On Mon, 2006-03-04 at 15:41 -0500, The Ghost wrote:
> based upon the string in a variable, I want to run a particular
> subroutine:
>
> my $var='cat';
> ....
> ....
> ....
> $var='fish';
>
> &$var; # I want to run fish if $var is a fish or cat if $var is a cat...
>
> sub cat { .... };
> sub dog { .... };
> ....
> sub fish { .... };
>
> For some reason I think I'll be told this is a bad idea. So what are
> my options?
>
> Ryan
>
Yes, it is a bad idea. If $var comes from user input, it is tainted (see
`perldoc perlsec` for details). That means the user can run *ANY*
subroutine. If, for example, you had a subroutine that create SQL Select
statements, the user could abduct it to read any table in your database.
Not good.
You could do as Tom Phoenix suggested and create a dispatch hash. Or you
could do this:
if( $var eq 'cat' ){
cat( @some_args );
}elsif( $var eq 'dog' ){
dog( @other_args );
pooper_scooper();
}else{
die "unknown life-form $var\n";
}
This would allow you to send arguments to the subroutines. It also
allows you to call more than one subroutine for a single $var.
--
__END__
Just my 0.00000002 million dollars worth,
--- Shawn
"For the things we have to learn before we can do them, we learn by doing them."
Aristotle
* Perl tutorials at http://perlmonks.org/?node=Tutorials
* A searchable perldoc is at http://perldoc.perl.org/
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