Author: lwall
Date: 2010-03-30 20:22:09 +0200 (Tue, 30 Mar 2010)
New Revision: 30242
Modified:
docs/Perl6/Spec/S02-bits.pod
docs/Perl6/Spec/S09-data.pod
Log:
[S02,S09] capitalize Junction again
conjecture a junction-like Each type
Modified: docs/Perl6/Spec/S02-bits.pod
===================================================================
--- docs/Perl6/Spec/S02-bits.pod 2010-03-30 18:11:56 UTC (rev 30241)
+++ docs/Perl6/Spec/S02-bits.pod 2010-03-30 18:22:09 UTC (rev 30242)
@@ -13,8 +13,8 @@
Created: 10 Aug 2004
- Last Modified: 26 Mar 2010
- Version: 209
+ Last Modified: 30 Mar 2010
+ Version: 210
This document summarizes Apocalypse 2, which covers small-scale
lexical items and typological issues. (These Synopses also contain
@@ -573,11 +573,6 @@
repeated autoboxing can slow your program more than the native type
can speed it up.)
-The C<junction> type is considered a native type because its internal
-representation is fixed, and you may not usefully derive from it
-because the intent of junctions is to autothread any method calls
-on them.
-
Some object types can behave as value types. Every object can produce
a "WHICH" value that uniquely identifies the
object for hashing and other value-based comparisons. Normal objects
@@ -1156,7 +1151,7 @@
automatically declaring a undefined prototype value with the same name, known
as the I<type object>. The name itself returns that type object:
- Mu Perl 6 object (default block parameter type, either Any or
junction)
+ Mu Perl 6 object (default block parameter type, Any, Junction, or
Each)
Any Perl 6 object (default routine parameter type, excludes
junction)
Cool Perl 6 Convenient OO Loopbacks
Whatever Wildcard (like Any, but subject to do-what-I-mean via MMD)
@@ -1173,7 +1168,7 @@
on the type specified by the container but continues to carry the
C<Failure> role. Use C<fail> to return specific failures. Use C<Mu>
for the most generic non-failure undefined value. The C<Any> type,
-derived from C<Mu>, is also undefined, but excludes C<junctions> so
+derived from C<Mu>, is also undefined, but excludes C<Junction> and C<Each>
types so
that autothreading may be dispatched using normal multiple dispatch
rules. All user-defined classes derive from the C<Any> class by default.
The C<Whatever> type is derived from C<Any> but nothing else
Modified: docs/Perl6/Spec/S09-data.pod
===================================================================
--- docs/Perl6/Spec/S09-data.pod 2010-03-30 18:11:56 UTC (rev 30241)
+++ docs/Perl6/Spec/S09-data.pod 2010-03-30 18:22:09 UTC (rev 30242)
@@ -13,8 +13,8 @@
Created: 13 Sep 2004
- Last Modified: 4 Mar 2010
- Version: 44
+ Last Modified: 30 Mar 2010
+ Version: 45
=head1 Overview
@@ -944,8 +944,10 @@
Perl 6's GC approach, as long as PDL's objects are registered with Parrot
correctly.)
-=head1 Junctions
+=head1 Autothreading types
+=head2 Junctions
+
A junction is a superposition of data values pretending to be a single
data value. Junctions come in four varieties:
@@ -980,9 +982,10 @@
In particular, if a junction is used as an argument to any routine
(operator, closure, method, etc.), and the scalar parameter you
are attempting to bind the argument to is inconsistent with the
-C<junction> type, that routine is "autothreaded", meaning the routine
+C<Junction> type, that routine is "autothreaded", meaning the routine
will be called automatically as many times as necessary to process
the individual scalar elements of the junction in parallel.
+(C<Each> types are also autothreaded, but are serial and lazy in nature.)
The results of these separate calls are then recombined into a
single junction of the same species as the junctive argument.
@@ -1054,17 +1057,16 @@
please limit use of junctions to situations where the eventual binding
to a scalar formal parameter is clear.
-(Conjucture: in post-Perl 6.0.0 we might introduce an C<each()>
-junction which keeps track of its initial values, returning on collapse
-those initial values which transformed into a true value, for example
+=head2 Each
- each(2, 3, 4) - 3
+[This section is considered conjectural.]
-would return an unordered collection consisting of 2 and 4, because
-C<2-3> and C<4-3> are True in boolean context, while C<3-3> is False.
-However it is not yet clear if we really want that, and if yes, in which
-context the collapse will occur).
+An C<Each> type autothreads like a junction, but does so serially and lazily,
+and is used only for its mapping capabilities. The prototypical use
+case is where a hyperoperator would parallelize in an unfortunate way:
+ @array».say # order not guaranteed
+ @array.each.say # order guaranteed
=head1 Parallelized parameters and autothreading
