Re: separating functionality

[drieux]

On Friday, Sep 26, 2003, at 18:07 US/Pacific, [EMAIL PROTECTED] wrote:
[..]
Can someone just
point the way? Lets say i want to create a file in lib/favfuncs.pl. I
would call funcs in favfuncs.pl in my other perl progs.
[..]

Dan has clearly pointed you in the right direction,

You will want to put them in a file named

	favfuncs.pm

so that it will be simpler to

	use favfuncs ;

because 'use' is looking for files that are suffix'd as 'pm'.

Another rule to keep in minds is that 'all low case' is
reserved for 'pragma' - so it is best to make that a
mix of upper and lower case - per the documentation
	use FavFuncs.

Hence the file would be FavFuncs.pm, and the first line
would be declaring the package.
	package FavFuncs;

at that point you need to decide whether you want to be
exporting the 'names' of your functions/subs into the
code that will be using it - hence how to do 'Exporter'
cf: perldoc Exporter - but you will also want to read
up on perldoc h2xs - since it will help making the basic
'framework' for you.
If you are just providing a stack of functionality, you can
still use the 'OO-ish' approach, so you would want say
    #---------------------------------------------------------
        # our constructor - plain vanilla new
        #---------------------------------------------------------
        sub new
        {
                my $type  = shift;
        my $class = ref($type) || $type;
        my $self = {};  
        bless $self, $class;
	} # end of our simple new

        #---------------------------------
        # so that AUTOLOAD finds one here
	sub DESTROY {}

which of course will require that you 'tweek' any of your
basic functions which took arguments from the form:
        sub fon_gu_lea {
                my ($var1,$var2,$var3) = @_;
                ....
        }
into the 'more complex'

        sub fon_gu_lea {
                my $me = shift;
                my ($var1,$var2,$var3) = @_;
                ....
        }
{ for real fun, actually READ the perl module CGI.pm with
perldoc -m CGI - there is some serious rocket science... }
I use $me because it is two letters, self and this are four,
and that is way too much typing.
Now, yes, I know you asked about ONLY 'functions' - but as I noted
above, to make a module with fon_gu_lea() and simply export it into
the callers code, is actually a bit more work in some respects. Where
as this way while it may seem like a lot of upfront work and all you
really get is the simpler transition from
	my $foo_bar = fon_gu_lea(@arglist);

and this appears to be transitioning into

        my $funkMgr = new FavFuncs;
        my $foo_bar = $funkMgr->fon_gu_lea(@arglist);
when you get into the place where you have finished arguing with
yourself about where to cache which sets of functionality, and
whether or not to make classes that pass along by inheritence
the base set of methods, and then the sub_classes add in the
additional ones, and... and... and....
        my $funkMgr = new Foo::Bar::Baz::FavFuncs;
        my $foo_bar = $funkMgr->fon_gu_lea(@arglist);
will seems a reasonable exchange.

But you will probably want to check out Randall Schwartz's new
book about learning perl modules, references, et al...
ciao
drieux
---

Remember if you play fairways and greens, you really
only need the bigDog, a seven iron, and a putter. But
otherwise you will need to get the rest of the woods,
and the irons, and then get a caddy.... But always remember,
Never play golf with anyone who brought their own golf green.



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