Re: Which brackets should @a.perl use?
Uri, On Sun, 04 Jan 2009 22:37:43 -0500, Uri Guttman wrote: > that fails with nested arrays. we don't want them to flatten. > > my $c = eval '(1, (4, 5), 3)'; > > will that work as you envision? No, but it's not what I'm proposing. A reference must Perlify as a reference, just as it does today, so that .perl doesn't destroy information by flattening where you don't want it to. Here's what I propose: my @a = 1, 2, 3; @a.perl.say; # (1, 2, 3) my $ra = @a; $ra.perl.say;# [1, 2, 3] my @b = 1, [2, 3], 4; @b.perl.say; # (1, [2, 3], 4) my $rb = @b; $rb.perl.say;# [1, [2, 3], 4] My objection to the current behaviour is that @a and $ra Perlify to the same string -- '[1, 2, 3]' -- losing the information that @a is an array and $ra is a reference to an array. Therefore, if you serialise and unserialise an array, you always get an array of a single element, containing a reference to the real data. What you get back is not what you put in. Markus
Re: reporting bugs
Patrick R. Michaud wrote: On Sun, Jan 04, 2009 at 05:20:56PM +0300, Richard Hainsworth wrote: I posted an email to per6-all asking about how one should go about reporting bugs. That message has appeared on the list. So again: how can bugs be reported? See the "Reporting bugs" section of README file in languages/perl6. (Honestly, I don't know why we call such files "README", since nobody ever does. I think I'll rename the file to "IGNOREME" -- maybe it'll get some attention then. :-) Perhaps modify the Makefile: # targets for building a standalone perl6. # (We're not quite ready to make this a default target.) perl6$(EXE): perl6.pbc $(PBC_TO_EXE) perl6.pbc @echo "$@ built: for more info, or to file bugs, see the README"
Re: Which brackets should @a.perl use?
>> "m" == moritz writes:
>
> m> S02 says:
>
> m> "To get a Perlish representation of any object, use the .perl method.
> Like
> m> the Data::Dumper module in Perl 5, the .perl method will put quotes
> around
> m> strings, square brackets around list values,"
>
> m> So according to this, Rakudo has it right.
> m> But I think that a .perl()ification as ("blue", "light", "hayard",)
> would
> m> make much more sense, because simple thing like
>
> m> @a.push eval(@b.perl)
>
> m> would then DWIM.
>
> for your def of DWIM. i can see wanting an anon array to be pushed onto
> @a building up a structure.
DWIM in the sense that "eval($stuff.perl)" should behave the same as
$stuff itself.
since @a.push(@b) flattens @b into @a, why should I expect something
different from @a.push(eval(@b.perl))?
> your example is too simple to really cover
> this as you could just push @b or a ref to @b (damn, i need to learn
> more basic p6 syntax! :).
If people want @a.push(\...@b) or @a.push([...@b]), they can just write that -
and if the want to use eval + perl, they can include the brackets or
backslash just as well.
> a more useful example would be serializing data trees. if you dump @b
> with .perl do you want the current dumper output of a anon array or your
> list of values? when serializing a tree, you must get the ref version so
> that is the common and default usage. your version isn't DWIMmy there at
> all.
Maybe we can construct something magic with slice context and captures
instead?
Cheers,
Moritz
Re: [perl #61928] [BUG] (undef === undef)
Patrick R. Michaud wrote: > On Fri, Jan 02, 2009 at 01:52:45PM -0800, Todd Hepler wrote: >> I think this is a bug, but I'm not sure. >> >> (undef === undef) currently evaluates to false. Seem like it should be >> true. >> >> I couldn't find a test for it, so below is a patch to add one. > > Before entering a fix for this, I'm curious if (undef =:= undef) > should evaluate to true or false? It should fail, because undef isn't a container, and =:= only operates on containers. Cheers, Moritz
rfc: The values of a junction
I spent a fair amount of time with Rakudo over the holiday break (see
http://dave.whipp.name/sw/perl6 for the writeup). I was generally
impressed with both the language and its implementation. There were,
unsurprisingly, a bunch of things missing. Some of these were things
that are in the spec, but not yet in Rakudo. Others are things that feel
important, but which could be added later, via modules. But one
omission, junctional collapse, appears to me to require core language
support: it is not a feature that can be added as a user module.
