Author: larry
Date: Wed Jan 17 11:50:09 2007
New Revision: 13527
Modified:
doc/trunk/design/syn/S03.pod
Log:
Revised reduce semantics to allow list infixes to work correctly.
Modified: doc/trunk/design/syn/S03.pod
==============================================================================
--- doc/trunk/design/syn/S03.pod (original)
+++ doc/trunk/design/syn/S03.pod Wed Jan 17 11:50:09 2007
@@ -12,9 +12,9 @@
Maintainer: Larry Wall <[EMAIL PROTECTED]>
Date: 8 Mar 2004
- Last Modified: 8 Jan 2007
+ Last Modified: 17 Jan 2007
Number: 3
- Version: 88
+ Version: 89
=head1 Changes to Perl 5 operators
@@ -1373,8 +1373,17 @@
(And, in fact, the latter are already easy to express anyway,
and more obviously nonsensical.)
-A reduce operator returns only a scalar result regardless of context.
-To return all intermediate results, backslash the operator:
+Most reduce operators return a simple scalar value, and hence do not care
+whether they are evaluated in item or list context. However, as with
+other list operators and functions, a reduce operator may return a list
+that will automatically be interpolated into list context, so you may
+use it on infix operators that operate over lists as well as scalars:
+
+ my ($min, $max) = [minmax] @minmaxpairs;
+
+A variant of the reduction metaoperator is pretty much guaranteed
+to produce a list; to lazily generate all intermediate results along
+with the final result, you can backslash the operator:
say [\+] 1..* # (1, 3, 6, 10, 15, ...)
@@ -1990,7 +1999,7 @@
!!! ... ???
[+] [*] [<] [\+] [\*] etc.
(also = as list assignment)
- list infix ¥ <== ==> X XX X~X X*X XeqvX etc.
+ list infix ¥ <== ==> minmax X XX X~X X*X XeqvX etc.
loose and and
loose or or xor err
expr terminator ; {} as control block, statement modifiers
