The compiler is based on the following steps:
Parse => Macroexpand => CPS => Simplify => Closure Conversion => Closure Analysis => Stack => Emit C
- CPS commits us to implementing lambda efficiently
- Use XP methods, write lots of tests and automate running them
- Separation of Concerns: Divide things cleanly into modules
- Macros: develop a syntactic-closure based macro system, it will be possible to implement syntax-rules with it
- C-exprs: Make it really easy for the compiler to emit well formed C code [good progress]
- Runtime: scheme interpreter for the stack runtime, be able to execute compiled code this way to compare against emitted C
- Have several tiers of tests (simple scheme scripts to run and analyze the compilation of) [done]
- Eta reduction/other simple reductions after CPS?
- Lexical environment: to correctly handle things like (lambda (let) ... (let ...) ...) we need to carry a lexical environment around while processing terms. Practice for this would be implementing a hygienic macro system
- Stack frames: We can implement var-args and detect wrong number of args passed using stack-frames, this also opens the door to stack allocation of environments
- Closure Analysis: We must stack allocate closure/environments when possible
- Port back to chicken: Racket is frustrating - move back to chicken but need to get all the unit testing and ideally modules happening too.
| Stage | Status | Notes |
|---|---|---|
| Parser | Complete! | has nice tests |
| Macroexpand | Mostly compete | (MAC) |
| CPS | partially done | add values/multiple-values, what else? |
| Simplification | (SIMPL) | |
| Closure Conversion | ||
| Closure Analysis | (CLOSE) Learn how to do this | |
| Stack | (STACK) | |
| Emit C | Done! c-exprs | Sweet! |
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(MAC) This is all in syntactic-closures-macro-system. Need to implement and test more forms in prelude/macros.rkt
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(SIMPL) perform some simplifications such as the following [ensure that they don't break anything]
((lambda () body)) => body ((lambda (x) (... x ...)) exp) => (... exp ...) (if x is references only once) remove unused arguments to procedures (args have no side effects)
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(CLOSE) The RABBIT and ORBIT papers cover this. Need to understand this better and implement it!
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(STACK) Designing the stack runtime, implementing it in c-exprs.
To get the code use git clone --recursive since it uses submodules
Problem with empty submodules? git submodule update --init http://stackoverflow.com/questions/11358082/empty-git-submodule-folder-when-clone