HCoop / hcoop / debian / mlton.git / blame
| Commit | Line | Data |
|---|---|---|
| 7f918cf1 CE |
1 | LambdaFree |
| 2 | ========== | |
| 3 | ||
| 4 | <:LambdaFree:> is an analysis pass for the <:SXML:> | |
| 5 | <:IntermediateLanguage:>, invoked from <:ClosureConvert:>. | |
| 6 | ||
| 7 | == Description == | |
| 8 | ||
| 9 | This pass descends the entire <:SXML:> program and attaches a property | |
| 10 | to each `Lambda` `PrimExp.t` in the program. Then, you can use | |
| 11 | `lambdaFree` and `lambdaRec` to get free variables of that `Lambda`. | |
| 12 | ||
| 13 | == Implementation == | |
| 14 | ||
| 15 | * <!ViewGitFile(mlton,master,mlton/closure-convert/lambda-free.sig)> | |
| 16 | * <!ViewGitFile(mlton,master,mlton/closure-convert/lambda-free.fun)> | |
| 17 | ||
| 18 | == Details and Notes == | |
| 19 | ||
| 20 | For `Lambda`-s bound in a `Fun` dec, `lambdaFree` gives the union of | |
| 21 | the frees of the entire group of mutually recursive functions. Hence, | |
| 22 | `lambdaFree` for every `Lambda` in a single `Fun` dec is the same. | |
| 23 | Furthermore, for a `Lambda` bound in a `Fun` dec, `lambdaRec` gives | |
| 24 | the list of other functions bound in the same dec defining that | |
| 25 | `Lambda`. | |
| 26 | ||
| 27 | For example: | |
| 28 | ---- | |
| 29 | val rec f = fn x => ... y ... g ... f ... | |
| 30 | and g = fn z => ... f ... w ... | |
| 31 | ---- | |
| 32 | ||
| 33 | ---- | |
| 34 | lambdaFree(fn x =>) = [y, w] | |
| 35 | lambdaFree(fn z =>) = [y, w] | |
| 36 | lambdaRec(fn x =>) = [g, f] | |
| 37 | lambdaRec(fn z =>) = [f] | |
| 38 | ---- |