Re: some questions about S02(type)
On Fri, Apr 3, 2009 at 10:52 PM, Moritz Lenz wrote:
> Xiao Yafeng wrote:
> > 1. Could I set multi-return type?like
> > sub test as (Int, Str) {...}
>
> "as" is coercion - so to what would it coerce? Int or Str? How could the
> compiler know? Or do you mean something like a tuple?
>
as what Timothy S. Nelson say
>
> > 2. set is unordered collection of values， subset is new type. People are
> > apt to confuse the two concepts.
>
> Note that people never write "subset" in their code, the write things like
> sub f($x where { ... } ) and the "where" constructs the subset type. I
> don' think that's
>
I think subset can define a new type, I'm custom to set it at
head of code,
subset name_string of Str where {~~/^^name/};
am I wrong?
>
> > 3. Could I define primary key for a bag variable?
>
> All items in a Bag are "primary keys", but there's no data additional
> data associated with it.
>
I mean whether I can see Set as a table and Bag as a table with a
unique constraint? like:
subset test of Bag(test_name Str, test_ID Int, primary key(test_ID))
Multi-Dimensional arrays
Am I right that multi-dimensional arrays do not yet work fully in Rakudo?
Re: some questions about S02(type)
On Sat, 4 Apr 2009, Xiao Yafeng wrote: 3. Could I define primary key for a bag variable? All items in a Bag are "primary keys", but there's no data additional data associated with it. I mean whether I can see Set as a table and Bag as a table with a unique constraint? like: subset test of Bag(test_name Str, test_ID Int, primary key(test_ID)) I don't think you can really do something like that. Perl 6 as specified leaves many things up to libraries. Implementing a Table type will no doubt be one of those things. I would like to have a Table type that will work well with the Tree/Plex type that I am working on. In the meantime, a table would need to be represented as an array of hashes, or a hash of arrays. HTH, - | Name: Tim Nelson | Because the Creator is,| | E-mail: wayl...@wayland.id.au| I am | - BEGIN GEEK CODE BLOCK Version 3.12 GCS d+++ s+: a- C++$ U+++$ P+++$ L+++ E- W+ N+ w--- V- PE(+) Y+>++ PGP->+++ R(+) !tv b++ DI D G+ e++> h! y- -END GEEK CODE BLOCK-
r26069 - docs/Perl6/Spec
Author: masak
Date: 2009-04-04 11:32:02 +0200 (Sat, 04 Apr 2009)
New Revision: 26069
Modified:
docs/Perl6/Spec/S09-data.pod
Log:
[S09] added table of operations that autovivify
Modified: docs/Perl6/Spec/S09-data.pod
===
--- docs/Perl6/Spec/S09-data.pod2009-04-04 04:48:37 UTC (rev 26068)
+++ docs/Perl6/Spec/S09-data.pod2009-04-04 09:32:02 UTC (rev 26069)
@@ -1230,6 +1230,19 @@
autovivification is defined in terms of protoobjects rather than failure,
it still works under "use fatal".
+This table solidifies the intuition that an operation pertaining to some data
+structure causes the protoobject to autivivify to such an object:
+
+operationautovivifies to
+====
+push, unshift, .[] Array
+.{}, .<> Hash
+
+In addition to the above data structures autovivifying, C<++> and C<--> will
+cause an C to appear, C<~=> will create a C etc; but these are
+natural consequences of the operators working on C, qualitatively
+different from autovivifying containers.
+
The type of the protoobject returned by a non-successful lookup should
be identical to the type that would be returned for a successful lookup.
Re: Multi-Dimensional arrays
Peter (>): > Am I right that multi-dimensional arrays do not yet work fully in Rakudo? Yes, you are. That is to say, you can't do this yet: my @a[4;2]; # Valid indices are 0..3 ; 0..1 There's nothing stopping you from creating an array of arrays, though. // Carl
r26081 - docs/Perl6/Spec
Author: masak
Date: 2009-04-04 14:57:29 +0200 (Sat, 04 Apr 2009)
New Revision: 26081
Modified:
docs/Perl6/Spec/S09-data.pod
Log:
[S09] removed .<> from the table
It's just sugar anyway. pmurias++ for pointing that out.
Modified: docs/Perl6/Spec/S09-data.pod
===
--- docs/Perl6/Spec/S09-data.pod2009-04-04 11:09:55 UTC (rev 26080)
+++ docs/Perl6/Spec/S09-data.pod2009-04-04 12:57:29 UTC (rev 26081)
@@ -1236,7 +1236,7 @@
operationautovivifies to
====
push, unshift, .[] Array
-.{}, .<> Hash
+.{} Hash
In addition to the above data structures autovivifying, C<++> and C<--> will
cause an C to appear, C<~=> will create a C etc; but these are
r26090 - docs/Perl6/Spec
Author: s1n
Date: 2009-04-04 20:45:14 +0200 (Sat, 04 Apr 2009)
New Revision: 26090
Modified:
docs/Perl6/Spec/S16-io.pod
Log:
[spec] minor touch-ups to better format the pod for perl5's perldoc tool.
