From: Sven Verdoolaege <skimo@breughel.ufsia.ac.be>
Date: Thu, 29 Aug 1996 13:14:51 +0000 (+0200)
Subject: more TIEHANDLE
X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=commitdiff_plain;h=58f51617c7df66bccaec3ed5e7aa1f1bd5ca8566;p=p5sagit%2Fp5-mst-13.2.git

more TIEHANDLE

This adds support for a READLINE method.
---

diff --git a/pod/perltie.pod b/pod/perltie.pod
index c5d3686..41517ac 100644
--- a/pod/perltie.pod
+++ b/pod/perltie.pod
@@ -611,10 +611,8 @@ use the each() function to iterate over such.  Example:
 
 This is partially implemeted now.
 
-A class implementing a tied scalar should define the folowing methods:
-TIEHANDLE, PRINT, and possibly DESTROY.
-
-In future READLINE, EOF and possibly others will be added.
+A class implementing a tied filehandle should define the folowing methods:
+TIEHANDLE, PRINT and/or READLINE, and possibly DESTROY.
 
 It is especially useful when perl is embedded in some other program,
 where output to STDOUT and STDERR may have to be redirected in some
@@ -632,7 +630,7 @@ This is the constructor for the class.  That means it is expected to
 return a blessed reference of some sort. The refence can be used to
 hold some internal information. We won't use it in out example.
 
-    sub TIEHANDLE { print "<shout>\n"; bless [], shift }
+    sub TIEHANDLE { print "<shout>\n"; my $i; bless \$i, shift }
 
 =item PRINT this, LIST
 
@@ -640,7 +638,14 @@ This method will be triggered every time the tied handle is printed to.
 Beyond its self refence it also expects the list that was passed to
 the print function.
 
-    sub PRINT { shift; for (@_) { print uc($_) } }
+    sub PRINT { $r = shift; $$r++; print join($,,map(uc($_),@_)),$\ }
+
+=item READLINE this
+
+This method will be called when the handle is read from. The method
+should return undef when there is no more data.
+
+    sub READLINE { $r = shift; "PRINT called $$r times\n"; }
 
 =item DESTROY this
 
@@ -658,6 +663,7 @@ Here's how to use our little example:
     print FOO "hello\n";
     $a = 4; $b = 6;
     print FOO $a, " plus ", $b, " equals ", $a + $b, "\n";
+    print <FOO>;
 
 =head1 SEE ALSO
 
diff --git a/t/op/misc.t b/t/op/misc.t
index 3b88a0a..e3bf576 100755
--- a/t/op/misc.t
+++ b/t/op/misc.t
@@ -179,6 +179,9 @@ BEGIN failed--compilation aborted at - line 1.
     sub TIEHANDLE {
         bless {}, shift;
     }
+    sub READLINE {
+	"Out of inspiration";
+    }
     sub DESTROY {
 	print "and destroyed as well\n";
     }
@@ -187,7 +190,9 @@ BEGIN failed--compilation aborted at - line 1.
     local(*FOO);
     tie(*FOO,'foo');
     print FOO "sentence.", "reversed", "a", "is", "This";
+    print "-- ", <FOO>, " --\n";
 }
 EXPECT
 This is a reversed sentence.
+-- Out of inspiration --
 and destroyed as well