55 lines
2.2 KiB
Markdown
55 lines
2.2 KiB
Markdown
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### Virtual OO Machine
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This is really an OV (object value) not object oriented machine.
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Integers and References are Values. We make them look like objects, sure, but they are not.
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Symbols have similar properties and those are:
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- eqality means identity
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- no chhange over lifetime
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It's like with Atoms: they used to be the smallest possible physical unit. Now we have electrons, proton and neutrons.
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And so objects are made up of Values (not objects), integers, floats , references and possibly more.
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Values have type in the same way objects have a class. We keep track of the type at runtime.
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### Layers
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*Ast* instances get created by the salama-reader gem from source. Here we add compile functions to ast classes and
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comile the ast layer into Virtual:: objects
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The main objects are BootSpace (lots of objects), BootClass (represents a class),
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CompiledMethod (with Blocks and Instruction).
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*Virtual* Instructions get further transformed into *register* instructions. This is done by an abstractly defined
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Register Machine with basic Intructions. A concrete implementation (like Arm) derives and creates derived
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Instructions.
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The final transformation assigns Positions to all boot objects (Linker) and assembles them into a binary representation.
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The data- part is then a representation of classes in the *parfait* runtime. And the instrucions make up the
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funtions.
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### Accessible Objects
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Object oriented systems have data hiding. So we have access to the inner state of only four objects:
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- Self
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- Message (arguments, method name, self)
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- Frame (local and tmp variables)
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- NewMessage ( to build the next message sent)
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A single instructions (Set) allows movement of data between these. There are compare, branch and call intructions too.
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### Micro
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The micro-kernel idea is well stated by: If you can leave it out, do.
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As such we are aiming for integer and reference (type) support, and a minimal class system
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(object/class/aray/hash/string).
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*Parfait* is that part of the runtime that can be coded in ruby. It is parsed, like any other code and always included
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in the resulting binary. Builtin is the part of the runtime that can not be coded in ruby (but is still needed). This
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is coded y construction CompiledMethods in code and neccesarily machine dependant.
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