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