# New Ticket Created by Alberto Simoes # Please include the string: [perl #21759] # in the subject line of all future correspondence about this issue. # <URL: http://rt.perl.org/rt2/Ticket/Display.html?id=21759 >
Hi, I'm back to business (I hope). If someone remember, I wrote some pods about using some PMCs. At the moment I started rewriting some of them. Here I send the first one, and ask to include it on the parrot source tree at 'docs/pmcs' as 'array.pod'. If you think it can be usefull, insert it in the parrot tree an e-mail me. I'll prepare another PMCs. I accept suggestions, too! Best regards, Alberto Simões -- Departamento de Informatica - Universidade do Minho "The C Programming Language -- A language which combines the flexibility of assembly language with the power of assembly language." -- attachment 1 ------------------------------------------------------ url: http://rt.perl.org/rt2/attach/54377/40995/9e7801/array.pod
# -*- cperl -*- =head1 Array base class This pod file documents the Array base class usage. For implementation details you should look inside the class file, found on C<classes/array.pmc> in the parrot source code. =head2 Creation As any other PMC, the following line creates an array PMC on register C<P0>. new P0, .Array As soon the array is created, you can test if it is defined using: defined I0, P0 which will put C<1> on C<I0> if it is defined, otherwise, C<0>. =head2 Array sizes When used on numeric context the PMC register containing the array object contains the size of the array. You can use set I0, P0 to retrieve to C<I0> the size of the array on register C<P0>. In the same way, you can assign directly the size of the array using set P0, 2 which will expand the array size to two. =head2 Accessing elements Elements are accessed using indexes, as in any programming language. Notice that these arrays do not expand as Perl arrays, when you access non-existing indexes. The following code initializes an array on C<P0> with size two, and sets the first position with an integer C<-8> and second position with a real, C<3.1415>. new P0, .Array set P0, 2 set P0[0], -8 set P0[1], 3.1415 It must be clear that you can assign directly from a register. Check this second example, with the same meaning: new P0, .Array set P0, 2 set I0, -8 set N0, 3.1415 set P0[0], I0 set P0[1], N0 To retrieve the elements we use the same syntax, switching registers: set N1, P0[1] set I1, P0[0] These two lines retrieve the values from the array back to registers. Whenever you want, it is possible to change the value type on some position: set P0[1], "A string" Accessing an out-of-bounds array element, an exception will be raised (as soon as we have exceptions). You can test if there is a defined element on some array position using defined I0, P0[1] for the position you want to test. On the other hand, if you want only to test if there is an element (rather than testing if it is defines) you should use the C<exists> keyword: exists I0, P0[0] =head2 TODO Explain a little more which exception will be raised in case you access a out-of-bounds index on the array (as soon we have exceptions). =cut
