C:\>ftype /?

    ASSOC .pl=PerlScript
    FTYPE PerlScript=perl.exe %1 %*

would allow you to invoke a Perl script as follows:

    script.pl 1 2 3

If you want to eliminate the need to type the extensions, then do the following:

    set PATHEXT=.pl;%PATHEXT%

and the script could be invoked as follows:

    script 1 2 3