doc/guide/src/XMLSimplifyTypes.adoc

   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.