Multiple Values

Compile-time operations over multiple-value lists. A multiple-value list is the sequence of values produced by a variadic argument, a comma expression, or another primitive. These primitives let you select, count, and slice such lists at compile time. None may be overloaded.

countValues

[..xs]
countValues(..xs) : Int32;

The number of values in ..xs is available as an Int32 via countValues.

nthValue

[n, ..xs when n >= 0 and n < countValues(..xs)]
nthValue(#n, ..xs);

To pick a single value out of a list by position, use nthValue. Positions are zero-based.

withoutNthValue

[n, ..xs when n >= 0 and n < countValues(..xs)]
withoutNthValue(#n, ..xs);

To drop one value from a list by position, use withoutNthValue. It returns all values of ..xs except the one at position n, in order.

takeValues / dropValues

[n, ..xs when n >= 0]
takeValues(#n, ..xs);
dropValues(#n, ..xs);

takeValues returns the first n values of ..xs. dropValues returns everything after the first n. Both clamp n to the list length, so asking for more values than exist is not an error.

integers

[n when n >= 0]
integers(#n);

integers produces runtime integer values from 0 to n - 1, typed as Int32 or SizeT to match the type of n. When n is 0, it produces no values.

Typical use with ..for:

..for (i in integers(#5))
    a[i] = x;

staticIntegers

[n when n >= 0]
staticIntegers(#n);

staticIntegers works like integers, but each value is a static integer (#0 through #(n - 1)).

Use this when the index itself needs to be a static value, for example with tupleRef or staticIndex:

..for (i in staticIntegers(#3))
    println(tupleRef(t, i));