I want to go against the idea that Grammar is language and that grammar is more than tricky familiarity with the puzzling rules.

None ever told me that there are 29 different types of base-sentences referring to Present Past or Future. It is these that we give them different forms and use in our writing and speaking. I usually divide them in 10+10+9 respectively.

My way of understanding them is very simple i.e. to refer to future (an action about which we are talking for the first time and that action has not yet taken place) I should simply go on using will or shall.

Basically there are only Seven Golden Principles of English that none should run against them if anyone he or she means to master the skill in the use of English language.