Hi,
With much of PDD15 implemented, I thought it'd be good to explain how
far along we are (and aren't) as the next release approaches. Here's
some code examples.
---
# You can initialize a class with a hash...
$P0 = new 'Hash'
# Set name Will also associate with Monkey namespace nested in current NS.
# You can set $P0['namespace'] instead (or as well) to specify a full keyed
# namespace, which is taken to be from the HLL root.
$P0['name'] = 'Monkey'
# Make an array of attributes.
$P1 = new 'ResizableStringArray'
$P1[0] = 'banana'
$P0['attributes'] = $P1
# Let's create a class!
$P1 = new 'Class', $P0
# You can add stuff to it later too, provided it ain't instantiated yet.
$P2 = find_global 'say_ook'
add_method $P1, 'say_ook', $P2
# Add parents...
$P2 = get_class 'Primate'
add_parent $P1, $P2
# Create a role...
$P0 = new 'Hash'
$P0['name'] = 'JungleActivities'
$P2 = new 'Role', $P0
$P3 = find_global 'ja_swing'
add_method $P2, 'swing', $P3
# And compose it in! If we wanted to resolve conflicts, can use
'add_role' method.
add_role $P1, $P2
# Instantiate it.
$P2 = $P2.new()
# Call methods and get/set attributes just as before.
$P2.swing()
$P3 = new 'Banana'
setattribute $P2, 'banana', $P3
$P2.say_ook()
# Inspect a class to find out about its guts.
$P3 = inspect $P1
$P4 = inspect $P1, 'attributes'
# Here's now to instantiate a class associated with a given namespace...
$P5 = get_class [ 'Creation', 'Animals', 'Monkey' ]
$P6 = $P5.new()
---
Excuse any typo's in the above. As you can see, fairly capable. However,
there's still some work to do and limitations.
* addattribute segfaults if passed a PDD15 class. I'll fix that
tomorrow, if nobody beats me to it
* Oh, and the Role PMC doesn't do the name/namespace stuff right yet;
it's mostly a case of looking at the Class PMC and stealing stuff.
Doable before release...again, please beat me to it. ;-)
* The Object PMC is missing some vtable methods and its guts need
sorting out - also probably doable before release - I'll have time for
this pre-release too
* You can't inherit from a PMC yet. Depends on needed stuff being spec'd
and implemented.
* Overriding of vtable methods ain't implemented yet
* Attribute composition from roles ain't implemented yet
So I think we're looking at having PDD15 usable by some people in this
release, but not being able to inherit from PMCs is going to prevent a
lot of people jumping over to it just yet. It'll probably be a little
while before we can really deprecate ParrotClass and ParrotObject. What
we certainly need is more test coverage and feedback from people using
the new stuff.
I'm aware that I probably have the most in-depth knowledge of the PDD15
implementation. Parrot's losing me for pretty much all of May, so if
anyone has questions on the code, please try and catch me about them
within the next week, either on list or IRC.
Have fun,
Jonathan
