return true
			}
		}
		return false
	case OpAnyCharNotNL:
		return r != '\n'
	case OpAnyChar:
		return true
	}
	return false
}

// parseVerticalBar handles a | in the input.
func (p *parser) parseVerticalBar() {
	p.concat()

	// The concatenation we just parsed is on top of the stack.
	// If it sits above an opVerticalBar, swap it below