bit of line wrapping
This commit is contained in:
Torsten Ruger
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README.md
13
README.md
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@ -57,8 +57,8 @@ Parse simple code, using Parslet. This has been seperated out as it's own gem, s
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Parsing is a surprisingly fiddly process, very space and order sensitive. But Parslet is great and simple
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expressions (including function definitions and calls) are starting to work.
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I spent some time on the parse testing framework, so it is safe to fiddle and add. In fact it is very modular and
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so ot is easy to add.
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I spent some time on the parse testing framework, so it is safe to fiddle and add.
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In fact it is very modular and so ot is easy to add.
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### Virtual: Compile the Ast
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@ -94,8 +94,8 @@ So the current staus is that i can
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#### Blocks
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Implement ruby Blocks, and make new vm classes to deal with that. This is in fact a little open, but i have a general
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notion that blocks are "just" methods with even more implicit arguments.
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Implement ruby Blocks, and make new vm classes to deal with that. This is in fact a little open,
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but i have a general notion that blocks are "just" methods with even more implicit arguments.
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#### Exceptions
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@ -103,8 +103,9 @@ Implement Exceptions. Conceptionally this is not so difficult in an oo machine a
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I have a post about it http://salama.github.io/2014/06/27/an-exceptional-though.html
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which boild down to the fact that we can treat the address to return to in an exception quite like a return address
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from a function. Ie just another implicit parameter (as return is really an implicit parameter, a little like self for oo)
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which boild down to the fact that we can treat the address to return to in an exception quite
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like a return address from a function. Ie just another implicit parameter
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(as return is really an implicit parameter, a little like self for oo)
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### C linking
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@ -6,10 +6,11 @@ The Ast (abstract syntax tree) is created by salama-reader gem and the classes d
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The code in this directory compiles the AST to the virtual machine code.
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If this were an intrepreter, we would just walk the tree and do what it says. Since it's not things are a little more
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difficult, especially in time.
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If this were an intrepreter, we would just walk the tree and do what it says.
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Since it's not things are a little more difficult, especially in time.
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When compiling we deal with two times, compile-time and run-time. All the headache comes from mixing those two up.*
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When compiling we deal with two times, compile-time and run-time.
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All the headache comes from mixing those two up.*
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Similarly, the result of compiling is two-fold: a static and a dynamic part.
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@ -23,27 +24,29 @@ Each ast class gets a compile method that does the compilation.
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#### Compiled Method and Instructions
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The first argument to the compile method is the CompiledMethod. All code is encoded as a stream of Instructions in the
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CompiledMethod. Instructions are stored as a list of Blocks, and Blocks are the smallest unit of code, which is
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always linear.
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The first argument to the compile method is the CompiledMethod.
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All code is encoded as a stream of Instructions in the CompiledMethod.
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Instructions are stored as a list of Blocks, and Blocks are the smallest unit of code,
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which is always linear.
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Code is added to the method (using add_code), rather than working with the actual instructions. This is so each
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compiling method can just do it's bit and be unaware of the larger structure that is being created.
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Code is added to the method (using add_code), rather than working with the actual instructions.
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This is so each compiling method can just do it's bit and be unaware of the larger structure that is being created.
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The genearal structure of the instructions is a graph (what with if's and whiles and breaks and what),
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but we build it to have one start and *one* end (return).
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#### Messages and frames
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The virtual machine instructions obviously operate on the virtual machine. Since the machine is virtual,
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we have to define it, and since it is oo we define it in objects.
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The virtual machine instructions obviously operate on the virtual machine.
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Since the machine is virtual, we have to define it, and since it is oo we define it in objects.
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Also it is important to define how instructions operate, which is is in a physical machine would be by changing
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the contents of registers or some stack.
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Also it is important to define how instructions operate, which is is in a physical machine would
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be by changing the contents of registers or some stack.
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Our machine is ot a register machine, but an object machine: it operates directly on objects and also has no seperat
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stack, only objects. There are a number of objects which are accessible, and one can think of these (their addresses)
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as register contents. And one wouldn't be far off as that is the implementation
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Our machine is ot a register machine, but an object machine: it operates directly on objects and
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also has no seperate stack, only objects. There are a number of objects which are accessible,
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and one can think of these (their addresses) as register contents.
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And one wouldn't be far off as that is the implementation
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The objects the machine works on are:
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@ -52,12 +55,14 @@ The objects the machine works on are:
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- Self
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- NewMessage
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and working on means, these are the only objects which the machine accesses. Ie all others would have to be moved first.
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and working on means, these are the only objects which the machine accesses.
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Ie all others would have to be moved first.
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When a Method needs to make a call, or send a Message, it creates a NewMessage object.
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Messages contain return addresses and arguments.
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Then the machine must find the method to call. This is a function of the virtual machine and is implemented in ruby.
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Then the machine must find the method to call.
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This is a function of the virtual machine and is implemented in ruby.
