Re: [MacPerl] Complex data structure building

[pudge@pobox.com (Chris Nandor)]

At 08.50 98.01.19, Wade Williams wrote:
>I realize this is a bit of a general question, but I thought some here
>might have some solutions.
>
>One of the things I used to love about the Think C debugger was that it
>allowed me to figure out complex dereferences.  Need to know how a pointer
>to a record containing a pointer to an array would look?  Just play around
>with it in the debugger until you hit on the combination that displays the
>proper data.  Hmm...*myrec->array[0] doesn't work...maybe it's
>(*(myrec->array))[0]....things like that.
>
>I'm having difficulty understanding how to build and reference complex data
>structures in Perl.  Now, generally, I'm a pretty bright guy, but the idea
>of references just hasn't clicked yet.  I've read all the man pages, the
>Camelbook, etc, but I'm still struggling.  Let's see..should that be
>$myarray[0][0], $myarray->[0][0] or @$myarray[0][0]?
>
>In short, other than trying "print somecombination" until I get the right
>data printed, does anyone have any tips for either tools to help you
>reference complex structures correctly, or any pointers to any more
>tutorial information which can help me get over the hump on the whole
>references/complex structures issue.

IMO, the best ways to learn about these structures are:

* the man pages perlref, perldsc, perllol
* the Data::Dumper module

An example of Data::Dumper:

use Data::Dumper;
$a[0][0]     = 'b';
$i->[0][0]   = 'j';
$m[0]->[0]   = 'n';
$x->[0]->[0] = 'y';

print Dumper \@a, $i, \@m, $x;

But personally, I like to construct my data structures like this so I can
see what is going on:

@a = (['b']);
$i = [['j']];
@m = (['n']);
$x = [['y']];

If you use these statements instead of the others, you might notice that
the print statement still prints the same thing.  Just remember that
[0..10] is an anonymous reference to an array, {a=>1} is an anonymous
reference to a hash.

$pets = {Dogs=>['Banjo','Opie','Tubb'], Cats=>['Fester']};

Have fun,

--
Chris Nandor               pudge@pobox.com           http://pudge.net/
%PGPKey=('B76E72AD',[1024,'0824 090B CE73 CA10  1FF7 7F13 8180 B6B6'])
#==                    MacPerl: Power and Ease                     ==#
#==    Publishing Date: Early 1998. http://www.ptf.com/macperl/    ==#



***** Want to unsubscribe from this list?
***** Send mail with body "unsubscribe" to mac-perl-request@iis.ee.ethz.ch