Re: Limit number of Sub routine argument list

[JavaFan]

Can we strict the subroutine in perl to receive number of arguments ?

Runtime? Compile time? Is @a considered to be one argument, or as many arguments as @a has elements?

Runtime is easy:

sub foo {
    unless (@_ <= 4) {
        die "foo allows at most 4 arguments";
    }
    ...
}

Compile time, you can do:

sub foo (;$$$$) {
    ...
}

The disadvantage of the latter is that it evaluates all the arguments to the sub in scalar context, and hence there's no flattening of lists. That is,

@bar = qw[red blue green yellow brown pink];
foo @bar;

is not an error - it calls foo with a single argument, 6; the number of elements in @bar.

[ganeshwari]

thanks for your replies. I need to handle this in compile time only. But as Alexander told we can bypass this by calling the subroutine as &subroutine(..). Is there way to handle this ?

[ysth]

Can you explain why you "need" to do that?

[JavaFan]

But as Alexander told we can bypass this by calling the subroutine as &subroutine(..). Is there way to handle this ?

Not on the level of Perl itself. You may be able to do something by inspecting the op-tree. Perhaps perlcritic can help you as well, but that requires a separate stage.