ImplementSuffix is a pass for the SXML IntermediateLanguage, invoked from SXMLSimplify.

Description

This pass implements the TopLevel_setSuffix primitive, which installs a function to exit the program.

Implementation

implement-suffix.sig implement-suffix.fun

Details and Notes

ImplementSuffix works by introducing a new ref cell to contain the function of type unit -> unit that should be called on program exit.

• The following code (appropriately alpha-converted) is appended to the beginning of the SXML program:

      val z_0 = 
        fn a_0 => 
        let
           val x_0 = 
              "toplevel suffix not installed"
           val x_1 = 
              MLton_bug (x_0)
        in
           x_1
        end
     val topLevelSuffixCell = 
        Ref_ref (z_0)
  

• Any occurrence of

     val x_0 = 
        TopLevel_setSuffix (f_0)
  

  is rewritten to

     val x_0 = 
        Ref_assign (topLevelSuffixCell, f_0)
  

• The following code (appropriately alpha-converted) is appended to the end of the SXML program:

     val f_0 = 
        Ref_deref (topLevelSuffixCell)
     val z_0 = 
        ()
     val x_0 = 
        f_0 z_0