HaloO,
just to deepen your understanding of co- and contravariance
you should digest http://www.pps.jussieu.fr/~gc/papers/toplas95.pdf
The important point to get from it is that dispatch-relevant
parameters are also covariant.
Regards, TSa.
--
The unavoidable price of reliability is
HaloO John,
interesting to note that you are now nailing down things that
I'm advocating for quite a while. Are you sure that Perlkind
is following? E.g. $Larry hasn't written 'isa' into S12 yet.
Regards, TSa.
--
The unavoidable price of reliability is simplicity -- C.A.R. Hoare
1 + 2 + 3 + 4
TSa Thomas.Sandlass-at-barco.com |Perl 6| wrote:
HaloO,
just to deepen your understanding of co- and contravariance
you should digest http://www.pps.jussieu.fr/~gc/papers/toplas95.pdf
The important point to get from it is that dispatch-relevant
parameters are also covariant.
Regards, TSa.
TSa Thomas.Sandlass-at-barco.com |Perl 6| wrote:
HaloO John,
interesting to note that you are now nailing down things that
I'm advocating for quite a while. Are you sure that Perlkind
is following? E.g. $Larry hasn't written 'isa' into S12 yet.
Regards, TSa.
I am listening. I'm synthesizing
HaloO,
John M. Dlugosz wrote:
isa as a synonym for is that turns on warnings is documented at the
end of my paper under Concepts discussed in this paper that are not on
the Synopses.
I totally agree! Using 'isa' pulls in the type checker. Do we have the
same option for 'does' e.g. 'doesa'?
Daniel Ruoso daniel-at-ruoso.com |Perl 6| wrote:
Very interesting reading... :)
It actually made me think that it would be possible to implement it as a
pragma.
class A { has $.a };
class B { has $.b };
sub foo { A $a } { ... } [sic, should be () around parameters]
{
HaloO,
Daniel Ruoso wrote:
[ I'm using this message to reply, because I didn't receive your
reply... I'm taking it from the list history... There really seems to be
something wrong with this list... ]
I see all your messages arrive twice.
This is not specced apparently to leave room for
--- John M. Dlugosz [EMAIL PROTECTED] wrote:
isa as a synonym for is that turns on warnings is documented at
the end of my paper under Concepts discussed in this paper that are
not on
the Synopses. Nobody's objected to it. In this group, I'm
preaching to the choir anyway.
So, isn't isa
HaloO,
Ovid wrote:
So, isn't isa and the £ merely things which can be added by
programmers by changing the grammar? That was one of the design goals
of the language.
With a changeable grammar this applies to everything except the
changeability itself. But the type system is part of the
HaloO,
John M. Dlugosz wrote:
TSa Thomas.Sandlass-at-barco.com |Perl 6| wrote:
multi infix:= (Any $lhs, A $rhs)
{
$lhs.STORE($rhs.clone); # or .cow if that's not automatic
}
$lhs.VAR.STORE.
I guess I also forgot the is rw to get a binding to the caller's
container not
Ter, 2008-04-29 às 21:03 -0500, John M. Dlugosz escreveu:
In response to questions on my whitepaper, I made this companion
to bring people up to speed on the issue.
http://www.dlugosz.com/Perl6/web/isa-inheritance.html
Very interesting reading... :)
It actually made me think that it would be
Qua, 2008-04-30 às 15:55 +0200, TSa escreveu:
But the type system is part of the language core.
As such 'isa' and 'like' or assignment and binding semantics
need a definition.
Actually, this is one of the hardest parts of implementing Perl 6,
because even 'isa', 'like', assignment and binding
--- chromatic [EMAIL PROTECTED] wrote:
$p1 must be like a Point, but it needn't actually
be a Point. Both $p2 and the return value must be the same type of
thing that $p1 is.
That was always my goal for roles in the first place. I'll be a
little sad if
Perl 6 requires an explicit
TSa Thomas.Sandlass-at-barco.com |Perl 6| wrote:
HaloO,
John M. Dlugosz wrote:
isa as a synonym for is that turns on warnings is documented at
the end of my paper under Concepts discussed in this paper that are
not on the Synopses.
I totally agree! Using 'isa' pulls in the type checker. Do
Ovid publiustemp-perl6language2-at-yahoo.com |Perl 6| wrote:
So, isn't isa and the £ merely things which can be added by
programmers by changing the grammar? That was one of the design goals
of the language.
The capability needs to exist as part of the overall type system, with
primitive
TSa Thomas.Sandlass-at-barco.com |Perl 6| wrote:
Finally combine that with the wish to allow literals of class A. Let's
assume the grammar is patched to parse integer literals as As. Then
with the above 7.inc gives an error because 7 is not mutable. So as
I outlined before I want to care for
On Apr 30, 2008, at 8:43 AM, TSa wrote:
John M. Dlugosz wrote:
isa as a synonym for is that turns on warnings is documented at
the end of my paper under Concepts discussed in this paper that
are not on the Synopses.
