rubyx/lib/parfait/README.md

### Parfait: a thin layer

Parfait is the run-time of the vm. 
To be more precise, it is that part of the run-time that can be expressed in ruby.

The run-time needs to contain quite a lot of functionality for a dynamic system.
And a large part of that functionality must actually be used at compile time too. 

We reuse the Parfait code at compile-time, by inlining it.

A work in progress that started from here : http://salama.github.io/2014/06/10/more-clarity.html went on here
http://salama.github.io/2014/07/05/layers-vs-passes.html

A step back:  the code (program) we compile runs at run - time. 
And so does parfait. So all we have to do is compile it with the program.

And thus parfait can be used at run-time.

It's too simple: just slips off the mind like a fish into water.

Parfait has a brother, the Builtin module. Builtin contains everything that can not be coded in ruby,
but we stil need (things like array access).

#### Example: Message send

It felt a little stupid that it took me so long to notice that sending a message is very closely related to the
existing ruby method Object.send

Off course Object.send takes symbol and the arguments and has the receiver, so all the elements of our
Messaage are there. And the process that Object.send needs to do is exactly that: 
send that message, ie find the correct method according to the old walk up the inheritance tree rules and dispatch it.

And as all this happens at runtime, "all" we have to do is code this logic. And since it is at runtime, 
we can do it in ruby (as i said, this get's compiled and run, just like the program).

But what about the infinite loop problem:

There was a little step left out: Off course the method gets compiled at compile-time and so
we don't just blindly dispatch: we catch the simple cases that we know about:
layout, type instance variables and compile time known functions.
Part of those are some that we just don't allow to be overridden.

Also what in ruby is object.send is Message.send in salama, as it is the message we are sending and
which defines all the  data we need (not the object). The object receives, it does not send.