46 lines
1.5 KiB
Ruby
46 lines
1.5 KiB
Ruby
module Virtual
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# So when an object calls a method, or sends a message, this is what it sends: a Message
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# A message contains the sender, return and exceptional return addresses,the arguments,
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# 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
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# meaningful 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
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# code, rather than 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
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# default values for 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,
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# but as there is a guaranteed result (be it method_missing) it does not matter to the passing
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# 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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SELF_REG = :r0
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MESSAGE_REG = :r1
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FRAME_REG = :r2
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NEW_MESSAGE_REG = :r3
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TMP_REG = :r4
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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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@arguments = arguments
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# a frame represents the local and temporary variables at a point in the program.
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@frame = nil
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end
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attr_reader :me, :next_normal, :next_exception, :arguments , :frame
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#
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end
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end
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