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Re: feedback on subroutine as both function and method in one

by andreychek (Parson)
on Jul 12, 2001 at 21:28 UTC ( #96120=note: print w/replies, xml ) Need Help??

in reply to feedback on subroutine as both function and method in one

Just for fun, this is how CGI goes about doing it:
sub param { my($self,@p) = self_or_default(@_); blah blah... } sub self_or_default { return @_ if defined($_[0]) && (!ref($_[0])) &&($_[0] eq 'CGI'); unless (defined($_[0]) && (ref($_[0]) eq 'CGI' || UNIVERSAL::isa($_[0],'CGI')) # sli +ghtly optimized for common case ) { $Q = $CGI::DefaultClass->new unless defined($Q); unshift(@_,$Q); } return wantarray ? @_ : $Q; }
The very first thing done when a sub is called is to test the parameters passed to it.. to see if it's being called as a function or method. Now, if I'm reading this correctly, it would seem that if it's not being called as an object method, then it is turned into an object. Otherwise, it leaves it alone and returns the parameters as is (leaving it as an object).

So, perhaps I can go as far as saying that everything inside CGI is treated as an object, no matter how you call it.

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Re: Re: feedback on subroutine as both function and method in one
by bikeNomad (Priest) on Jul 12, 2001 at 22:58 UTC
    It's interesting that it always does the unshift, even if it's not called in array context. I could see that being a problem when subclassing CGI:

    my $cgi = $self_or_default(@_); $cgi->param(@_); # oops, now I have an extra CGI as first arg.

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[ambrus]: Today I accidentally cut my hand while carrying a computer. On the display part of the motherboard that sticks out at the back of the chasis and has ports, there's this thin metal sheet with holes cut for the ports, to guide plugs into the sockets.
[ambrus]: This sheet has sharp needle-like parts, 0.004 long and less than 0.001 wide, that can get bent to point outwards, and one of these cut into my palm when I lifted the box.
[ambrus]: So now when I choose what motherboard to buy for my new home computer, I have one more specific property to guide me. Useful, because there's so many different boards to choose from.
[Corion]: Well, no computer will start up without the blood sacrifice being made!

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