The term "collapse" is a metaphor taken from quantum mechanics. It is
apt, because the concept of the "values" of a junction makes sense only
in the context of the action of an operator on the junction. It is my
proposal that we add a new meta-operator to S03 that acts to apply other
operators (equality and inequality tests) to junctions:
@domain |op| $junction --> @values ## junction-collapsing "grep"
@domain !|op| $junction --> @values ## it's negated partner
The operator has the semantics of a "grep", but with the ability to
handle infinite ranges in finite time. The reason for this should become
apparent from a motivating example. Consider a blackjack hand: a set of
cards where the value of aces is either 1 or 11. The total value of a
hand can be described as a junction:
my $ace = 1 | 11;
my $seven = 7;
my @hand = $ace xx 3, $seven;
my $junc_value = [+] @hand; ## any( 10, 20, 30, 40 )
There are a bunch of possible values in the junction. The one we care
about is the largest that is not greater than 21. Using Perl6 as it
stands today, the way to extract this value is brute force:
my $concrete_value = max (0..21).grep: { $^score == $junc_value };
This will work, but doesn't scale. Imagine we wanted all the possible
values, and know nothing about their domain:
my @all_values = (-Inf..Inf).grep: { $^score == $junc_value };
This code has an obvious performance problem that would be tricky to
optimize away! And that problem is the justification of my assertion
that junctional collapse requires core language support. Using a "grep"
meta operator:
my $concrete_value = max 0 .. 21 |==| $junc_value;
my @all_values = -Inf .. Inf |==| $junc_value;
the infinite range can be handled correctly.
Adding a new meta-operator should not be undertaken lightly. I believe
that the collapse of junctions is a necessary feature of the language,
and one that cannot be added as a user-module. Furthermore, alternatives
such as a "eigenvalues" method on the Junction class fail to address the
core property of junctions that their value depends on the operator that
is used to observe them.
Another hurdle that the meta operator must overcome it to demonstrate
that it is sufficiently general. If the only values of "op" was "==",
then we wouldn't need a "meta". Also, the operator has application
beyond collapsing junctions. Some more examples:
say ^Inf |>| one 4 .. Inf; ## result == 5
say @lines |~~| /word/;## no junction: a standard "grep"
An additional feature -- not part of my core proposal, but one that I
think would add value -- would be to allow a typename to be used as the
LHS domain, in place of an infinite range:
say ::Str |eq| any < foo bar baz >; ## match against all strings
say ::Str !|ne| all < foo bar baz >; ## same result
say ::Str !|eq| none < foo bar baz >; ## same again!
or a finite range:
subset BJ_score where { $_ == any 0 .. 21 };
say "score is { max( ::BJ_score |==| $junc_score ) // "bust" }"
I'd like to think that this proposal is an obvious way to meet a
necessary need. Even if this exact approach is not chosen, I hope to
have at least convinced you that core language support is needed to
extract the "values" of a junction; and that a "Junction::eigenvalues"
method is not the correct way to achieve this.
Dave.
ps. The reason for choosing vertical bars, |op|, as the meta-op syntax
is partly by analogy to the concept of "absolute value" that
mathematicians express using vertical bars; and partly a less-cute
distillation of a "bra-ket" suggestion I make in the writeup that I
referenced above.
