blob: a2b56141395e5bd33115afd0baf6fe80ede53965 (
plain) (
blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
|
implementation module RefactorX
import StdEnv
Start = map toString [E1,E2,E3,E4,E5]
E1 = (let x = 42 - 3 in x / 0) + (let y = 6 in y * y)
E2 = let x = 42 in x + (let x = 58 in x)
E3 = let x = 1 in let y = 2 in let x = 3 in 4
E4 = let x = 1 in x + y
E5 = (let x = 1 in x) * x
:: Expr = NR Int
| VAR Name
| OP Expr Operator Expr
| LET Name Expr Expr
:: Name :== String
:: Operator = PLUS | MIN | MUL | DIV
:: Val = Result Int | Undef
// expressies afdrukken:
instance toString Expr where
toString ...
// vrije variabelen:
free :: Expr -> [Name]
// verwijder deelexpressies met ongebruikte let-variabelen:
remove_unused_lets :: Expr -> Expr
// evaluator met tabel van naam-waarde paren:
eval :: Expr -> Val
|
