34 lines
1.9 KiB
Ruby
34 lines
1.9 KiB
Ruby
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module Vm
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# The ObjectMachine is the object-oriented virtual machine in which ruby is implemented.
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#
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# It is minimal and realistic and low level
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# - minimal means that if one thing can be implemented by another, it is left out. This is quite the opposite from
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# ruby, which has several loops, many redundant if forms and the like.
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# - realistic means it is easy to implement on a 32 bit machine (arm) and possibly 64 bit. Memory access, a stack,
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# some registers of same size are the underlying hardware. (not ie byte machine)
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# - low level means it's basic instructions are realively easily implemented in a register machine. ie send is not
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# a an instruction but a function.
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#
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# A better name may be Value-based machine. Ie all "objects" are values, all passing is value based.
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# The illusion of objects is created by a value called object-reference.
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#
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# So the memory model of the machine allows for indexed access into and "object" . A fixed number of objects exist
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# (ie garbage collection is reclaming, not destroying and recreating) although there may be a way to increase that number.
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#
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# The ast is transformed to object-machine objects, some of which represent code, some data.
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#
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# The next step transforms to the register machine layer, which is what actually executes.
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#
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# More concretely, an object machine is a sort of oo turing machine, it has a current instruction, executes the
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# instructions, fetches the next one and so on.
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# Off course the instructions are not soo simple, but in oo terms quite so.
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#
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# The machine has a no register, but local variables, a scope at each point in time.
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# Scope changes with calls and blocks, but is saved at each level. In terms of lower level implementation this means
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# that the the model is such that what is a variable in ruby, never ends up being just on the cpu stack.
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#
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class ObjectMachine
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end
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end
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