Re: how typish are roles
HaloO, Jonathan Lang wrote: Larry Wall wrote: But I'm still somewhat set against the notion of using logical ops to do set theory. (Even if you put parens around them.) Understandably so. Perhaps (u) and (n) would be better ASCII equivalents for the union and intersection operators... Hmm, I think using the dualism between set operations and boolean operations is a good thing. Note that there is an isomorphism between , || and ! for the logical side and (), (|) and (!) for sets---DeMorgan etc. We could even introduce low precedence versions (and), (or) and (not). Well, and of course (^) and (xor) corresponding to ^^ and xor. They all form nice mnemonics for each other. Regards, TSa. --
Re: where constraints as roles (was Re: how typish are roles)
HaloO, Jonathan Lang wrote: At its core, a type is nothing more than a constraint on the objects that a given variable is allowed to handle; this would put Cwhere clauses at the center of the type system, with roles coming in a very close second due to the implicit use of .does() in the compact syntax. Great idea! I like the unification of everything typish under the umbrella of (type) constraints. These predicates then need to be amenable to subsumption and entailment forming the dispatch lattice. Of course the sublanguage for where clauses has to be a restricted subset of full Perl 6. Otherwise you can't do machine proofs. This view is shared by mmd-draft.txt, it states that conceptually all dispatch relevant informations are predicates. Hmm, having regular expressions in where clauses already raises the question if one can treat them programatically. E.g. a 'where /^aa.*bb$/' is strictly more specific than 'where /^a.*b$/'. But can that be calculated in a deterministic fashion? Would dispatch at least work on a case by case basis? Or would we get ambiguity errors because of principal incomparability of the two clauses? IOW, I fear this could only be put to work with two subset declarations subset ab of Str where /^a.*b$/; subset aabb of ab where /^aa.*bb$/; and the notion that the second subset by virtue of constraining the possible values further produces a more specific subtype for dispatch. That is nominal subtyping. BTW, the above example is a good case for introducing the subtype relation operator : because we have aabb : ab : Str but do we also have aabb.does(ab) and ab.does(Str)? Could we also state that aabb () ab () Str? Regards, TSa. --
Re: where constraints as roles (was Re: how typish are roles)
TSa wrote: IOW, I fear this could only be put to work with two subset declarations subset ab of Str where /^a.*b$/; subset aabb of ab where /^aa.*bb$/; and the notion that the second subset by virtue of constraining the possible values further produces a more specific subtype for dispatch. That is nominal subtyping. Perl 6 already uses nominal subtyping: S02 - Types are officially compared using name equivalence rather than structural equivalence. There's further elaboration which addresses many of the concerns involved with using nominal subtyping, so I'd suggest reading the section in question before commenting. BTW, the above example is a good case for introducing the subtype relation operator : because we have aabb : ab : Str but do we also have aabb.does(ab) and ab.does(Str)? Could we also state that aabb () ab () Str? Regards, TSa. -- -- Jonathan Dataweaver Lang
beginner's question
Hi, G'day! I am new to the Perl language. As a university student, I want to use perl to build some codes to work as tracing and automatic analysing tool with my data file in Linux environment. Could you kindly teach me which IDE tools should I use (freeware and shareware better :-) ) and what kind of debugger tools should I go through. Any comments are truly appreciated. Thanks in advance! Richard - Do you Yahoo!? Everyone is raving about the all-new Yahoo! Mail.
Re: beginner's question
On Mon, Oct 30, 2006 at 08:09:56AM -0800, Richard Liu wrote: I am new to the Perl language. As a university student, I want to use perl to build some codes to work as tracing and automatic analysing tool with my data file in Linux environment. Could you kindly teach me which IDE tools should I use (freeware and shareware better :-) ) and what kind of debugger tools should I go through. Any comments are truly appreciated. Thanks in advance! Hi Richard! This mailing list is for discussion and development of the Perl6 language. Since this language is still being designed, you probably want to know about Perl5 resources. A good place to start would be http://learn.perl.org/. Also, you might want to try on IRC. There's #perl on the freenode network and #perlhelp on efnet. hope this helps, -Scott -- Jonathan Scott Duff [EMAIL PROTECTED]
[svn:perl6-synopsis] r13350 - doc/trunk/design/syn
Author: larry Date: Mon Oct 30 12:18:19 2006 New Revision: 13350 Modified: doc/trunk/design/syn/S03.pod Log: 1st whack at applying dwimmy hypers to hashes. Modified: doc/trunk/design/syn/S03.pod == --- doc/trunk/design/syn/S03.pod(original) +++ doc/trunk/design/syn/S03.podMon Oct 30 12:18:19 2006 @@ -12,9 +12,9 @@ Maintainer: Larry Wall [EMAIL PROTECTED] Date: 8 Mar 2004 - Last Modified: 16 Oct 2006 + Last Modified: 30 Oct 2006 Number: 3 - Version: 72 + Version: 73 =head1 Changes to Perl 5 operators @@ -877,6 +877,34 @@ Beyond all that, array of scalar types are known at compile time not to need recursive hypers, so the operations can be vectorized aggressively. +Hypers may be applied to hashes as well as to lists. In this case +dwimminess says whether to ignore keys that do not exist +in the other hash, while non-dwimminess says to use all keys that are +in either hash. That is, + +%foo «+» %bar; + +gives you the intersection of the keys, while + +%foo »+« %bar; + +gives you the union of the keys. Asymmetrical hypers are also useful; +for instance, if you say: + +%outer »+» %inner; + +only the %inner keys that already exist in %outer will occur in the result. +Note, however, that you want + +%outer »+=« %inner; + +in order to pass accumulated statistics up a tree, assuming you want %outer +to have the union of keys. + +Unary hash hypers and binary hypers that have only one hash operand +will apply the hyper operator to just the values but return a new +hash value with the same set of keys as the original hash. + =head2 Reduction operators The fourth metaoperator in Perl 6 is the reduction operator. Any
Re: [svn:perl6-synopsis] r13350 - doc/trunk/design/syn
Arguably I've got the dwimminess backwards on this. It seems like %outer «+=» %inner ought to dwim that I want the union of keys. In that view the standard non-dwimmy behavior is to ignore keys that are not in the other hash, and dwimmery consists of using keys even if they aren't in the other hash. On the other hand, it seems odd that the big end of a hyper would imply fewer keys. Obviously it doesn't make much difference whether we write %foo «+=» 1 or %foo »+=» 1 since the key set has to be considered fixed in any event. Well, as usual, I can argue it both ways, and will doubtless flipflop on the issue a couple of times yet... :) Larry
