> Dan Muey wrote:
> > Howdy list!
> >
> > Within a module function that can be exported I use a function, say
> > header() from CGI.
> > IN that module I have to have
> > use CGI qw(header);
> > OK super.
> > What about if I have a function I export that uses a function from
> > say, the DBI module, and the first argument sent to it is the Data
> > Base Handle Variable like so:
> >
> > Script:
> > use DBI;
> > use MyFunkyModule qw(databasestuff);
> > my $dbh DBI->connect.....
> >
> > print databasestuff($dbh,$query);
> >
> > MyFunkyModule.pm:
> >
> > sub databasestuff {
> > my $dbh = shift;
> > my $query = shift;
> > return $dbh->do($query);
> > }
> > (I realize that in this case I might As well just do do() but it's
> > just an example to illustrate the idea)
> >
> > Would I still have to have use DBI; in the package
> MyFunkyModule; in
> > MyFunkyModule.pm?
>
> No, not in the example you've shown.
Woo Hoo!
>
> >
> > Basically I'd like to export functions that use uncommon
> modules. I'd
> > like those functions to fail with an error if they don't have them
> > installed or give they are given a bad object, IE like if
> $dbh was a
> > simple string in my example above..
> >
> > I supposed I could do and eval on the module inside the function:
> >
> > sub databasestuff {
> > eval { use DBI; };
>
> You have to use "require" instead of "use" in a case like
> this, because "use" is a compile-time thing.
>
> > die "You need DBI installed to use this function $@"
> if($@); my $dbh =
> > shift; my $query = shift;
> > return $dbh->do($query);
> > }
> > (Yes I know DBI is a standard module, I'm just using it as
> an example
> > since most people know how to use it)
> >
> > But if the just sending $dbh part of the object would work so I
> > wouldn't have to use() it in MyFunkyModule.pm that'd be great.
>
> If you want to know if $dbh is actually a database handle,
> you can use:
>
> die "Not a DBI database handle" unless
> UNIVERSAL::isa($dbh, 'DBI::db');
>
> You can also check to see if $dbh supports a "do" method
> before calling it:
>
> die "Object doesn't have a 'do' method" unless
> UNIVERSAL::can($dbh, 'do');
>
> This won't work if do is an autoloaded method (which it isn't
> in DBI). In that case, wrapping the method call in eval() is
> the way to go.
>
Excellent info Bob thanks a bunch! I'll take somne time and digest all of that today.
Thanks!
Dan
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