On Tue, Apr 05, 2005 at 04:00:09PM +0200, Thomas Sandlaß wrote:
: Larry Wall wrote:
: >Roles cannot be derived from, so they're always final in that sense.
: >We should probably consider them closed by default as well, or at least
: >closed after first use. If a role specifies implementation, it's
HaloO Larry,
you wrote:
On Thu, Mar 31, 2005 at 06:35:06PM +0200, Thomas Sandlaß wrote:
: Is typing optional in the sense that it is no syntax error but
: otherwise ignored? To me this is pain but no gain :(
Well, you guys keep ignoring the answer. Let me put it a bit more
mathematically. The inf
Larry Wall wrote:
Roles cannot be derived from, so they're always final in that sense.
We should probably consider them closed by default as well, or at least
closed after first use. If a role specifies implementation, it's always
default implementation, so overriding implementation always occurs
On Thu, Mar 31, 2005 at 01:11:37PM -0500, Aaron Sherman wrote:
: If you declare a variable to be of a type (let's even say a class to be
: specific), then you have hinted to the compiler as to the nature of that
: variable, but nothing is certain.
:
: That is to say that the compiler cannot:
:
:
On Thu, 2005-03-31 at 15:25, chromatic wrote:
> On Thu, 2005-03-31 at 13:11 -0500, Aaron Sherman wrote:
>
> I can't answer most of these well. However...
> Open-Closed is a great idea until the most natural and easiest way to do
> something is to to redefine a little bit of the world.
You seem
I'm no expert, but here's my take:
On Thu, Mar 31, 2005 at 01:11:37PM -0500, Aaron Sherman wrote:
> If you declare a variable to be of a type (let's even say a class to be
> specific), then you have hinted to the compiler as to the nature of that
> variable, but nothing is certain.
>
> That is to
On Thu, 2005-03-31 at 13:11 -0500, Aaron Sherman wrote:
I can't answer most of these well. However...
> > One additional wrinkle is that *anyone* is allowed to declare a
> > class non-cooperative (open or non-final) during *any* part of the
> > compilation
>
> ... even after it is declared fina
On Thu, 2005-03-31 at 11:51, Larry Wall wrote:
> my X $a;
>
> is *necessary* but not *sufficient* to do method existence testing in
> standard Perl 6 at compile time. You can do it IFF you have the class
> information AND the classes are willing to cooperate in your scheme.
> In the current
On Thu, Mar 31, 2005 at 06:35:06PM +0200, Thomas Sandlaß wrote:
: Is typing optional in the sense that it is no syntax error but
: otherwise ignored? To me this is pain but no gain :(
Well, you guys keep ignoring the answer. Let me put it a bit more
mathematically. The information in
my X $
Miroslav Silovic wrote:
Remember, you can even change the class of instanced objects using
'does' (or 'but', but it'll at least copy the object). And as the
example above shows, this is statically intractable - it can happen in a
sub in a different autoloaded module.
Sorry this is a well establi
[EMAIL PROTECTED] wrote:
Er, isn't that not just the wrong way around? The point is to do the
bookkeeping that an object is needed that does .meth() and that it
is stored in $a, and to complain when that is not the case when it
should be. The earlier the better.
I don't understand why writing 'my X
Thomas Sandlaà wrote:
Int|Str <: Str && Str <: Int|Str && Int|Str <: Int && Int <: Int|Str
holds.
Uhh, I hardly believe that it was me writing that last night!
Int|Str is of course a proper supertype of Int and Str respectively.
So we really have: Str <: Str|Int && Int <: Str|Int, which warps us
Aaron Sherman writes:
> > Please think carefully about how dynamic you want Perl 6 to be
> > > Dynamic is good, but there's such a thing as too much of a good thing.
> >
> > We'd like Perl 6 to be as dynamic as Perl 5.
>
> We'd think that is impossible. Perl 5 had full control of the
> run-ti
On Wed, 2005-03-30 at 18:35 -0500, Aaron Sherman wrote:
> When the Perl 6 compiler sees:
>
> my X $a;
> $a.m(1);
>
> What should it do?
>
> Options:
>
> * Accept the method call regardless of the definition of X
> * Accept the method call if it matches the signature
On Wed, 2005-03-30 at 17:09, Luke Palmer wrote:
> Aaron Sherman writes:
> > What I do not think should be allowed (and I may be contradicting
> > Larry here, which I realize is taking my life in my hands ;) is
> > violating the compile-time view of the "static" type tree.
>
> That sentence is ge
Thomas Sandlaà wrote:
Any might just be a glb (greatest upper bound) of Int and Str, written
Sorry that should read lub (least upper bound). Glb means greatest lower
bound and is spelled Int&Str or all(Int,Str) in Perl6.
--
TSa (Thomas SandlaÃ)
Luke Palmer wrote:
Okay, now we're starting to talk past each other. I /think/ Thomas
orignially suggested that we use type inference to determine whether to
lvalue cast an argument or not, which is what I got all worked up about.