Modified: docs/Perl6/Spec/S16-io.pod
===
--- docs/Perl6/Spec/S16-io.pod 2009-04-04 15:57:31 UTC (rev 26089)
+++ docs/Perl6/Spec/S16-io.pod 2009-04-04 18:45:14 UTC (rev 26090)
@@ -1,4 +1,3 @@
-
=encoding utf8
=head1 Title
@@ -62,8 +61,8 @@
syntax:
{
- temp $*OUT = open $newfile, :w;
- foo() # all stdout goes to $newfile
+temp $*OUT = open $newfile, :w;
+foo() # all stdout goes to $newfile
}
# stdout reverts to outer scope's definition
@@ -77,21 +76,23 @@
=head2 User role
-role User {
- has $username; # Username (some descendants(?) may want to implement a
real $name)
- has $id; # User ID
- has $dir; # Home directory for files
-}
+role User {
+has $username; # Username (some descendants(?) may want to implement a
real $name)
+has $id; # User ID
+has $dir; # Home directory for files
+}
+=over
+
=item new
- method User new($Username?, $UID?) {...}
+method User new($Username?, $UID?) {...}
Creates a new User object, fetching the information either by username or user
ID.
=item write
- method write() {...}
+method write() {...}
Tries to write the current User object to the user database. This may well
fail.
@@ -103,50 +104,56 @@
When converted to a Num, returns $uid.
+=back
+
=head2 OS::Unix::User role
-role OS::Unix::User does User {
- has $password;
- has $gid;
- has $gecos;
- has $shell;
-}
+role OS::Unix::User does User {
+has $password;
+has $gid;
+has $gecos;
+has $shell;
+}
All the information is naturally fetched from the system via getpwuid,
getpwnam, or the
like.
=head2 Group role
-role Group {
- has $name;
- has $id;
- has @members;
-}
+role Group {
+has $name;
+has $id;
+has @members;
+}
+=over
+
=item new
- method Group new(:$Name, :$ID);
+method Group new(:$Name, :$ID);
=item write
- method write();
+method write();
Tries to write the group entry into the system group database.
-=head OS::Unix::NameServices role
+=back
+=head2 OS::Unix::NameServices role
+
The NameServices role has a bunch of functions that between them will return
the whole
Name Services database between them, as lists of objects. The lists are
specifically
intended to be lazy.
-role NameServices {
- method List of User users() {...} # getpwent, setpwent, endpwent
- method List of Groupgroups(){...} # getgrent, setgrent, endgrent
- method List of Service services() {...} # getservent, setservent,
endservent
- method List of Protocol protocols() {...} # getprotoent, setprotoent,
endprotoent
- method List of Network networks() {...} # getnetent, setnetent,
endnetent
- method List of Host hosts() {...} # gethostent, sethostent,
endhostent
-}
+role NameServices {
+method List of User users() {...} # getpwent, setpwent,
endpwent
+method List of Groupgroups(){...} # getgrent, setgrent,
endgrent
+method List of Service services() {...} # getservent, setservent,
endservent
+method List of Protocol protocols() {...} # getprotoent, setprotoent,
endprotoent
+method List of Network networks() {...} # getnetent, setnetent,
endnetent
+method List of Host hosts() {...} # gethostent, sethostent,
endhostent
+}
=head1 Additions
@@ -155,5 +162,4 @@
=cut
-=encoding utf8
-
+=for vim:set expandtab sw=4:
Re: some questions about S02(type)
Timothy S. Nelson wrote: On Sat, 4 Apr 2009, Xiao Yafeng wrote: I mean whether I can see Set as a table and Bag as a table with a unique constraint? like: I think you have that backwards. A Set is conceptually like a Bag with a uniqueness constraint, not the other way around. subset test of Bag(test_name Str, test_ID Int, primary key(test_ID)) I don't think you can really do something like that. Perl 6 as specified leaves many things up to libraries. Implementing a Table type will no doubt be one of those things. I would like to have a Table type that will work well with the Tree/Plex type that I am working on. In the meantime, a table would need to be represented as an array of hashes, or a hash of arrays. Speaking of libraries, I already implemented a table type ... it's called Set::Relation/::V2 and its on CPAN right now ... for Perl 5 ... I still have to port it to Perl 6, unless someone else wants to do that, but I designed it so that would be easy to do. The port could stand for some additional Perl 6 savvyness too. -- Darren Duncan