r24769 - docs/Perl6/Spec
Author: moritz Date: 2009-01-05 17:54:50 +0100 (Mon, 05 Jan 2009) New Revision: 24769 Modified: docs/Perl6/Spec/S29-functions.pod Log: [S29] document isa, can, does, perl and clone Modified: docs/Perl6/Spec/S29-functions.pod === --- docs/Perl6/Spec/S29-functions.pod 2009-01-05 16:53:12 UTC (rev 24768) +++ docs/Perl6/Spec/S29-functions.pod 2009-01-05 16:54:50 UTC (rev 24769) @@ -190,6 +190,22 @@ =head1 Function Packages +=head2 Object + +Every object conforms to the type C. The following methods are thusly +available on every object. + +=over + +=item perl + + our Str multi method perl (Object $o) + +Returns a perlish representation of the object, so that calling C +on the returned string reproduces the object as good as possible. + +=back + =head2 Any The following are defined in the C role: @@ -206,6 +222,27 @@ from C<$by> in that each criterion is applied, in order, until a non-zero (equivalent) result is achieved. +=item can + + our Bool multi method can ($self:, Str $method) + +If there is a multi method of name C<$method> that can be called on +C<$self>, then closure is return has C<$self> bound to the position +of the invocant. + +Otherwise an undefined value is returned. + +=item clone + + our multi method clone (::T $self --> T) + our multi method clone (::T $self, *%attributes --> T) + +The first variant retuns an independent copy of C<$o> that is equivlant +to C<$o>. + +The second variant does the same, but any named arguments override an +attribute during the cloning process. + =item cmp our Order multi sub cmp (Ordering @by, $a, $b) @@ -219,6 +256,19 @@ (tie) result is achieved. If the values are not comparable, returns a proto C object that is undefined. +=item does + + our Bool multi method does ($self:, $type) + +Returns C if and only if C<$self> conforms to type C<$type>. + +=item isa + + our Bool multi method isa ($self:, $type) + +Returns true if a the invocant an instance of class C<$type>, or +of a subset type or a derived class (through inheritance) of C<$type>. + =back =head2 Num
r24768 - docs/Perl6/Spec
Author: particle Date: 2009-01-05 17:53:12 +0100 (Mon, 05 Jan 2009) New Revision: 24768 Modified: docs/Perl6/Spec/S19-commandline.pod Log: [S19] provide rules for negated single-character options; rearrange list items for clarity Modified: docs/Perl6/Spec/S19-commandline.pod === --- docs/Perl6/Spec/S19-commandline.pod 2009-01-05 16:39:14 UTC (rev 24767) +++ docs/Perl6/Spec/S19-commandline.pod 2009-01-05 16:53:12 UTC (rev 24768) @@ -126,12 +126,14 @@ =item * -Option names follow Perl 6 identifier naming convention, but C<'> -is not allowed. +Options may be negated with C, for example C<--/name>, C<:/name>, C<-/n>. +Each single-letter option in a cluster must be negated separately + (e.g. C<-a/n/o> is the same as C<-a -/n -/o>.) =item * -Options may be negated with C, for example C<--/name>, C<:/name>, C<-/n>. +Option names follow Perl 6 identifier naming convention, except C<'> is not +allowed, and single-letter options may be any letter or number. =item *
Re: r24769 - docs/Perl6/Spec
On 2009 Jan 5, at 11:54, pugs-comm...@feather.perl6.nl wrote: + our Str multi method perl (Object $o) + +Returns a perlish representation of the object, so that calling C +on the returned string reproduces the object as good as possible. My inner English teacher cringes in pain. It should be "accurately", or possibly "completely"; "good" just doesn't fit there. -- brandon s. allbery [solaris,freebsd,perl,pugs,haskell] allb...@kf8nh.com system administrator [openafs,heimdal,too many hats] allb...@ece.cmu.edu electrical and computer engineering, carnegie mellon universityKF8NH
Re: rfc: The values of a junction
Em Seg, 2009-01-05 às 07:57 -0800, Dave Whipp escreveu:
>my $ace = 1 | 11;
>my $seven = 7;
>my @hand = $ace xx 3, $seven;
>my $junc_value = [+] @hand; ## any( 10, 20, 30, 40 )
> There are a bunch of possible values in the junction. The one we care
> about is the largest that is not greater than 21. Using Perl6 as it
> stands today, the way to extract this value is brute force:
>my $concrete_value = max (0..21).grep: { $^score == $junc_value };
Well, that considering we don't have any introspection into junctions,
but I think it should be quite straight-forward to make junctions behave
as a list of its members...
