References

In addition to pointers, Spice supports references. Under the hood, this works with non-nullable pointers.

Usage - local variables¶

References can not be declared without initializing. Only declaring with immediate initialization is valid:

1
2
3
4

int variable = 123;
int& variableReference = variable;
variableReference++;
printf("%d", variable); // Prints 124

Whenever an assign operator is applied to the reference, not the reference is mapped to a new variable. Instead, the referenced value gets assigned. Therefore, the reference itself can only be assigned once, namely at declaration.

Usage - function parameters / return types¶

References can be used as function parameters and return types. This is useful for passing large objects without copying them:

 1
 2
 3
 4
 5
 6
 7
 8
 9
10

type LargeStruct struct { /* many large fields */ }

f<LargeStruct&> returnSelf(LargeStruct& s) {
    return s;
}

f<int> main() {
    LargeStruct s;
    LargeStruct& s2 = returnSelf(s);    
}

Usage - struct fields¶

Struct fields can also be of type reference:

1
2
3
4
5
6
7
8

type T dyn;
type A<T> struct {
    T& data
}
f<int> main() {
    double d = 23.456;
    dyn a = A<double>{d};
}