Actually I was returning to the subject of co- or contravariance of
According to Luke Palmer:
> [Perl 5] had to construct lvalues out of all arguments (for which
> that made sense) because the sub might modify them.
No, actually, that wasn't the reason. Perl 5 passes all values by
implicit mutable reference because it's faster, not because it's
better. I suspect
Aaron Sherman writes:
> On Wed, 2005-03-30 at 13:53, Luke Palmer wrote:
>
> > class CodeProxy {
> > has Code $.code is rw;
> > sub call ($a) {
> > $.code($a);
> > }
> > }
>
> > This is valid Perl 6, and anyone who says otherwise (because of type
> > sig
Aaron Sherman writes:
> What I do not think should be allowed (and I may be contradicting
> Larry here, which I realize is taking my life in my hands ;) is
> violating the compile-time view of the "static" type tree.
That sentence is getting pretty C++-derived-like, which Perl is hardly
anymore.
Thomas Sandlaà writes:
> Luke Palmer wrote:
> >class CodeProxy {
> >has Code $.code is rw;
> >sub call ($a) {
> >$.code($a);
> >}
> >}
> >
> >This is valid Perl 6,
>
> Hmm, a sub in a class? I guess that should be a method. OTOH a
> class is just a funny
Thomas Sandlaà writes:
> Aaron Sherman wrote:
> >No, that was most of the point. &foo did not declare a return type, and
> >while my code was simplistic, we obviously cannot be certain what &foo
> >might return in the general case.
>
> Sorry that I've spoiled that. But I wonder if it's just in the
Aaron Sherman wrote:
No, that was most of the point. &foo did not declare a return type, and
while my code was simplistic, we obviously cannot be certain what &foo
might return in the general case.
Sorry that I've spoiled that. But I wonder if it's just in the examples
here on the list or a general
chromatic wrote:
A compiler that assumes incorrectly and disallows programmers to do
useful things because its holds those assumptions as precious is wrong
-- especially in cases where even the programmer can't tell if code is
valid or invalid until the program actually runs.
Me neither. One should
Luke Palmer wrote:
class CodeProxy {
has Code $.code is rw;
sub call ($a) {
$.code($a);
}
}
This is valid Perl 6,
Hmm, a sub in a class? I guess that should be a method. OTOH a
class is just a funny module, so might be OK. But that is the
syntax realm.
a
On Wed, 2005-03-30 at 15:27 -0500, Aaron Sherman wrote:
> Like I said, if you allow run-time munging of the type interfaces, then
> you can't tell if this is valid or invalid:
>
> my X $a;
> $a.m(1);
>
> you have to allow it always, regardless of the definition of X. In fact,
> you c
On Wed, 2005-03-30 at 14:57, chromatic wrote:
> I certainly plan to continue to instrument code at runtime (and not just
> really slushy, partially slushy, and permafrost compile time).
That's FINE, and no one should stop you!
What I was referring to was only the items that an interface definiti
On Wed, 2005-03-30 at 14:29 -0500, Aaron Sherman wrote:
> What I do not think should be allowed (and I may be contradicting Larry
> here, which I realize is taking my life in my hands ;) is violating the
> compile-time view of the "static" type tree. That is, you can load an
> object "foo" at run-
On Wed, Mar 30, 2005 at 12:05:12PM +0200, Thomas Sandlaß wrote:
: If I understand you correctly the use statement is more like a
: linker/loader directive than a compile time interface include?
That is up to the module being used. "use" is a linker, but it's
only required to link enough informati
On Wed, 2005-03-30 at 13:53, Luke Palmer wrote:
> class CodeProxy {
> has Code $.code is rw;
> sub call ($a) {
> $.code($a);
> }
> }
> This is valid Perl 6, and anyone who says otherwise (because of type
> signatures) is changing the Perl philosophy too
On Wed, 2005-03-30 at 13:17, Thomas Sandlaß wrote:
> HaloO Luke,
>
> you wrote:
> > No, I think I agree with you here. But what happens if you change
> > you're second-to-last line to:
> >
> > my $a = foo();
> > $a.meth() = 8;
> >
> > Perl 6 is both a statically typed language and a dyn
Larry Wall wrote:
I think it's perfectly fine for the compiler to make use of whatever
information it has. The trick is to never make any unwarranted
assumptions, such as "Nobody will ever add another class with an 'm'
method."
Er, isn't that not just the wrong way around? The point is to do the
b
Thomas Sandlaà writes:
> And of course the builtin functionality and the packages available
> from CPAN save the typical small scale programmer from extensive
> declarations. But to use a complex module you have to read
> documentation to get the idea to call .meth() in the first place.
