regression/llv.sml

   1
   2 structure LLV =
   3   struct
   4
   5     datatype place = P of int
   6
   7   datatype info = Info1 | Info2 | Info3
   8
   9   datatype 'a tr = TR of 'a exp * info | K of 'a -> int
  10        and 'a exp = SWITCH_I of ('a, int) switch
  11                   | SWITCH_S of ('a, string) switch
  12                   | STRING of string * 'a
  13        and ('a,'c) switch = SWITCH of 'a tr * ('c * 'a tr) list
  14
  15 datatype 'a pgm = PGM of string * 'a tr
  16
  17   type mulexp = place exp
  18    and multrip = place tr
  19   type mulexp_llv = (place*int) exp
  20    and trip_llv = (place*int) tr
  21
  22     fun llv(tr: multrip as TR(e,Info1)) : trip_llv =
  23       let
  24           val e' = llvExp e
  25       in
  26           TR(e',Info2)
  27       end
  28
  29     and llvExp(e: mulexp) : mulexp_llv =
  30       let
  31         fun llv_switch(SWITCH(e,branches)) =
  32           (* Note: e is trivial *)
  33           let val branches' = map (fn (c,e) => (c,llv e)) branches
  34           in
  35                SWITCH(llv e, branches')
  36           end
  37       in
  38       case e of
  39        SWITCH_I(switch) =>
  40           let val switch' = llv_switch switch
  41           in SWITCH_I(switch')
  42           end
  43       | SWITCH_S(switch) =>
  44           let val switch' = llv_switch switch
  45           in SWITCH_S(switch')
  46           end
  47       | STRING(s,place) => STRING(s, (place, 5))
  48       end
  49
  50
  51
  52     val  llv = fn (PGM (label,expression)) =>
  53       let
  54          val tr' = llv expression
  55       in
  56          PGM(label, tr')
  57       end
  58
  59 end
  60
  61