HCoop / hcoop / debian / mlton.git / blame
| Commit | Line | Data |
|---|---|---|
| 7f918cf1 CE |
1 | XMLSimplifyTypes |
| 2 | ================ | |
| 3 | ||
| 4 | <:XMLSimplifyTypes:> is an optimization pass for the <:XML:> | |
| 5 | <:IntermediateLanguage:>, invoked from <:XMLSimplify:>. | |
| 6 | ||
| 7 | == Description == | |
| 8 | ||
| 9 | This pass simplifies types in an <:XML:> program, eliminating all | |
| 10 | unused type arguments. | |
| 11 | ||
| 12 | == Implementation == | |
| 13 | ||
| 14 | * <!ViewGitFile(mlton,master,mlton/xml/simplify-types.sig)> | |
| 15 | * <!ViewGitFile(mlton,master,mlton/xml/simplify-types.fun)> | |
| 16 | ||
| 17 | == Details and Notes == | |
| 18 | ||
| 19 | It first computes a simple fixpoint on all the `datatype` declarations | |
| 20 | to determine which `datatype` `tycon` args are actually used. Then it | |
| 21 | does a single pass over the program to determine which polymorphic | |
| 22 | declaration type variables are used, and rewrites types to eliminate | |
| 23 | unused type arguments. | |
| 24 | ||
| 25 | This pass should eliminate any spurious duplication that the | |
| 26 | <:Monomorphise:> pass might perform due to phantom types. |