)subscript (no ws)
<>? (clash) AVAILABLE (ws)
< (clash) less-than (ws)
<= (clash) le (ws)
<== pipe pipe


<-> don't touch it, I'm going to use this for -> is rw :)

> AVAILABLE (ws) greater-than
>= AVAILABLE (ws) ge (ws?)
<<>> qw hash (deref+)subscript (no ws)
<<[>>]? (clash) AVAILABLE (ws)
<< hyper hyper
>> hyper hyper
. $_. (deref+)subscript|method call
/ (clash) divide
// m// defined-or
? true AVAILABLE
?... boolean bitops
?? AVAILABLE? ternary
:: namespace ternary

\w+ infix only
x passive repeat
xx passive repeat
X active repeat ???
XX active repeat ???

Y zip()
many still available!

With double characters (like ~~), "AVAILABLE?" means that if we start
using that, stacking of the single thing will start requiring
whitespace, as with = and == in $foo = =$fh)

"ws?" means that whitespace may be needed for disambiguation.

I left out colon and semicolon because they're too special to fit in a
term|op table. I think it's more than safe to assume they're taken :)

<> is more flexible than {}, [] and () because it's a quoting operator


(the inside is not an expression).

I think it's best to ignore entirely the fact that we can use more
triple character proper operators :)

Juerd

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May 6, 2005, 1:21:07 PM5/6/05
to Patrick R. Michaud, perl6-l...@perl.org
Patrick R. Michaud skribis 2005-05-06 12:20 (-0500):
> Ummm, what about C<not> and C<true> ?

I'm sticking to non-words here, as I mentally parse not and true as
single-arg subs, single-arg subs as unary operators, etcetera. I can't
help it, but I have absolutely no idea how to determine the difference.
Is it &prefix:<not> or just &not? I have no idea. I do know that it's
&infix:<x>, not &x.

Juerd

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May 6, 2005, 1:09:47 PM5/6/05
to Luke Palmer, perl6-l...@perl.org
Luke Palmer skribis 2005-05-06 11:04 (-0600):
> Because we're marking all of our singular nouns with $, and you have
> to admit, the $ sigil in perl code is much more common than @ and %.
> What good is a noun marker if you mark some of your verbs with it too?

But verbing doesn't weird language at all!

Patrick R. Michaud

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May 6, 2005, 1:20:38 PM5/6/05
to Juerd, perl6-l...@perl.org
On Fri, May 06, 2005 at 06:24:00PM +0200, Juerd wrote:
> To try and make it easier to pick (ASCII) operators, a simple table of
> what's given away and what's available. Please let me know if there are
> any mistakes.
>
> If anyone knows how to fill in the "???" parts, be my guest!
> [...]
>
> \w+ infix only

Ummm, what about C<not> and C<true> ?

Pm

Luke Palmer

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May 6, 2005, 1:04:20 PM5/6/05
to Juerd, perl6-l...@perl.org
On 5/6/05, Juerd <ju...@convolution.nl> wrote:
> Luke Palmer skribis 2005-05-06 10:43 (-0600):
> > > ! not none() ???
> > Nope. In order to create those, you just need to say none(). There
> > is no operator form.
>
> Do we have postfix ! for factorials, or is it available?

No, it's available. What would we use to demonstrate how to write
postfix operators (not to mention recursive functions) if we made that
standard?

> > > $$ AVAILABLE? AVAILABLE
> > Nope. Not in term position. I hardly think it would be a good idea
> > to make an operator out of it (or even a single $), however.
>
> Why would a single $ be a bad operator? We already have the single % for
> mod, and that works well. I think @ and $ are perfect candidates for
> infix operators.

Because we're marking all of our singular nouns with $, and you have


to admit, the $ sigil in perl code is much more common than @ and %.
What good is a noun marker if you mark some of your verbs with it too?

Luke

> > That's "class sigil" in term position. Separating namespaces never
> > have preceding whitespace, so they're always part of some larger term.
>
> Is there any important difference between "namespace" and "class" in
> Perl 6? Do they share the same, ehm, namespace? (classspace?)

Just making sure you weren't considering the :: in $Foo::Bar to be an
operator. There is a difference between class and namespace in that a
class is a type and a namespace isn't. But I think you mark them both
with the :: sigil in this case.

