func()

in src/ct/parser/tree.go [277:352]

• 57 lines of code
• 16 McCabe index (conditional complexity)

func (n *Node) EvalRelation() (*relation.Relation, error) {
	r := relation.New()

	left := n.left
	right := n.right

	if left.val != "V" {
		left, right = right, left
	}
	if left.val != "V" {
		return nil, fmt.Errorf("bad or missing variable node: %s, %s", left.val, right.val)
	}

	r.Name = left.EvalVariable()
	r.ID, _ = variables.Get().ID(r.Name)

	// Check that the attribute node A exists:

	if right == nil || right.val != "A" {
		return r, nil
	}

	m := right

	r.Unit = m.EvalUnit()

	// Check the left branch of A:

	setBound := func(b *relation.Limit, lower bool) {
		switch {
		case lower:
			if r.Lower == nil {
				r.Lower = b
			}
		case !lower:
			if r.Upper == nil {
				r.Upper = b
			}
		}
	}

	left = m.left

	switch left.val {
	case "E":
		nums := m.EvalNums()
		r.Value = nums
		return r, nil
	case "B":
		b, lower := left.EvalBound()
		setBound(b, lower)
	case "L", "Y":
		r.Lower = left.EvalRange()
	}

	// Check the right branch of A:

	right = m.right

	if right == nil {
		return r, nil
	}

	switch right.val {
	case "W":
		b, lower := right.right.EvalBound()
		setBound(b, lower)
	case "B":
		b, lower := right.EvalBound()
		setBound(b, lower)
	case "Y":
		r.Upper = right.EvalRange()
	}

	return r, nil
}