Author: lwall Date: 2010-02-24 19:11:54 +0100 (Wed, 24 Feb 2010) New Revision: 29827
Modified: docs/Perl6/Spec/S29-functions.pod Log: [S29] restrict Matcher from taking Bool Modified: docs/Perl6/Spec/S29-functions.pod =================================================================== --- docs/Perl6/Spec/S29-functions.pod 2010-02-24 18:10:51 UTC (rev 29826) +++ docs/Perl6/Spec/S29-functions.pod 2010-02-24 18:11:54 UTC (rev 29827) @@ -20,8 +20,8 @@ Created: 12 Mar 2005 - Last Modified: 2 Feb 2010 - Version: 45 + Last Modified: 24 Feb 2010 + Version: 46 The document is a draft. @@ -117,10 +117,18 @@ =item Matcher - subset Matcher of Object where { $_.can('ACCEPTS') }; + subset Matcher of Mu where none(Bool) Used to supply a test to match against. Assume C<~~> will be used against it. +Booleans are forbidden because they almost always indicate a programming +error where the argument has been evaluated too soon against the wrong C<$_>. +For instance: + grep $_ == 1, 1,2,3; # evaluating wrong $_, so forbidden + grep { $_ == 1 }, 1,2,3; # okay + grep * == 1, 1,2,3; # okay + + =item Ordering subset KeyExtractor of Code where { .signature === :(Any --> Any) }; @@ -1006,4 +1014,4 @@ Please post errors and feedback to perl6-language. If you are making a general laundry list, please separate messages by topic. - +=for vim:set expandtab sw=4: