I recently asked the following question:
Is swimming in 'swimming pool' gerund or present participle?
And you answered as follows:
In this case, the distinction is very clear!
'Swimming' here is an attributive gerund, since it denotes the purpose of the pool (not what the pool itself is doing).
I understood your explanation. However,our English teacher (whose native language is English) says that swimming in 'swimming pool' is not a gerund unless it's functioning as a noun! In 'Swimming is good exercise.', the underlined is a gerund as in 'waiting shed', 'reading room' etc. Is he right about his explanation?