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Then a new Method receives the Message, creates a Frame for local and temporary variables and continues execution.
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@ -66,13 +71,15 @@ The important thing here is that Messages and Frames are normal objects.
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And interestingly we can partly use ruby to find the method, so in a way it is not just a top down transformation.
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Instead the sending goes back up and then down again.
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The Message object is the second parameter to the compile method, the run-time part as it were. Why? Since it only
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exists at runtime: to make compile time analysis possible (it is after all the Virtual version, not Parfait. ie
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compile-time, not run-time). Especially for those times when we can resolve the method
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at compile time.
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The Message object is the second parameter to the compile method, the run-time part as it were.
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Why? Since it only exists at runtime: to make compile time analysis possible
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(it is after all the Virtual version, not Parfait. ie compile-time, not run-time).
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Especially for those times when we can resolve the method at compile time.
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*
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As ruby is a dynamic language, it also compiles at run-time. This line of thought does not help though as it sort of mixes
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the seperate times up, even they are not. Even in a running ruby programm the stages of compile and run are seperate.
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Similarly it does not help to argue that the code is static too, not dynamic, as that leaves us with a worse working model.
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As ruby is a dynamic language, it also compiles at run-time. This line of thought does not help
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though as it sort of mixes the seperate times up, even they are not.
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Even in a running ruby programm the stages of compile and run are seperate.
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Similarly it does not help to argue that the code is static too, not dynamic,
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as that leaves us with a worse working model.
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@ -1,7 +1,7 @@
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### Builtin module
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The Builtin module contains functions that can not be coded in ruby. It is the other side of the parfait coin, part of
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the runtime.
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The Builtin module contains functions that can not be coded in ruby.
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It is the other side of the parfait coin, part of the runtime.
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The functions are organized by their respective class and get loaded in boot_classes! , right at the start.
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@ -18,27 +18,27 @@ And thus parfait can be used at run-time.
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It's too simple: just slips off the mind like a fish into water.
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Parfait has a brother, the Builtin module. Builtin contains everything that can not be coded in ruby, but we stil need
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(things like array access).
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Parfait has a brother, the Builtin module. Builtin contains everything that can not be coded in ruby,
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but we stil need (things like array access).
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#### Example: Message send
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It felt a little stupid that it took me so long to notice that sending a message is very closely related to the
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existing ruby method Object.send
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Off course Object.send takes symbol and the arguments and has the receiver, so all the elements of our Messaage are there.
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And the process that Object.send needs to do is exactly that: send that message, ie find the correct method according to
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the old walk up the inheritance tree rules and dispatch it.
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Off course Object.send takes symbol and the arguments and has the receiver, so all the elements of our
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Messaage are there. And the process that Object.send needs to do is exactly that:
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send that message, ie find the correct method according to the old walk up the inheritance tree rules and dispatch it.
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And as all this happens at runtime, "all" we have to do is code this logic. And since it is at runtime,
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we can do it in ruby (as i said, this get's compiled and run, just like the program).
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But what about the infinite loop problem:
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There was a little step left out: Off course the method gets compiled at compile-time and so we don't just blindly dispatch:
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we catch the simple cases that we know about: layout, type instance variables and compile time known functions. Part of
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those are some that we just don't allow to be overridden.
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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
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data we need (not the object). The object receives, it does not send.
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There was a little step left out: Off course the method gets compiled at compile-time and so
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we don't just blindly dispatch: we catch the simple cases that we know about:
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layout, type instance variables and compile time known functions.
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Part of those are some that we just don't allow to be overridden.
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Also what in ruby is object.send is Message.send in salama, as it is the message we are sending and
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which defines all the data we need (not the object). The object receives, it does not send.
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@ -23,27 +23,28 @@ There are four virtual objects that are accessible (we can access their variable
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- Frame (local and tmp variables)
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- NewMessage ( to build the next message sent)
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These are pretty much the first four registers. When the code goes from virtual to register, we use register instructions
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to replace virtual ones.
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These are pretty much the first four registers. When the code goes from virtual to register,
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we use register instructions to replace virtual ones.
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Eg: A Virtual::Set can move data around inside those objects. And since in Arm this can not be done in one instruciton,
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we use two, one to move to an unused register and then into the destination. And then we need some fiddling of bits
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to shift the type info.
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Eg: A Virtual::Set can move data around inside those objects.
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And since in Arm this can not be done in one instruction, we use two, one to move to an unused register
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and then into the destination. And then we need some fiddling of bits to shift the type info.
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Another simple example is a Call. A simple case of a Class function call resolves the class object, and with the
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method name the function to be found at compile-time. And so this results in a Register::Call, which is an Arm
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instruction.
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Another simple example is a Call. A simple case of a Class function call resolves the class object,
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and with the method name the function to be found at compile-time.
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And so this results in a Register::Call, which is an Arm instruction.
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A C call
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---------
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Ok, there are no c calls. But syscalls are very similar. This is not at all as simple as the nice Class call described
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above.
