Author: larry
Date: Fri Sep 15 08:38:58 2006
New Revision: 12006
Modified:
doc/trunk/design/syn/S04.pod
Log:
smartlinkable discussion of bindables on while and repeat while
Modified: doc/trunk/design/syn/S04.pod
==============================================================================
--- doc/trunk/design/syn/S04.pod (original)
+++ doc/trunk/design/syn/S04.pod Fri Sep 15 08:38:58 2006
@@ -12,9 +12,9 @@
Maintainer: Larry Wall <[EMAIL PROTECTED]>
Date: 19 Aug 2004
- Last Modified: 1 Sep 2006
+ Last Modified: 15 Sep 2006
Number: 4
- Version: 38
+ Version: 39
This document summarizes Apocalypse 4, which covers the block and
statement syntax of Perl.
@@ -190,6 +190,20 @@
...
}
+You may optionally bind the result of the conditional expression to a
+parameter of the block:
+
+ while something() -> $thing {
+ ...
+ }
+
+Nothing is ever bound implicitly, however, and many conditionals would
+simply bind True or False in an uninteresting fashion. This mechanism
+is really only good for objects that know how to return a boolean
+value and still remain themselves. In general, for most iterated
+solutions you should consider using a C<for> loop instead (see below).
+In particular, we now generally use C<for> to iterate filehandles.
+
=head2 The C<repeat> statement
Unlike in Perl 5, applying a statement modifier to a C<do> block is
@@ -242,6 +256,22 @@
...
}
+As with an ordinary C<while>, you may optionally bind the result of
+the conditional expression to a parameter of the block:
+
+ repeat -> $thing {
+ ...
+ } while something();
+
+or
+
+ repeat while something() -> $thing {
+ ...
+ }
+
+Since the loop executes once before evaluating the condition, the
+bound parameter will be undefined that first time through the loop,
+
=head2 The general loop statement
The C<loop> statement is the C-style C<for> loop in disguise:
