Author: larry Date: Wed Mar 28 13:17:43 2007 New Revision: 14357 Modified: doc/trunk/design/syn/S04.pod
Log: Tweaked when/break to leave innermost block with formal $_ (also TheDamian++) Modified: doc/trunk/design/syn/S04.pod ============================================================================== --- doc/trunk/design/syn/S04.pod (original) +++ doc/trunk/design/syn/S04.pod Wed Mar 28 13:17:43 2007 @@ -14,7 +14,7 @@ Date: 19 Aug 2004 Last Modified: 28 Mar 2007 Number: 4 - Version: 55 + Version: 56 This document summarizes Apocalypse 4, which covers the block and statement syntax of Perl. @@ -573,12 +573,14 @@ the block, not by the nature of the block itself. A C<when> statement implicitly does a "smart match" between the current topic (C<$_>) and the argument of the C<when>. If the smart match succeeds, C<when>'s -associated block is executed, and the immediatly surrounding block -is automatically broken out of. (If that is not the block you wish -to leave, you must use the C<LABEL.leave> method to be more specific, -since the compiler may find it difficult to guess which surrounding -construct last set C<$_> as the topic.) The value of the inner block -is returned as the value of the outer block. +associated block is executed, and the innermost surrounding block +that has C<$_> as one of its formal parameters (either explicit +or implicit) is automatically broken out of. (If that is not the +block you wish to leave, you must use the C<LABEL.leave> method to +be more specific, since the compiler may find it difficult to guess +which surrounding construct was intended as the actual topicalizer.) +The value of the inner block is returned as the value of the outer +block. If the smart match fails, control passes to the next statement normally, which may or may not be a C<when> statement. Since C<when> @@ -605,8 +607,12 @@ explicitly or implicitly), that parameter can function as the topic of any C<when> statements within the loop. -You can explicitly break out of a C<when> block (and its surrounding -block) early using the C<break> verb. You can explicitly break out +You can explicitly break out of a C<when> block (and its surrounding topicalizer +block) early using the C<break> verb. More precidely, it leaves the +innermost block outside the C<when> that uses C<$_> as one of its formal +parameters, either explicitly or implicitly. + +You can explicitly break out of a C<when> block and go to the next statement by using C<continue>. (Note that, unlike C's idea of falling through, subsequent C<when> conditions are evaluated. To jump into the next C<when> block you