my $ace = 1 | 11;
my $seven = 7;
my @hand = $ace xx 3, $seven;
my $junc_value = [+] @hand;
my $concrete_value = max $junc_value.grep: { $^scope < 21 };
daniel
r24774 - docs/Perl6/Spec
Author: particle Date: 2009-01-05 20:29:06 +0100 (Mon, 05 Jan 2009) New Revision: 24774 Modified: docs/Perl6/Spec/S19-commandline.pod Log: [S19] note behavior of clustered options with required values Modified: docs/Perl6/Spec/S19-commandline.pod === --- docs/Perl6/Spec/S19-commandline.pod 2009-01-05 19:21:25 UTC (rev 24773) +++ docs/Perl6/Spec/S19-commandline.pod 2009-01-05 19:29:06 UTC (rev 24774) @@ -14,8 +14,8 @@ Maintainer: Jerry Gay Date: 12 Dec 2008 - Last Modified: 3 Jan 2009 - Version: 9 + Last Modified: 4 Jan 2009 + Version: 10 This is a draft document. This document describes the command line interface. It has changed extensively from previous versions of Perl in order to increase @@ -122,7 +122,9 @@ =item * -Single-letter options may be clustered. C<-ab> means C<-a -b>. +Single-letter options may be clustered. C<-ab> means C<-a -b>. When a +single-letter option which requires a value is clustered, the option may +appear only in the final position of the cluster. =item *
Re: [perl #61920] [PATCH] test division in 02-op-math.t
Kyle Hasselbacher (via RT) wrote: > # New Ticket Created by "Kyle Hasselbacher" > # Please include the string: [perl #61920] > # in the subject line of all future correspondence about this issue. > # http://rt.perl.org/rt3/Ticket/Display.html?id=61920 > > > > I didn't see division in with the other "basic math ops", so... Please note that most tests live in the "official Perl 6 test suite", which lives in t/spec/ in the pugs repository (and is imported into the rakudo working copy if you do 'make spectest'). New tests should go there, so that they can be shared by other implementations. If you want to commit directly to that repository, tell me your desired nickname and email address, so that I can send you a commit bit for the pugs repository. In the mean time I'll try to figure out with your test patches. Cheers, Moritz
Re: [perl #61836] Rakudo cannot take the minimum of undef
Carl MXXsak (via RT) wrote: > # New Ticket Created by "Carl Mäsak" > # Please include the string: [perl #61836] > # in the subject line of all future correspondence about this issue. > # http://rt.perl.org/rt3/Ticket/Display.html?id=61836 > > > > Rakudo r34628: > > $ perl6 -e 'undef min 2' > Multiple Dispatch: No suitable candidate found for 'cmp', with signature > 'PP->I' > [...] Added tests to t/spec/S03-operators/misc.t (but I don't know what the result should be, I just tested with lives_ok). Cheers, Moritz
Re: [perl #61838] Rakudo allows reference to variables before their declaration
Carl MXXsak (via RT) wrote: > # New Ticket Created by "Carl Mäsak" > # Please include the string: [perl #61838] > # in the subject line of all future correspondence about this issue. > # http://rt.perl.org/rt3/Ticket/Display.html?id=61838 > > > > Rakudo r34628: > > $ perl6 -e 'my $a = $b' > Scope not found for PAST::Var '$b' > [...] > > $ perl6 -e 'my $a = $b; my $b' # Compiles and runs! This is actually the first test in t/spec/S04-declarations/my.t (or sufficiently similar). Cheers, Moritz
Parrot Bug Summary
Parrot Bug Summary http://rt.perl.org/rt3/NoAuth/parrot/Overview.html Generated at Mon Jan 5 14:00:01 2009 GMT --- * Numbers * New Issues * Overview of Open Issues * Ticket Status By Version * Requestors with most open tickets --- Numbers Ticket Counts: 29 new + 513 open = 542 Created this week: 4 Closed this week: 13 --- New Issues New issues that have not been responded to yet 1 - 2 weeks old 2 - 3 weeks old 3 - 4 weeks old 4 - 5 weeks old 5 - 6 weeks old 60940 Test failure: t/dynpmc/foo.t 60798 [BUG] [META] Lack of 'To:' header may impede deliverability of email 6 - 7 weeks