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Ok, there are no c calls. But syscalls are very similar.
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This is not at all as simple as the nice Class call described above.
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For syscall in Arm (linux) you have to load registers 0-x (depending on call), load R7 with the syscall number and then
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issue the software interupt instruction. If you get back something back, it's in R0.
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For syscall in Arm (linux) you have to load registers 0-x (depending on call), load R7 with the
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syscall number and then issue the software interupt instruction.
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If you get back something back, it's in R0.
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In short, lots of shuffling. And to make it fit with our four object architecture, we need the Message to hold the data
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for the call and Sys (module) to be self. And then the actual functions do the shuffle, saving the data and restoring it.
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In short, lots of shuffling. And to make it fit with our four object architecture,
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we need the Message to hold the data for the call and Sys (module) to be self.
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And then the actual functions do the shuffle, saving the data and restoring it.
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And setting type information according to kernel documentation (as there is no runtime info)
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@ -2,9 +2,11 @@
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Knowing what's going on while coding salama is not so easy: Hence the need to look at code dumps
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Hence the need for a code/object file format (remember an oo program is just objects, some data, some code, all objects)
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Hence the need for a code/object file format
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(remember an oo program is just objects, some data, some code, all objects)
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I started with yaml, which is nice in that it has a solid implementation, reads and writes, handles arbitrary objects, handles graphs and is a sort of readable text format.
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I started with yaml, which is nice in that it has a solid implementation, reads and writes,
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handles arbitrary objects, handles graphs and is a sort of readable text format.
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But the "sort of" started to get to me, because
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@ -26,7 +28,8 @@ The main starting goal was quite like yaml, but with
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Ok, so we all heard about object files, it's the things compilers create so we don't have to have
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huge compiles and can link them later.
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Much fewer know what they include, and that is not because they are not very useful, but rather very complicated.
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Much fewer know what they include, and that is not because they are not very useful,
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but rather very complicated.
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An object machine must off course have it's own object files, because:
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@ -44,11 +47,13 @@ And so this is a little start, just some outputter.
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#### Direction
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The way this is meant to go (planned for 2020+) was a salama core with only a sof parser (as that is soo much simpler).
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The way this is meant to go (planned for 2020+) was a salama core with only a sof parser
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(as that is soo much simpler).
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Then to_ruby for all the ast classes to be able to roundtrip ruby code.
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Then go to storing sof in git, rather than ruby.
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Then write a python/java parser and respective runtime conversion. Extracting common features. With the respective
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to_python on the ast's to roundtrip that too. Have to since by now we work on sof's. Etc . ..
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Then write a python/java parser and respective runtime conversion. Extracting common features.
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With the respective to_python on the ast's to roundtrip that too.
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Have to since by now we work on sof's. Etc . ..
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@ -8,30 +8,31 @@ Symbols have similar properties and those are:
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- equality means identity
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- no change 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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It's like with Atoms: they used to be the smallest possible physical unit. Now we have electrons,
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proton and neutrons. And so objects are made up of Values (not objects), integers, floats ,
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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 of a value at runtime, also in an
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similar way that objects have their classes at runtime.
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Values have type in the same way objects have a class. We keep track of the type of a value at runtime,
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also in an similar way that objects have their classes 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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*Ast* instances get created by the salama-reader gem from source.
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Here we add compile functions to ast classes and 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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**Virtual** Instructions get further transformed into **register** instructions.
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This is done by an abstractly defined Register Machine with basic Intructions.
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A concrete implementation (like Arm) derives and creates derived Instructions.
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The transformation is implemented as **passes** to make it easier to understand what is going on. Also this makes it
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easier to add functionality and optimisations from external (to the gem) sources.
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The transformation is implemented as **passes** to make it easier to understand what is going on.
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Also this makes it easier to add functionality and optimisations from external (to the gem) sources.
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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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The final transformation assigns Positions to all boot objects (Linker) and assembles them into a
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binary representation. The data- part is then a representation of classes in the **parfait** runtime.
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And the instrucions make up the funtions.
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### Accessible Objects
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@ -42,7 +43,8 @@ Object oriented systems have data hiding. So we have access to the inner state o
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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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A single instructions (Set) allows movement of data between these.
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There are compare, branch and call intructions too.
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### Micro
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@ -53,7 +55,8 @@ As such we are aiming for integer and reference (type) support, and a minimal cl
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(object/class/aray/hash/string). It is possible to add types to the system in a similar way as we add classes,
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and also implement very machine dependent functionality which nevertheless is fully wrapped as OO.
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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 by construction CompiledMethods in code and neccesarily machine dependant.
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**Parfait** is that part of the runtime that can be coded in ruby.
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It is parsed, like any other code and always included in the resulting binary.
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**Builtin** is the part of the runtime that can not be coded in ruby (but is still needed).
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This is coded by construction CompiledMethods in code and neccesarily machine dependant.
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