Luke

Rob Kinyon

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May 6, 2005, 1:31:43 PM5/6/05
to perl6-l...@perl.org
> I'm sticking to non-words here, as I mentally parse not and true as
> single-arg subs, single-arg subs as unary operators, etcetera. I can't
> help it, but I have absolutely no idea how to determine the difference.
> Is it &prefix:<not> or just &not? I have no idea. I do know that it's
> &infix:<x>, not &x.

Though, P6 mayl give us the ability to create circumfix operators (as
seen in the entire reduce thread). I think that syntax will also allow
for functions to be parsed as infix operators, right?

Rob

Larry Wall

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May 6, 2005, 2:11:17 PM5/6/05
to perl6-l...@perl.org
On Fri, May 06, 2005 at 01:31:43PM -0400, Rob Kinyon wrote:
: > I'm sticking to non-words here, as I mentally parse not and true as

Sure, but in that case we usually call them methods. :-)

Larry

Larry Wall

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May 6, 2005, 2:25:31 PM5/6/05
to perl6-l...@perl.org
On Fri, May 06, 2005 at 06:49:44PM +0200, Juerd wrote:
: Luke Palmer skribis 2005-05-06 10:43 (-0600):

: > Why the %!@ would you ignore that!? :-)
:
: I hate my brain. Now I wonder if Bool.does(Hash). Does it? :)

Any Object does Hash, and treats any argumentless method as a potential
hash key. So Bool is likely to recognize $boolean<bit> and return 0
or 1, possibly disguised as Bool::true or Bool::false. On the other
hand, a low-level bool type might not choose to box itself to Bool just
so you can treat it as a hash and get the low level value back out.
Then again, it might. :-)

Larry

Larry Wall

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May 6, 2005, 2:28:05 PM5/6/05
to perl6-l...@perl.org
On Fri, May 06, 2005 at 11:25:31AM -0700, Larry Wall wrote:
: Any Object does Hash, and treats any argumentless method as a potential
: hash key.

I should also point out that the main reason for this is to allow
easier translation of Perl 5 idioms to Perl 6 without having to guess
whether $foo contains an unblessed hash ref or a real Perl 6 object.
We're not actually recommending peole use hash notation to call
attribute methods.

Larry

Juerd

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May 6, 2005, 8:15:21 PM5/6/05
to perl6-l...@perl.org
Juerd skribis 2005-05-06 18:24 (+0200):
> | AVAILABLE any()

We can use this for labels:

|foo| for ... {
while ... {
...;
next foo if ...;
}
}

It'll confuse the heck out of Ruby coders, but I do like this syntax. It
makes labels stand out, as was one of the requirements, and it puts a
little less strain on the colon.

(Now, if we really want to bug Rubyfolk, we could make labels per block
instead of per statement, and put them inside the curlies:

for ... { |foo|
while ... {
...;
next foo if ...;
}
}

*evil grin*)

Larry Wall

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May 6, 2005, 9:15:00 PM5/6/05
to perl6-l...@perl.org
On Fri, May 06, 2005 at 10:43:07AM -0600, Luke Palmer wrote:
: > :: namespace ternary

:
: That's "class sigil" in term position. Separating namespaces never
: have preceding whitespace, so they're always part of some larger term.

Really more like a package sigil, which can be used as a module, class,
role, or type sigil.

: > X active repeat ???


: > XX active repeat ???
:
: Those two haven't been blessed, and, though I don't have the message,
: I think I remember Larry being a little hesitant about adding those.

The question is whether to treat the left arg the same way we treat
attribute defaults, with one free closure call. We could say that

{ rand 10 } x 100
{ rand 10 } xx 100

should just automatically call the closure on the left repeatedly. In
the rare, rare case that you want to actually replicate a closure, you'd
have to say

{ { rand 10 } } x 100
{ { rand 10 } } xx 100

Then we save two operators. We could also pass the counter in as $_:

{ foo($_) } xx 100; # call foo(0), foo(1)...foo(99)

Which means

@chars = { substr($x, $_, 1) } xx $x.chars;

would be a silly way to write a split ''.