old 60658 Broken links to Glossary and Patch & Bug Report Submission Information 60652 Lexicals and :outer not Thawed Properly from PBC 60650 Lexical Associations Not Thawed with Tailcalls 7 - 8 weeks old 60578 parrot.org: add link for reporting problems to each page 8 - 9 weeks old 60338 [BUG] NCI segfaults with null pcc_params_signature 9 - 10 weeks old 60206 [BUG] [MMD] Segfault in Lua exception handler 10 - 11 weeks old 11 - 12 weeks old 59978 [TODO] Add SVN revision number of reports to Smolder front page 12 - 13 weeks old 59696 [TODO] Unimplemented Unicode Functions 13 - 14 weeks old 14 - 15 weeks old 15 - 16 weeks old 58990 [TODO] Design new spec coverage mechanism 16 - 17 weeks old 58740 [CAGE] t/configure/*.t and t/steps/*.t: Cleanup test setup/teardown code 17 - 18 weeks old 58672 [TODO] implement method lookup iterators 58488 crashing parrot when calling create_lexinfo 18 - 19 weeks old 19 - 20 weeks old 58324 Build issues on WXP 58188 [TODO] Parrot_find_encoding_converter 58070 [RFC] Disallow .local declarations in long-style call statement 20 - 21 weeks old 58050 Segfault in "make testr" for t/compilers/imcc/syn/hll.t:2 --- Overview of Open Issues PlatformSeverity Tag Lang aix0abandoned 05005threads 0 Amber 0 All1fatal 1bounce0 BASIC 0 bsdos 0High 0Bug 89 bc 0 cygwin 2low 1compiler 0 befunge 0 cygwin_nt 0medium0configure 1 bf 0 darwin 7none 1core 2 cola0 dec_osf0Normal1dailybuild0 forth 0 dgux 0unknown 0docs 3 jako0 dos0Wishlist 3duplicate 0 Lisp0 dynixptx 0 install 2 lolcode 0 freebsd4 library 0 m4 0 generic0 notabug 0 ook 0 gnu0 notok 0 perl6 1 HPUX 0 ok0 plot0 irix 0 Patch26 punie 0 irix64 0 regex 2 pynie 0 Linux 1 sendToCPAN0 python 0 lynxos 0 Todo233 ruby0 mac0 unknown 0 scheme 0 machten0 utilities 0 tcl 0 macos 0 wontfix 0 urm 0 MacOS X7 Zcode 0 mswin324 netbsd 1 next 0 openbsd1 os20 os390 0 other 0 powerux0 qnx0 riscos 0 sco0 Solaris6 sunos 0 svr4 0 svr5 0 sysv 0 unicos 0 unicosmk 0 unix 0 unknown0 uts0 vms0 VOS0 Win32 11 --- Ticket Status By Version New or OpenResolved --- Requestors with most open tickets Paul Cochrane 155 Will Coleda45 chromatic 32 Patrick R. Michaud 29 Jerry Gay 19 Mark Glines15 Reini Urban13 Allison Randal 13 Bernhard Schmalhofer 11 James Keenan 11 --- * Total Issues * New Issues * Overview of Open Issues * Ticket Status By Version * Requestors with most open tickets --- This page is CPU intensive to create, it will be updated
Re: [perl #61840] [TODO] min= and max= operators
Carl MXXsak (via RT) wrote: > # New Ticket Created by "Carl Mäsak" > # Please include the string: [perl #61840] > # in the subject line of all future correspondence about this issue. > # http://rt.perl.org/rt3/Ticket/Display.html?id=61840 > > > > Rakudo r34628 doesn't support the assignment metaoperators C and > C. > > $ perl6 -e 'my $a = 5; $a min= 2; say $a' > get_iter() not implemented in class 'Integer' > [...] Added tests to t/spec/S03-operators/assign.t (which grows to an alarming size...) Cheers, Moritz
r24779 - docs/Perl6/Spec
Author: particle Date: 2009-01-05 21:29:32 +0100 (Mon, 05 Jan 2009) New Revision: 24779 Modified: docs/Perl6/Spec/S06-routines.pod Log: [S06] add another command-line short name example; modify comment to line up visually with others Modified: docs/Perl6/Spec/S06-routines.pod === --- docs/Perl6/Spec/S06-routines.pod2009-01-05 20:25:22 UTC (rev 24778) +++ docs/Perl6/Spec/S06-routines.pod2009-01-05 20:29:32 UTC (rev 24779) @@ -13,9 +13,9 @@ Maintainer: Larry Wall Date: 21 Mar 2003 - Last Modified: 2 Jan 2009 + Last Modified: 4 Jan 2009 Number: 6 - Version: 99 + Version: 100 This document summarizes Apocalypse 6, which covers subroutines and the @@ -2741,6 +2741,7 @@ # Short names -n :name -n=value :name +-nvalue:name # only if not declared Bool -n="spacy value" :name«'spacy value'» -n='spacy value' :name«'spacy value'» -n=val1,'val 2',etc:name«val1 'val 2' etc» @@ -2756,7 +2757,7 @@ --name 'spacy value' :name«'spacy value'» --name=val1,'val 2',etc:name«val1 'val 2' etc» --name val1 'val 2' etc:name«val1 'val 2' etc» # only if declared @ --- # end named argument processing +-- # end named argument processing # Negation --/name:!name
