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
33
34
35
36
37
38
39
40
41
42
43
44
45
46
|
package regtest.basic;
/** Tests higher order functions */
<T, U> U apply(T->U f, T x) = f(x);
<T, U> U apply2(T->U f, T x);
apply2(f, x) = f(x);
class High
{
alike high( ()->void );
String->void fieldFunction;
}
high(h@High, f) { f(); return h; }
void test_parsingExp(High h) = (h.fieldFunction)("");
void test_parsingStmt(High h)
{
(h.fieldFunction)("");
}
void test_higher_order()
{
println(id("ID"));
println((<T>(T x)=>x)("LAMBDA"));
println(apply(<T>(T x)=>x, "LAMBDA"));
println(apply(nativeToString, "Using native methods as first class values"));
println(apply(id(intIdentity), 42));
}
String nativeToString(String) = native String Object.toString();
int intIdentity(int x) = id(x);
// Using int -> long implicit conversion in the returned value
long intWidening(int x) = x;
void unboundVariable(String v)
{
throw new Error();
}
void passAsValue() = println(unboundVariable);
|
