diff --git a/lib/parfait/README.md b/lib/parfait/README.md index 2a2f3350..1e22aeb8 100644 --- a/lib/parfait/README.md +++ b/lib/parfait/README.md @@ -4,4 +4,42 @@ Here we have a placeholder for things i am currently developing. Basically Parfait is the smallest amount of code needed to make a ruby-like OO system work. -A work in progress that started from here : http://salama.github.io/2014/06/10/more-clarity.html +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 + +And i finally came to the conclusion that Parfait is the ruby runtime. Aha + +Run - time + +not compile - time + +always mixing those up: As such it is not loaded at compile time. + +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. + +#### Example: Message send + +I felt a little stupid that it took me so long to notice that sending a message is very closely relateed 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. + diff --git a/lib/parfait/array.rb b/lib/parfait/array.rb index e9b5065b..8f0abef6 100644 --- a/lib/parfait/array.rb +++ b/lib/parfait/array.rb @@ -1,5 +1,5 @@ # this is not a "normal" ruby file, ie it is not required by salama -# instead it is parsed by salama to define part of the salama that runs +# instead it is parsed by salama to define part of the program that runs class Array < BaseObject def initialize size diff --git a/lib/parfait/message.rb b/lib/parfait/message.rb new file mode 100644 index 00000000..e7b9a331 --- /dev/null +++ b/lib/parfait/message.rb @@ -0,0 +1,24 @@ +# this is not a "normal" ruby file, ie it is not required by salama +# instead it is parsed by salama to define part of the program that runs + +class Message + def send + # Find the method for the given object (receiver) according to ruby dispatch rules: + # - see if the receiver object has a (singleton) method by the name + # - get receivers class and look for instance methods of the name + # - go up inheritance tree + # - start over with method_missing instead + # -> guaranteed to end at object.method_missing + method = @receiver.get_singeton_method @method_name + unless method + cl = @receiver.layout.object_class + method = cl.get_instance_or_super_method @method_name + end + unless method + message = Message.new( @receiver , :method_missing , [@method_name] + @args) + message.send + else + method.call + end + end +end diff --git a/lib/parfait/object.rb b/lib/parfait/object.rb index 5ac0e951..879295ed 100644 --- a/lib/parfait/object.rb +++ b/lib/parfait/object.rb @@ -1,2 +1,6 @@ +# this is not a "normal" ruby file, ie it is not required by salama +# instead it is parsed by salama to define part of the program that runs + class Object + end