func sumList()

in lib/collections.go [1053:1091]

• 38 lines of code
• 9 McCabe index (conditional complexity)

func sumList(arg ref.Val) ref.Val {
	list, ok := arg.(traits.Lister)
	if !ok {
		return types.NoSuchOverloadErr()
	}
	if list.Size() == types.IntZero {
		return types.NewErr("no sum of empty list")
	}

	var (
		iSum             int
		fSum             float64
		hasInt, hasFloat bool
	)
	it := list.Iterator()
	for i := 0; it.HasNext() == types.True; i++ {
		elem := it.Next()
		switch elem := elem.(type) {
		case types.Double:
			if hasInt {
				return types.NewErr("no sum of mixed int and double: first mismatch at index %d", i)
			}
			hasFloat = true
			fSum += float64(elem)
		case types.Int:
			if hasFloat {
				return types.NewErr("no sum of mixed int and double: first mismatch at index %d", i)
			}
			hasInt = true
			iSum += int(elem)
		default:
			return types.NewErr("no sum of list containing %T", elem)
		}
	}
	if hasInt {
		return types.Int(iSum)
	}
	return types.Double(fSum)
}