Re: r24769 - docs/Perl6/Spec
On Mon, Jan 05, 2009 at 05:54:50PM +0100, pugs-comm...@feather.perl6.nl wrote: > Author: moritz > Date: 2009-01-05 17:54:50 +0100 (Mon, 05 Jan 2009) > New Revision: 24769 > +=item can > + > + our Bool multi method can ($self:, Str $method) > + > +If there is a multi method of name C<$method> that can be called on > +C<$self>, then closure is return has C<$self> bound to the position > +of the invocant. > + > +Otherwise an undefined value is returned. "then closure is return has" ? perhaps: "then the closure that is returned has" ? If it returns a closure then isn't Bool the signature wrong? Before someone 'fixes' that, though, couldn't can() just return a Bool, and move the 'give me a closure' to another method? Ignoring the performance cost of needlessly creating closures for simple boolean usage, 'can' doesn't seem like a good name for a 'give me a closure' method. > +=item clone > + > + our multi method clone (::T $self --> T) > + our multi method clone (::T $self, *%attributes --> T) > + > +The first variant retuns an independent copy of C<$o> that is equivlant > +to C<$o>. typos "variant returns" and "equivalant" > +The second variant does the same, but any named arguments override an > +attribute during the cloning process. perhaps: "any named arguments are applied to $self as attributes, overriding any attributes with the same names". Makes it clearer that the attributes aren't applied to nested elements. > +=item isa > + > + our Bool multi method isa ($self:, $type) > + > +Returns true if a the invocant an instance of class C<$type>, or typos "Returns C if the invocant is an instance ..." Tim.
[perl #61980] [BUG] French quote hyper operators don't work with -e one liners
# New Ticket Created by Moritz Lenz
# Please include the string: [perl #61980]
# in the subject line of all future correspondence about this issue.
# http://rt.perl.org/rt3/Ticket/Display.html?id=61980 >
Rakudo r34428:
$ echo 'say <1 2> »+« <1 1>' > test.t
$ ./perl6 test.t
23
$ ./perl6 -e 'say <1 2> »+« <1 1>'
Statement not terminated properly at line 1, near
"\x{c2}\x{bb}+\x{c2}\x{ab} <1 1"
current instr.: 'parrot;PGE;Util;die' pc 129
(runtime/parrot/library/PGE/Util.pir:83)
If I introduce a syntax error in the file, the french quotes are reported as
\x{ab} and \x{bb} (without \x{c2}), so I guess that an UTF-8 decoding
step is missing.
Cheers,
Moritz
Re: reporting bugs
Richard Hainsworth wrote: > s/has appeared/has NOT appeared/ > > Richard Hainsworth wrote: >> I posted an email to per6-all asking about how one should go about >> reporting bugs. That message has appeared on the list. >> That's because perl6-all is a meta list, which subscribes you to p6l, p6c and p6u. You still have to send your email to one specific list (for example perl6-compiler would have been the appropriate one). Cheers, Moritz
[perl #61978] [TODO] Rakudo needs a .does method in Object
# New Ticket Created by Moritz Lenz # Please include the string: [perl #61978] # in the subject line of all future correspondence about this issue. # http://rt.perl.org/rt3/Ticket/Display.html?id=61978 > Rakudo r34428: ./perl6 -e '1.does(Int)' Method 'does' not found for invocant of class 'Int' Every object should have .does method, which should check the same type conformance as $object ~~ Type does. There are many tests for .does spread out all over the test suite, many tests for .does and builtin types are in t/spec/S02-builtin_data_types/sigils-and-types.t Cheers, Moritz
