X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=pod%2Fperlsub.pod;h=74d0b1ac26fed091d13a05a0fbfd40c241606d29;hb=3c4fb04a912b266806354630dd98a7e36a830fbe;hp=4c7dcd620914c0309652aab7790ce140f6eac290;hpb=d822fdf9523774354b4abafec1aa0c8639788575;p=p5sagit%2Fp5-mst-13.2.git

diff --git a/pod/perlsub.pod b/pod/perlsub.pod
index 4c7dcd6..74d0b1a 100644
--- a/pod/perlsub.pod
+++ b/pod/perlsub.pod
@@ -227,10 +227,10 @@ indirectly by the run-time system itself, usually due to a triggered event.
 Subroutines that do special, pre-defined things include C<AUTOLOAD>, C<CLONE>,
 C<DESTROY> plus all functions mentioned in L<perltie> and L<PerlIO::via>.
 
-The C<BEGIN>, C<CHECK>, C<INIT> and C<END> subroutines are not so much
-subroutines as named special code blocks, of which you can have more
-than one in a package, and which you can B<not> call explicitly.  See
-L<perlmod/"BEGIN, CHECK, INIT and END">
+The C<BEGIN>, C<UNITCHECK>, C<CHECK>, C<INIT> and C<END> subroutines
+are not so much subroutines as named special code blocks, of which you
+can have more than one in a package, and which you can B<not> call
+explicitly.  See L<perlmod/"BEGIN, UNITCHECK, CHECK, INIT and END">
 
 =head2 Private Variables via my()
 X<my> X<variable, lexical> X<lexical> X<lexical variable> X<scope, lexical>
@@ -453,26 +453,10 @@ each time the gimme_another() function is called:
 Also, since C<$x> is lexical, it can't be reached or modified by any Perl
 code outside.
 
-You can initialize state variables, and the assigment will be executed
-only once:
-
-    sub starts_from_42 { state $x = 42; return ++$x }
-
-You can also, as a syntactic shortcut, initialize more than one if they're
-all declared within the same state() clause:
-
-    state ($a, $b, $c) = ( 'one', 'two', 'three' );
-
-However, be warned that state variables declared as part of a list will
-get assigned each time the statement will be executed, since it will be
-considered as a regular list assigment, not one to be executed only once:
-
-    (state $x, my $y) = (1, 2); # $x gets reinitialized every time !
-
-B<Caveat>: the code at the right side of the assignment to a state
-variable will be executed every time; only the assignment is disabled. So,
-avoid code that has side-effects, or that is slow to execute. This might
-be optimized out in a future version of Perl.
+When combined with variable declaration, simple scalar assignment to C<state>
+variables (as in C<state $x = 42>) is executed only the first time.  When such
+statements are evaluated subsequent times, the assignment is ignored.  The
+behavior of this sort of assignment to non-scalar variables is undefined.
 
 =head3 Persistent variables with closures
 
@@ -521,8 +505,9 @@ starts to run:
 	}
     }
 
-See L<perlmod/"BEGIN, CHECK, INIT and END"> about the
-special triggered code blocks, C<BEGIN>, C<CHECK>, C<INIT> and C<END>.
+See L<perlmod/"BEGIN, UNITCHECK, CHECK, INIT and END"> about the
+special triggered code blocks, C<BEGIN>, C<UNITCHECK>, C<CHECK>,
+C<INIT> and C<END>.
 
 If declared at the outermost scope (the file scope), then lexicals
 work somewhat like C's file statics.  They are available to all
@@ -1049,7 +1034,7 @@ corresponding built-in.
     sub myreverse (@)	     myreverse $a, $b, $c
     sub myjoin ($@)	     myjoin ":", $a, $b, $c
     sub mypop (\@)	     mypop @array
-    sub mysplice (\@$$@)     mysplice @array, @array, 0, @pushme
+    sub mysplice (\@$$@)     mysplice @array, 0, 2, @pushme
     sub mykeys (\%)	     mykeys %{$hashref}
     sub myopen (*;$)	     myopen HANDLE, $name
     sub mypipe (**)	     mypipe READHANDLE, WRITEHANDLE
@@ -1098,9 +1083,13 @@ follows:
 	...
     }
 
-A semicolon separates mandatory arguments from optional arguments.
+A semicolon (C<;>) separates mandatory arguments from optional arguments.
 It is redundant before C<@> or C<%>, which gobble up everything else.
 
+As the last character of a prototype, or just before a semicolon, you can
+use C<_> in place of C<$>: if this argument is not provided, C<$_> will be
+used instead.
+
 Note how the last three examples in the table above are treated
 specially by the parser.  C<mygrep()> is parsed as a true list
 operator, C<myrand()> is parsed as a true unary operator with unary
@@ -1312,10 +1301,9 @@ that understands regular expressions.
     sub glob {
 	my $pat = shift;
 	my @got;
-	local *D;
-	if (opendir D, '.') { 
-	    @got = grep /$pat/, readdir D; 
-	    closedir D;   
+	if (opendir my $d, '.') { 
+	    @got = grep /$pat/, readdir $d; 
+	    closedir $d;   
 	}
 	return @got;
     }
@@ -1367,7 +1355,8 @@ And, as you'll have noticed from the previous example, if you override
 C<glob>, the C<< <*> >> glob operator is overridden as well.
 
 In a similar fashion, overriding the C<readline> function also overrides
-the equivalent I/O operator C<< <FILEHANDLE> >>.
+the equivalent I/O operator C<< <FILEHANDLE> >>. Also, overriding
+C<readpipe> also overrides the operators C<``> and C<qx//>.
 
 Finally, some built-ins (e.g. C<exists> or C<grep>) can't be overridden.