> And then
On Wed, 2005-03-30 at 11:40, Luke Palmer wrote:
> No, I think I agree with you here. But what happens if you change
> you're second-to-last line to:
>
> my $a = foo();
> $a.meth() = 8;
>
> Perl 6 is both a statically typed language and a dynamically typed
> language, and the problems th
HaloO Luke,
you wrote:
No, I think I agree with you here. But what happens if you change
you're second-to-last line to:
my $a = foo();
$a.meth() = 8;
Perl 6 is both a statically typed language and a dynamically typed
language, and the problems that I am addressing are mostly about the
dyna
On Wed, Mar 30, 2005 at 09:40:26AM -0700, Luke Palmer wrote:
: There _is_ a way to do it, actually, but we need to really screw around
: with what kinds of things are inferred. In the case:
:
: my $a;
: $a.m(1);
:
: We assign the type "objects with an 'm' method that can take a single
:
Aaron Sherman writes:
> On Tue, 2005-03-29 at 16:00 -0700, Luke Palmer wrote:
>
> > Unless the caller can't see the signature, as is the case with methods.
>
> I need to understand this piece.
>
> In this code:
>
> class X {
> method meth() {...}
> }
> class Y is
On Tue, 2005-03-29 at 16:00 -0700, Luke Palmer wrote:
> Unless the caller can't see the signature, as is the case with methods.
I need to understand this piece.
In this code:
class X {
method meth() {...}
}
class Y is X {
method meth() is
Luke Palmer wrote:
Unless the caller can't see the signature, as is the case with methods.
[..]
Again, this can't be done unless you know the signature. And in fact,
we can't do type inference on methods unless we do type inference
everywhere, which we can't do if we want an autoloader.
This sound
Thomas Sandlaà writes:
> Luke Palmer wrote:
> >So if you want things modified, you'd have to pass in a reference.
> >Arrays and hashes would not generally have this restriction, since we
> >pass references of those guys anyway.
>
> But I would really like to see a declaration of any possible modif
Luke Palmer wrote:
So if you want things modified, you'd have to pass in a reference.
Arrays and hashes would not generally have this restriction, since we
pass references of those guys anyway.
But I would really like to see a declaration of any possible modification
in the interface of a sub. Othe
> "LW" == Larry Wall <[EMAIL PROTECTED]> writes:
LW> : then how would you assign undef to the only element of the
LW> array? would this : be needed:
LW> :
LW> : @a = ( undef ) ;# same as p5?
LW> :
LW> : vs.
LW> : @a = undef ;# like undef @a
On Sat, Mar 26, 2005 at 11:57:48PM -0500, Uri Guttman wrote:
: > "LW" == Larry Wall <[EMAIL PROTECTED]> writes:
:
: LW> That being said, in Perl 5, if you say
:
: LW> @a = undef;
:
: LW> you don't get an undefined array. I'd like to make undef smart enough
: LW> about list conte
On Sun, Mar 27, 2005 at 12:04:39AM -0500, Uri Guttman wrote:
: > "LW" == Larry Wall <[EMAIL PROTECTED]> writes:
:
: LW> As I mentioned in my other message, I think we should not assume that
: LW> Perl 6 works the same in this regard as Perl 5 does. There needs to be
: LW> something we c
> "LW" == Larry Wall <[EMAIL PROTECTED]> writes:
LW> As I mentioned in my other message, I think we should not assume that
LW> Perl 6 works the same in this regard as Perl 5 does. There needs to be
LW> something we can return that not only means (), but means also means
LW> "You're ho
> "LW" == Larry Wall <[EMAIL PROTECTED]> writes:
LW> That being said, in Perl 5, if you say
LW> @a = undef;
LW> you don't get an undefined array. I'd like to make undef smart enough
LW> about list contexts that @a actually does end up undefined in Perl 6.
LW> That is, in scala
On Sat, Mar 26, 2005 at 03:13:07AM -0700, Luke Palmer wrote:
: Chip Salzenberg writes:
: > I'm working on enhancing Perl6::Subs[*] to support more parameter
: > traits than just C. I have some questions about
: > parameters and traits. (These questions all apply to pure Perl 6,
: > which I know I
On Sat, Mar 26, 2005 at 03:45:30PM -0500, Chip Salzenberg wrote:
: According to Rod Adams:
: > Chip Salzenberg wrote:
: > >* As far as I can tell, the choice of spelling an array parameter
: > > C or C is entirely cosmetic: both @a and
: > > $a are capable of holding an Array reference. Is there
According to Rod Adams:
> Chip Salzenberg wrote:
> >* As far as I can tell, the choice of spelling an array parameter
> > C or C is entirely cosmetic: both @a and
> > $a are capable of holding an Array reference. Is there actually
> > a difference, e.g. in how they handle an undefined value?
>
Chip Salzenberg wrote:
* As far as I can tell, the choice of spelling an array parameter
C or C is entirely cosmetic: both @a and
$a are capable of holding an Array reference. Is there actually
a difference, e.g. in how they handle an undefined value?
Uhm... It was my impression that one
Chip Salzenberg writes:
> I'm working on enhancing Perl6::Subs[*] to support more parameter
> traits than just C. I have some questions about
> parameters and traits. (These questions all apply to pure Perl 6,
> which I know I won't be able to translate completely, but I want to
> know which targ
I'm working on enhancing Perl6::Subs[*] to support more parameter
traits than just C. I have some questions about
parameters and traits. (These questions all apply to pure Perl 6,
which I know I won't be able to translate completely, but I want to
know which target I'm missing.)
* Given a param
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