If you are going to present grammar, then I would think it would be presented fully. Instead, what the traditional grammar presentation does is defer grammar points to footnotes in advanced readings. Here’s an example from a book on Norwegian written in 1912:
On page 248 of Second Book in Norse by J.A. Holvik note #2 states that “to get” is often used to connote necessity, “have to”.
Note #4 on the same page says the preposition “till” is used to denote possession.
I’m not saying that, to refer to language more commonly known to readers of this blog than Norwegian, that French “c’est a toi” or Latin “mihi est” or Russian “eto u men’a est’” need to be plugged into the first section on possessive adjectives and pronouns, but they are common enough to be included fairly early, in the elementary book, book one, or beginning book, whatever.
The same goes for alternative expressions of obligation like “have to”, “must” “got to” “need to”, etc. And I think it’s preferrable that all such usages be summarized in an appendix e.g. a summary of expressions of obligation or of possession.
One book that does this is Barker’s A Course in Urdu. It’s worth looking at just to see how he does this. One top scholar in the field of Urdu studies remarked to me that Barker tells you more than you ever need to know about Urdu. I said, “Thanks, but I’ll take Barker rather than just ’pick up’ all these alternatives.” My experience is that when fluent speakers of a language find that you only know “I have to go” and are puzzled by “I’ve got to go”, they just shrug and say something inane like, “Yeah, they mean the same thing.” Crap.
I know writers of pedagogical grammars are not writing a grammar manual but things as basic as common alternates in possessive and obligation expressions really need to be presented at some early point in the instructional process.
Needless to say (then why am I saying it?), none of this is necessarily an endorsement of pedagogical grammars for classroom use.