A variation on some of solutions already suggested (also a closure, but not an anonymous one), shown under the Perl debugger:

  DB<1> $variable = 3;

  DB<2> sub string(){"Variable = $variable\n";}

  DB<3> print string;
Variable = 3

  DB<4> $variable = 4;

  DB<5> print string;
Variable = 4
[download]

It almost looks like what you're looking for, doesn't it?