[perl #61982] [BUG] is rw/copy traits causes assignment/binding confusion
# New Ticket Created by Moritz Lenz
# Please include the string: [perl #61982]
# in the subject line of all future correspondence about this issue.
# http://rt.perl.org/rt3/Ticket/Display.html?id=61982 >
Rakudo r34428
sub example ($x is rw) {
$x = 3;
my @a;
@a.push($x);
$x = 5;
say @a[0];
}
example(3);
Output is 5, should be 3.
The problem is the same for s/is rw/is copy/
A test for the "is copy" version is in
t/spec/integration/99problems-31-to-40.t
Cheers,
Moritz
Re: returning one or several values from a routine
Daniel Ruoso wrote:
> Hi,
>
> As smop and mildew now support ControlExceptionReturn (see
> v6/mildew/t/return_function.t), an important question raised:
>
> sub plural { return 1,2 }
> sub singular { return 1 }
> my @a = plural();
> my $b = plural();
> my @c = singular();
> my $d = singular();
>
> What should @a, $b, @c and $d contain?
@a = 1, 2;
$b = [1, 2];
@c = 1;
$d = 1;
(According to DWIM semantics and my understanding of the specs)
> Note that the spec says explicitly that a Capture should be returned,
> delaying the context at which the value will be used, this allows
>
> sub named { return :x<1> }
> my $x := |(named);
>
> So, this also means that assigning
>
> my @a = plural();
> my @c = singular();
>
> forces list context in the capture, which should return all positional
> parameters, as expected. But
>
> my $b = plural();
> my $d = singular();
>
> would force item context in the capture, and here is the problem, as a
> capture in item context was supposed to return the invocant.
Maybe we could have a different rule for captures in scalar contexts
that don't have an invocant?
Just my 0.02€,
Moritz
Re: rfc: The values of a junction
That doesn't solve the general problem:
my $junc = any -4 .. Inf;
my @domain = -Inf .. 4;
my @values = @domain |==| $junc;
say @values.perl
>>> [ -4 .. 4 ]
How do you code that using "grep"?
From: Daniel Ruoso
To: Dave Whipp
Cc: perl6-langu...@perl.org
Sent: Monday, January 5, 2009 11:24:29 AM
Subject: Re: rfc: The values of a junction
Em Seg, 2009-01-05 às 07:57 -0800, Dave Whipp escreveu:
>my $ace = 1 | 11;
>my $seven = 7;
>my @hand = $ace xx 3, $seven;
>my $junc_value = [+] @hand; ## any( 10, 20, 30, 40 )
> There are a bunch of possible values in the junction. The one we care
> about is the largest that is not greater than 21. Using Perl6 as it
> stands today, the way to extract this value is brute force:
>my $concrete_value = max (0..21).grep: { $^score == $junc_value };
Well, that considering we don't have any introspection into junctions,
but I think it should be quite straight-forward to make junctions behave
as a list of its members...
my $ace = 1 | 11;
my $seven = 7;
my @hand = $ace xx 3, $seven;
my $junc_value = [+] @hand;
my $concrete_value = max $junc_value.grep: { $^scope < 21 };
daniel
[perl #61990] [BUG] setset .WHAT returns incorrect value
# New Ticket Created by publiustemp-perl6interna...@yahoo.com
# Please include the string: [perl #61990]
# in the subject line of all future correspondence about this issue.
# http://rt.perl.org/rt3/Ticket/Display.html?id=61990 >
For r35004:
subset Even of Int where { not $_ % 2 };
my Even $num = 2;
say $num;
say $num.WHAT;
Output:
2
Int
I'm expecting:
2
Even
Cheers,
Ovid
--
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Re: [perl #61990] [BUG] setset .WHAT returns incorrect value
publiustemp-perl6interna...@yahoo.com (via RT) wrote:
For r35004:
subset Even of Int where { not $_ % 2 };
my Even $num = 2;
say $num;
say $num.WHAT;
Output:
2
Int
I'm expecting:
2
Even
I think the current behaviour is correct (or at least, implemented to
match my understanding of the Perl 6 type system). You're asking for the
type of the value stored in $x, which is an Int.
