or download this
c:\@Work\Perl\monks>perl -wMstrict -le
"my $text = 'text with a <%VAR%> and <%FOO%> to interpolate <%OOPS%>';
...
regex: (?msx-i: VAR|FOO )
'text with a Value Taken From A Data Structure and Another One to inte
+rpolate <%OOPS%>'
unable to interpolate '<%OOPS%>' at offset 77