Larry

Larry Wall

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May 6, 2005, 9:22:52 PM5/6/05
to perl6-l...@perl.org
On Fri, May 06, 2005 at 06:24:00PM +0200, Juerd wrote:
: {} href|closure hash (deref+)subscript (no ws)
: {}? (clash) AVAILABLE (ws)

s/AVAILABLE/statement block/

Actually, I'd try to find a way to combine all the paired ws-dependent
entries onto the same line, since splitting them to separate lines
induces a fake clash. Maybe

{} href|closure hash (deref+)subscript / statement block

or some such. (But then you need to put postfix first in the heading.)

Larry

Juerd

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May 6, 2005, 9:52:48 PM5/6/05
to perl6-l...@perl.org
Larry Wall skribis 2005-05-06 18:22 (-0700):

> (But then you need to put postfix first in the heading.)

The heading uses junctions, and junctions are unordered ;)

Matt Creenan

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May 7, 2005, 1:47:08 AM5/7/05
to Mark A. Biggar, Juerd, perl6-l...@perl.org
On Sat, 07 May 2005 01:12:02 -0400, Mark A. Biggar <ma...@biggar.org> wrote:

>
> Actually if we define |...| at all, I'd prefer it mean abs(), its usual
> mathmatical meaning.
>

I agree. I think || is just confusing.

I thought about $blockname <= { ... }, but <= is obviously taken, as is <==

So here's some random ideas that probably make no sense ($ can be
optional.. don't know)

$blockname <=: for 1..5 {
...
}


$blockname :=> for 1..5 {
...
}


for 1..5 {
...
} $blockname;


for 1..5 {
...
} <=: $blockname;


$blockname for 1..5 {
...
} $blockname;


$blockname -- for 1..5 {
...
}


for 1..5 {
...
} -- $blockname;


$blockname @ for 1..5 { # Yeah I know @ is probably impossible
...
} $blockname;


for 1..5 {
...
} @ $blockname;


$blockname ■ for 1..5 {
...
}

Mark A. Biggar

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May 7, 2005, 1:12:02 AM5/7/05
to Juerd, perl6-l...@perl.org
Juerd wrote:

> Juerd skribis 2005-05-06 18:24 (+0200):
>
>> | AVAILABLE any()
>
>
> We can use this for labels:
>
> |foo| for ... {
> while ... {
> ...;
> next foo if ...;
> }
> }
>
> It'll confuse the heck out of Ruby coders, but I do like this syntax. It
> makes labels stand out, as was one of the requirements, and it puts a
> little less strain on the colon.
>
> (Now, if we really want to bug Rubyfolk, we could make labels per block
> instead of per statement, and put them inside the curlies:
>
> for ... { |foo|
> while ... {
> ...;
> next foo if ...;
> }
> }
>
> *evil grin*)

Actually if we define |...| at all, I'd prefer it mean abs(), its usual
mathmatical meaning.


--
ma...@biggar.org
mark.a...@comcast.net

Matt Creenan

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May 7, 2005, 4:14:30 AM5/7/05
to perl6-l...@perl.org
On Sat, 07 May 2005 01:47:08 -0400, Matt Creenan <ma...@weakmind.org> wrote:

>
> So here's some random ideas that probably make no sense ($ can be
> optional.. don't know)
>

> *snip*
>

That brings me to another idea. Is $_ as an array used? @_?

This relates back to the discussion on topics. Could be use @_ as an
array of topics, or was that already proposed?

So you could reference @_ as an indexed array, @_[0] being the current
topic, or maybe @_[1] and having @_[0] as the number of topics. Then you
could reference %_ as a hashed array, where you give the blockname to get
that blocks topic/invocant.

Let's assume that naming blocks was done like such:

block1 -- for 1..5 {
block2 -- for 1..3 {
say @_[1] ~ @_[2];
}
}

or

block1 -- for 1..5 {
block2 -- for 1..3 {
say %_<block2> ~ %_<block1>;
}
}

I can't remember if barewords are allowed, so pretend I have '' around
those blocknames for the hashes if they aren't :)

Also, the block names could then be used for next/last/continue/whatever.

next block2;

Or maybe my sleeping pills are turning me insane.

Juerd

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May 7, 2005, 8:20:30 AM5/7/05
to Mark A. Biggar, perl6-l...@perl.org
Mark A. Biggar skribis 2005-05-06 22:12 (-0700):

> Actually if we define |...| at all, I'd prefer it mean abs(), its usual
> mathmatical meaning.

