ΜOpal: Unterschied zwischen den Versionen
K (wikipedia-link) |
K |
||
| Zeile 4: | Zeile 4: | ||
<pre> | <pre> | ||
DEF fac(X:nat):nat == | DEF fac(X:nat):nat == | ||
| − | + | IF eq(X,0) THEN | |
| − | + | 1 | |
| − | + | ELSE | |
| − | + | mul(X, fac(sub(X, 1))) | |
| + | FI | ||
| + | |||
DEF MAIN:nat == | DEF MAIN:nat == | ||
| − | + | fac(8) | |
</pre> | </pre> | ||
Version vom 21. Februar 2006, 02:53 Uhr
Eine simple Programmiersprache zu der in der Lehrveranstaltung PSS ein Compiler geschrieben wird.
Beispielprogramm:
DEF fac(X:nat):nat ==
IF eq(X,0) THEN
1
ELSE
mul(X, fac(sub(X, 1)))
FI
DEF MAIN:nat ==
fac(8)
EBNF:
Prog -> Def Def* "#"
Def -> "DEF" Lhs "==" Expr
Lhs -> "MAIN" ":" Type
| "id" "(" [ "id" ":" Type ( "," "id" ":" Type )* ] ")" ":" Type
Type -> "nat"
| "bool"
Expr -> "number"
| "true"
| "false"
| "id" [ "(" [ Expr ( "," Expr )* ] ")" ]
| "IF" Expr "THEN" Expr [ "ELSE" Expr ] "FI"