Author: lwall
Date: 2010-03-03 06:01:30 +0100 (Wed, 03 Mar 2010)
New Revision: 29928
Modified:
docs/Perl6/Spec/S03-operators.pod
Log:
[S03] clarify the way Pair.ACCEPTS uses "so" and "not" semantics
Modified: docs/Perl6/Spec/S03-operators.pod
===================================================================
--- docs/Perl6/Spec/S03-operators.pod 2010-03-03 03:25:06 UTC (rev 29927)
+++ docs/Perl6/Spec/S03-operators.pod 2010-03-03 05:01:30 UTC (rev 29928)
@@ -16,7 +16,7 @@
Created: 8 Mar 2004
Last Modified: 2 Mar 2010
- Version: 195
+ Version: 196
=head1 Overview
@@ -2579,13 +2579,25 @@
is the same as
- if $filename.IO.e { say "exists" }
+ if so $filename.IO.e { say "exists" }
+Likewise
+
+ if $filename.IO ~~ :!e { say "exists" }
+
+is the same as
+
+ if not $filename.IO.e { say "exists" }
+
The 1st form actually translates to the latter form, so the object's
class decides how to dispatch methods. It just happens that the
C<IO> role defaults to the expected filetest semantics, but C<$regex.i> might
-tell you whether the regex is case insensitive, for instance.
+tell you whether the regex is case insensitive, for instance. Likewise,
+you can test anything for definedness or undefinedness:
+ $obj ~~ :defined
+ $obj ~~ :!defined
+
Using the pattern form, multiple tests may be combined via junctions:
given $handle {
@@ -2604,7 +2616,8 @@
when :r & :w & :x
when all(:r,:w,:x)
-The pair forms are useful only for boolean tests, so the
+The pair forms are useful only for boolean tests because the method's
+value is evaluated as a boolen, so the
method form must be used for any numeric-based tests:
if stat($filename).s > 1024 {...}
