55 lines
1.8 KiB
Ruby
55 lines
1.8 KiB
Ruby
module Virtual
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# So when an object calls a method, or sends a message, this is what a sends: a Message
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# A message contains the sender, return and exceptional return addresses,the arguments, and a slot for the frame.
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# As such it is a very run-time object, deep in the machinery as it were, and does not have meaningful
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# methods you could call at compile time.
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# The methods that are there, are nevertheless meant to be called at compile time and generate code, rather than
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# executing it.
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# The caller creates the Message and passes control to the receiver's method
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# The receiver create a new Frame to hold local and temporary variables and (later) creates default values for
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# arguments that were not passed
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# How the actual finding of the method takes place (acording to the ruby rules) is not simple, but as there is a
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# guaranteed result (be it method_missing) it does not matter to the passing mechanism described
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# During compilation Message and frame objects are created to do type analysis
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class Message
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def initialize me , normal , exceptional
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@me = me
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@next_normal = normal
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@next_exception = exceptional
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# a frame represents the local and temporary variables at a point in the program.
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@frame = []
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end
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attr_reader :me, :next_normal, :next_exception, :frame
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# dummy for the eventual
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def new_frame
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self
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end
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#
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def compile_get method , name
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method.add FrameGet.new(name)
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method.get_var(name)
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end
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def compile_send method , name , me , with = []
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method.add Virtual::LoadSelf.new(me)
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method.add FrameSend.new(name , with )
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Return.new( method.return_type )
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end
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def compile_set method , name , val
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method.set_var(name,val)
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method.add FrameSet.new(name , val )
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method.get_var(name)
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end
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end
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end
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