I totally agree! Using 'isa' pulls in the type checker. Do we have the
On Wed, Apr 30, 2008 at 07:29:58AM -0500, John M. Dlugosz wrote:
I am listening. I'm synthesizing and documenting. I'm also disappointed
with the lack of feedback from Larry, considering the amount of effort and
time I'm putting into it. But I'm sure he'll squawk if I say something
Qua, 2008-04-30 às 08:56 -0700, Ovid escreveu:
I had initially thought this, but think about the case where someone
wants to rewrite something to be compliant to another interface. If I
pass a CGI::Simple object to a method expecting a CGI object, there's
an excellent chance that it will
Brandon S. Allbery KF8NH wrote:
TSa wrote:
I totally agree! Using 'isa' pulls in the type checker. Do we have the
same option for 'does' e.g. 'doesa'? Or is type checking always implied
in role composition? Note that the class can override a role's methods
at will.
It occurs to me that
On Wed, Apr 30, 2008 at 9:14 PM, Jon Lang [EMAIL PROTECTED] wrote:
Brandon S. Allbery KF8NH wrote:
TSa wrote:
I totally agree! Using 'isa' pulls in the type checker. Do we have the
same option for 'does' e.g. 'doesa'? Or is type checking always implied
in role composition? Note
On Apr 30, 2008, at 15:14 , Jon Lang wrote:
Brandon S. Allbery KF8NH wrote:
It occurs to me that this shouldn't be new keywords, but adverbs,
i.e. ``is
:strict Dog''.
On a side note, I'd like to make a request of the Perl 6 community
with regard to coding style: could we please have
On Apr 30, 2008, at 15:14 , Jon Lang wrote:
only is is :strictly Dog more legible, but it leaves room for the
possible future inclusion of adjective-based syntax such as big Dog
It occurs to me that we already have this: we call them types.
--
brandon s. allbery
Larry Wall larry-at-wall.org |Perl 6| wrote:
On a more fundamental level, I wonder what the social ramifications
are. First, to what extent is this something that will interfere
with people who don't want to learn higher-order typing in order
to get their job done, but will be forced to because
Daniel Ruoso daniel-at-ruoso.com |Perl 6| wrote:
Qua, 2008-04-30 às 08:56 -0700, Ovid escreveu:
I had initially thought this, but think about the case where someone
wants to rewrite something to be compliant to another interface. If I
pass a CGI::Simple object to a method expecting a CGI
Larry Wall larry-at-wall.org |Perl 6| wrote:
I don't like using ::?CLASS for something that is not a compile-time
constant. ... we don't use ::?SELF anymore, but self, because that can vary in
meaning dynamically
OK, for some meaning of constant. After all ::?LINE is different every time you
John M. Dlugosz wrote:
And you can use CLASS in a role also, confidant that it will be looked up
according to the normal rules when the class is composed using that role,
just like any other symbol that is not found when the role is defined.
Using ::?CLASS in a role is an error (unless you
On Wednesday 30 April 2008 08:56:24 Ovid wrote:
That was always my goal for roles in the first place. I'll be a
little sad if Perl 6 requires an explicit notation to behave correctly
here -- that is, if the default check is for subtyping, not polymorphic
equivalence.
I had initially
On May 1, 2008, at 0:53 , chromatic wrote:
correctness sense. Sadly, both trees and dogs bark.)
Hm, no. One's a noun, the other's a verb. Given the linguistic
orientation of Perl6, it seems a bit strange that the syntax for both
is the same: while accessors and mutators are
On Wed, Apr 30, 2008 at 9:58 PM, Brandon S. Allbery KF8NH
[EMAIL PROTECTED] wrote:
On May 1, 2008, at 0:53 , chromatic wrote:
correctness sense. Sadly, both trees and dogs bark.)
Hm, no. One's a noun, the other's a verb. Given the linguistic
orientation of Perl6, it seems a bit
On May 1, 2008, at 1:30 , Jon Lang wrote:
On Wed, Apr 30, 2008 at 9:58 PM, Brandon S. Allbery KF8NH
[EMAIL PROTECTED] wrote:
On May 1, 2008, at 0:53 , chromatic wrote:
correctness sense. Sadly, both trees and dogs bark.)
Hm, no. One's a noun, the other's a verb. Given the
On Thu, May 01, 2008 at 01:34:45AM -0400, Brandon S. Allbery KF8NH wrote:
On May 1, 2008, at 1:30 , Jon Lang wrote:
In defense of chromatic's point, both people and syrup run.
But there *is* some commonality there, to the extent that both are motion.
This is the kind of thing that spawned
On May 1, 2008, at 1:46 , Larry Wall wrote:
On Thu, May 01, 2008 at 01:34:45AM -0400, Brandon S. Allbery KF8NH
wrote:
On May 1, 2008, at 1:30 , Jon Lang wrote:
In defense of chromatic's point, both people and syrup run.
But there *is* some commonality there, to the extent that both are
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