Even is not a "real type", but rather a refinement type. It is set as a
constraint on what may be held by the container. To get hold of that
(though I don't think we implement any way right now) you probably would
write $x.VAR.type or some such (I'm not sure exactly what the name of
the method on the container that hands this back should be).
Hope this makes sense,
Jonathan
Re: rfc: The values of a junction
Daniel Ruoso wrote:
my $concrete_value = max $junc_value.grep: { $^score < 21 };
In the general case, both the junction and the domain may be infinite:
my @domain = -Inf .. 3;
my $junc = any -4 .. Inf;
my @values = @domain |==| $junc;
say @values.perl
"[-4..3]"
Handling all the variations around this (including compound junctions)
will be quite tricky to implement, even if we did have introspection for
junctions. Certainly not stuff I'd want in typical user-code.
[perl #61988] "$.foo" doesn't accept args
# New Ticket Created by "Dave Whipp"
# Please include the string: [perl #61988]
# in the subject line of all future correspondence about this issue.
# http://rt.perl.org/rt3/Ticket/Display.html?id=61988 >
rakudo: class A { method foo { say @_ }; method bar {
$.foo(42) } }; A.bar
rakudo 35004: OUTPUT«invoke() not implemented in class '
"$.foo(42)" should be synonymous with "self.foo(42)"
also for "$.foo: 42"
Re: returning one or several values from a routine
Daniel Ruoso wrote:
>
> Hi,
>
> As smop and mildew now support ControlExceptionReturn (see
> v6/mildew/t/return_function.t), an important question raised:
>
> sub plural { return 1,2 }
> sub singular { return 1 }
> my @a = plural();
> my $b = plural();
> my @c = singular();
> my $d = singular();
>
> What should @a, $b, @c and $d contain?
>
> Note that the spec says explicitly that a Capture should be returned,
> delaying the context at which the value will be used, this allows
>
> sub named { return :x<1> }
> my $x := |(named);
>
> So, this also means that assigning
>
> my @a = plural();
> my @c = singular();
>
> forces list context in the capture, which should return all positional
> parameters, as expected. But
>
> my $b = plural();
> my $d = singular();
>
> would force item context in the capture, and here is the problem, as a
> capture in item context was supposed to return the invocant.
If item context is supposed to return the invocant, then it would seem
to me that returning a single value from a sub would put that value
into the capture object's invocant. This would mean that the problem
crops up under 'my @c = singular()' instead of 'my $b = plural()'.
The idea in the spec is that the capture object can hold an item, a
distinct list, and a distinct hash all at once. The problem that
we're encountering here is that there are times when the difference
between an item and a one-item list is fuzzy. We _could_ kludge it by
saying that when a sub returns an item $x, it gets returned as a
capture object ($invocant := $x: $param1 := $x) or some such; but this
_is_ a kludge, which has the potential for unexpected and unsightly
developments later on.
Another option would be to change the way that applying item context
to a capture object works in general, to allow for the possibility
that a single-item list was actually intended to be a single item: if
there's no invocant, but there is exactly one positional parameter,
return the positional parameter instead:
$a = |("title": 1)
$b = |("title":)
$c = |(1)
$x = item $a; # $x == "title"
$x = item $b; # $x == "title"
$x = item $c; # $x == 1
$x = list $a; # $x == [1]
$x = list $b; # $x == []
$x = list $c; # $x == [1]
With this approach, return values would return values as positional
parameters unless a conscious effort was made to do otherwise.
But let's say that you really wanted to get the invocant of a capture
object. You can still do so:
|($x:) = $a; # $x == "title"
|($x:) = $b; # $x == "title"
|($x:) = $c; # $x == undef
Likewise, you could specify that you want the first positional
parameter of the capture object by saying:
|($x) = $a; # $x == 1
|($x) = $b; # $x == undef
|($x) = $c; # $x == 1
This isn't as clean as a straight mapping of invocant to item,
positional to list, and named to hash; but I think that it's got
better dwimmery.
--
Jonathan "Dataweaver" Lang
