Eberon FOR..IN

FOR..IN loop statement is used to iteratate through arrays, STRINGs and MAPs. For arrays and strings all elements are iterated from the beginning to the end.

Syntax

FOR [key,] value IN array DO
    ...
END;

key is an optional variable standing for array/string's index (from 0 to LEN(array) - 1) or MAP's key. key type is INTEGER for arrays and strings and STRING for MAPs. value is a variable standing for element's value. These variables have no a separate declaration and their visibility scope is inside loop only. Also these variables are read-only - similar to non-VAR parameters.

Example

VAR
    a: ARRAY 3 OF BOOLEAN;
BEGIN
    FOR i, v IN a DO
        ASSERT(a[i] = v);
    END;

    (* not using key here *)
    FOR v IN a DO
    END;
END;

VAR
    m: MAP OF INTEGER;
BEGIN
    FOR k, v IN m DO
        ASSERT(v = 0);
        ASSERT(k # "");
    END;
END;