files/practicum/RefactorX.icl

   1 implementation module RefactorX
   2
   3 import StdEnv
   4
   5 Start = map toString [E1,E2,E3,E4,E5]
   6
   7 E1 = (let x = 42 - 3 in x / 0) + (let y = 6 in y * y)
   8 E2 = let x = 42 in x + (let x = 58 in x)
   9 E3 = let x = 1 in let y = 2 in let x = 3 in 4
  10 E4 = let x = 1 in x + y
  11 E5 = (let x = 1 in x) * x
  12
  13 ::      Expr                                                    = NR   Int
  14                                                                         | VAR  Name
  15                                                                         | OP   Expr Operator Expr
  16                                                                         | LET  Name     Expr Expr
  17 ::      Name                                                    :== String
  18 ::      Operator                                                = PLUS | MIN | MUL | DIV
  19 ::      Val                                                             = Result Int | Undef
  20
  21 //  expressies afdrukken:
  22 instance toString Expr where
  23         toString ...
  24
  25 //      vrije variabelen:
  26 free                                                            :: Expr -> [Name]
  27
  28 //      verwijder deelexpressies met ongebruikte let-variabelen:
  29 remove_unused_lets                                      :: Expr -> Expr
  30
  31 //      evaluator met tabel van naam-waarde paren:
  32 eval                                                            :: Expr -> Val