No. We can't just use circumfix |...| with arbitrary expressions in it,
because | is taken as an infix operator. It has to be quoteish (like <>
(this is why there can be infix < and >, even though <> is taken)), or
you end up with ugly parens. Only mirrored sets are useful for arbitrary
expressions, the same thing left and right makes things very hard. But
for quoteish operators, that's no problem: '', "", //, and perhaps ||.
Labels would also specifically be limited to \w+.

And personally I could not care any less about the mathematical meaning.
I have never cared about that with other operators. We don't have << and
>> to mean much less than and much greater than, do we? Should we?

Juerd

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May 7, 2005, 8:30:44 AM5/7/05
to Matt Creenan, perl6-l...@perl.org
Matt Creenan skribis 2005-05-07 4:14 (-0400):

> That brings me to another idea. Is $_ as an array used? @_?

The default signature of subs is (*@_).

Juerd

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May 7, 2005, 8:23:15 AM5/7/05
to Matt Creenan, Mark A. Biggar, Juerd, perl6-l...@perl.org
Matt Creenan skribis 2005-05-07 1:47 (-0400):

> I thought about $blockname <= { ... }, but <= is obviously taken, as is <==
> $blockname <=: for 1..5 {
> $blockname :=> for 1..5 {
> } $blockname;
> } <=: $blockname;
> } $blockname;
> $blockname for 1..5 {
> $blockname -- for 1..5 {
> } -- $blockname;

> } $blockname;
> $blockname @ for 1..5 { # Yeah I know @ is probably impossible
> } @ $blockname;
> $blockname ??? for 1..5 {

IMO, all of these are worse than "label:". And most of your syntaxes
limit labels to blocks, while currently they can be placed before any
statement, and it has been said that this behaviour is preferred.

Luke Palmer

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May 7, 2005, 1:31:47 PM5/7/05
to perl6-l...@perl.org
On 5/6/05, Larry Wall <la...@wall.org> wrote:
> The question is whether to treat the left arg the same way we treat
> attribute defaults, with one free closure call. We could say that
>
> { rand 10 } x 100
> { rand 10 } xx 100
>
> should just automatically call the closure on the left repeatedly. In
> the rare, rare case that you want to actually replicate a closure, you'd
> have to say
>
> { { rand 10 } } x 100
> { { rand 10 } } xx 100

But we also have to remember that, given:

my @codes = { { rand 10 } } xx 100;
say @codes[0] == @codes[1]; # 0

You're not duplicating one closure as you are with:

my @others = { rand 10 } xx 100;

Without the closure semantics of xx. If you made @codes[0] do some
role, it would only apply to @codes[0], but if you made @others[0] do
some role, it would apply to every closure in @others.

Luke

Larry Wall

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May 7, 2005, 3:43:56 PM5/7/05
to perl6-l...@perl.org
On Sat, May 07, 2005 at 02:23:15PM +0200, Juerd wrote:
: Matt Creenan skribis 2005-05-07 1:47 (-0400):

: > I thought about $blockname <= { ... }, but <= is obviously taken, as is <==
: > $blockname <=: for 1..5 {
: > $blockname :=> for 1..5 {
: > } $blockname;
: > } <=: $blockname;
: > } $blockname;
: > $blockname for 1..5 {
: > $blockname -- for 1..5 {
: > } -- $blockname;
: > } $blockname;
: > $blockname @ for 1..5 { # Yeah I know @ is probably impossible
: > } @ $blockname;
: > $blockname ??? for 1..5 {
:
: IMO, all of these are worse than "label:". And most of your syntaxes
: limit labels to blocks, while currently they can be placed before any
: statement, and it has been said that this behaviour is preferred.

Labels will remain on statements. However, you can sneak a statement
(including its label) into the middle of an expression by using "do":

$outer = do LINE: for =$IN {...; $inner ==> leave LINE }

Note that "do" no longer requires braces unless you wish to continue the
expression after the do. Which we can get away with because do-SUB
is gone and do-File is renamed to evalfile or some such. Maybe it
can be demoted to

eval requirefinder($filename);

since we're trying to discourage use of do-File anyway, and we can probably
abstract out the parts that require and do-File have in common.

Larry

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