I'm going to develop a module that includes Variables in Strings. They must come from different files, because permissions are important. I wanted to use the ref in @INC mechanism, because I want the power of perl. But I must restrict it to the user. So the module makes checks on the source. But it fails with a mysterious ^P in the source. Only if I use -Dt on the Interpreter it doesn't fail. Here is a patch archive: 
diff -uP null/com xxx/com
--- null/com    Thu Jan  1 01:00:00 1970
+++ xxx/com    Sun Mar  2 18:51:51 2003
@@ -0,0 +1,12 @@
+  507  debugperl -DptT -we 'require "t.pl"' -Mwr=t.pl 2>&1|cat >ptT
+  508  debugperl -DpT -we 'require "t.pl"' -Mwr=t.pl 2>&1|cat >pT
+  509  grep -v '^\(' ptT|less
+  510  grep -v '^(' ptT|less
+  511  less pT
+  512  grep -v '^(' ptT|diff - pT|less
+  513  grep -v '^(' ptT|diff pT - |less
+  514  man diff
+  515  grep -v '^(' ptT|diff -yu pT - |less
+  516  grep -v '^(' ptT|diff -y pT - |less
+  517  grep -v '^(' ptT|diff -y pT - |less>err
+  518  history>com
diff -uP null/t.pl xxx/t.pl
--- null/t.pl    Thu Jan  1 01:00:00 1970
+++ xxx/t.pl    Fri Feb 28 10:10:03 2003
@@ -0,0 +1,11 @@
+'dudu'
+<HTML>
+<HEAD>
+ <TITLE>Testseite</TITLE>
+</HEAD>
+<BODY>
+    TesT!!Test!TEST!!${u}
+</BODY>
+$@;
+</HTML>
+</HTML>
diff -uP null/wr.pm xxx/wr.pm
--- null/wr.pm    Thu Jan  1 01:00:00 1970
+++ xxx/wr.pm    Fri Feb 28 13:36:06 2003
@@ -0,0 +1,66 @@
+package wr;
+sub import{
+    shift;
+    my $sub=shift;
+    if(ref$sub){
+    $@='@';
+    print $sub->()."</HTML>\n";
+    }else{
+    unshift @::INC,($sub=[sub{
+        #print @_;
+        my $me=shift;#print @$me;
+        my $file=shift;
+        return if $file ne $me->[1];
+        my $ret="";
+        for my $p (@::INC){
+        $ret=1,next if$p eq$me;
+        next unless $ret;
+        my$et;
+        open  $et,"<","$p/$file" and $ret=$et,last;#print "$p/$file$!
+\n";
+        }#print"---$!",$ret;
+        return unless ref$ret;#print "+++$file";
+        return(sub{
+        my $m=$_[1];
+        return 0 unless defined $m->[1];
+        my$c=3;
+        while(length($_=$m->[1])||$c--){
+            my $n=$_[0];
+            my $r=$m->[3]->($m->[4]);
+            if($n){
+            if($n<=length){
+                $n=substr$_,0,$n;
+                $_=substr$_,length$n;
+                ($_,$n)=($n,$_);
+                $m->[1]=$n;print"§";
+                return length;
+            }
+            }else{
+            if($n=1+index($_,"\n")){
+                $n=substr$_,0,$n;
+                $_=substr$_,length$n;
+                ($_,$n)=($n,$_);
+                $m->[1]=$n;print;
+                return length;
+            }
+            }
+            undef$m->[0]unless ref$r;
+            $m->[2]=~s/($r)//;
+            $m->[1].=$1;
+            next if length $1;
+            return 0 unless$n=$m->[0];
+            $m->[2].=<$n>;
+        }
+        return 0;
+        },[$ret,'use '.__PACKAGE__.
+           ' sub{package al;<<"</HTML>"},','',$me->[2]])
+    },$sub,sub{local$;='$;';s{^(</HTML>)$}{$1\n;return$;;\n}#and retu
+rn'${'
+               ;return qr/([^\\\$@]|[a]|\$([@"]|\{[a-zA-Z0-9]+\}))*/m
+s;}]);
+    return $sub;
+    }
+}
+1;
+
+
+
+
+

[download]
By the way: I use the perl of the debian woody distribution.

In reply to ref in @INC and debugging by Anonymous Monk

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