Method push

dql/math.go:24–24

(t *MathTree)

func (s *mathTreeStack) empty() bool      { return len(s.a) == 0 }
func (s *mathTreeStack) size() int        { return len(s.a) }
func (s *mathTreeStack) push(t *MathTree) { s.a = append(s.a, t) }

func (s *mathTreeStack) popAssert() *MathTree {
	x.AssertTruef(!s.empty(), "Expected a non-empty stack")