# -*- cperl -*-

=head1 Perl Array PMC

=head2 Creation

To create a new PMC with a PerlArray object:

   new P0, .PerlArray

=head2 Size

Perl array can be initialized to the empty array using

   set P0, 0

and we can check the PerlArray size, putting the value on register
C<I0> using

   set I0, P0

We can create an empty array but with some chunks allocated. This method is the
same to initialize the array to the empty array. In this case, use the number of
chunks you want:

   set P0,5

=head2 Index access

You can set the value 3 on the position 5 from the array using

   set P0[5] 3

In the same mood, to access the element use

   set I0, P0[5]

As in Perl, negative indexes are seen as indexes from the end of the
array. This way, you can set the last element of the array to the
value 7 using

   set P0[-1], 7

Note that you can put on each chunk a integer, number, string or
PMC. You must have caution when accessing the value, as you should use
the correct type of register.

=head2 Using keys of different types

You can use string or numbers as indexes for the array if they
represent an integer.  So, these are correct instructions:

   set P0[5.0], 3
   set P0["10"], 6
   set P0[15], 9

which sets values on positions 5, 10 and 15.

=head2 Trueness

You can get a boolean value from a Perl Array.  If you use an empty
Perl Array in a condition, it will return false (no elements).

        new P0, .PerlArray
        if P0, JUMP         # This will never succeed

After adding a value (for example, P0[0] = 1), it will return a true
value (the Perl Array has elements).

        new P0, .PerlArray
        set P0, 0, 1
        if P0, JUMP         # This will succeed

If you don't add a value, but force a size different from zero the the
array, it will return a true value:

        new P0, .PerlArray
        set P0, 1
        if P0, JUMP         # This will succeed

=cut