Elida

“Correct me if I'm wrong.”

OK. You're wrong, Elly.

Elida

“The examples above are a bit strange actually.”

I would say they seem "strange" to you simply because the usage is new to you.  The fact that a usage is new to you does not automatically mean it is grammatically incorrect.

You'd benefit if you tried to understand what Jim has written here.  The fact that you "don't hear much about these forms" is an indication that you still have a lot to learn about English -- any kind of English.  Jim's posts here have had nothing to do with slang.  The usage he wrote about here is neither "liberal" nor "lazy" English.  What in the world does "not pure" mean?  To be perfectly honest, you seem to equate the word "pure" with beginner level grammar -- i.e. overly simplified grammar rules.

Elida

“i'll write you when you'll get there”

As regards the second sentence in your first post (supposedly uttered by an Australian), it is not a sentence I would normally expect to hear any native speaker use.  However, it is also not correct to simply say that "will" can never follow "when".  I don't speak Australian English, and I don't know the broader context of the sentence you quoted.  In fact, I don't know whether the sentence was even correctly quoted.  However, I'd say the grammatical "correctness" of it could possibly depend on the broader context.  The use of will (you'll) could be grammatically justified this way, for example:

You are planning to visit someone and that person is taking care of arranging some things for you locally. After the person has finished making the arrangements, he is going to send you an e-mail with the details.  Perhaps an important detail is this: probable time of arrival.  "I'll write you when you'll get there" could have been used to mean this:

- I will write you an e-mail that will provide you with an answer to the following question:  "When will I get there?"

Elida

“It's kind of a "liberal" and "lazy" English, so it's obvious to get surprised to these ways of using some words obviously you can be surprised by some of the ways words are used.
”

Elida

“Other than that, there are some grammatical rules which aren't used in a daily speaking. ”

The use of the indefinite article ("a") is grammatically incorrect.  The statement is also incorrect.  You might say, however, that formal grammar rules are sometimes ignored in informal English.

CalifJim

“There is a shade of "requirement before result" in all the examples you cite.  It is almost a conditional formula.”

Hmm, this is confusing! This means the "rule" that says "don't use will after before, after, until, when, etc." just doesn't take some contexts into account.
I think I understand what those structures imply, but I think I would tend to use "to be going to" in those cases, instead of will. But maybe this "special usage of the future tense" is only used after "before", and not after other particles like "until" and "when".

If I got it right, you are saying they are used this way:

We're going to have to turn off all the lights before he'll leave. = We will have to do something before we get to a state where we can say something else will happen (it is possible for something else to happen).

And for that meaning, I would tend to use "going to" (don't ask me why):
We'll have to turn off all the lights before he's gonna leave. <--- Is this acceptable in American English? (...before he reaches a state when he's about to leave)

In any case, I would recognize such structures as "special structures" with a special meaning, as you said... a kind of "modal". If so, is it only possible before the particle "before"? In theory, it might work with "unless", "until", etc. too. But I am afraid it doesn't work that way.

Thanks.

CalifJim

“

Kooyeen

“the "rule" that says "don't use will after before, after, until, when, etc." just doesn't take some contexts into account. ”

Right.  It doesn't.  That rule is often given in elementary texts without the details so as not to confuse students with a list of exceptions that are not even going to occur within the rest of the textbook they are using.

”

 

hm...though I've been studying english for more than 12 years now, and  I knew the rule that Kooyeen was talking about, I still find it hard to accept these exceptions. :)
anyway, that's my problem.

Elly.

p.s. the only form, acceptable for me would be : "We will have to be there, before the rain starts.."

Kooyeen

“We're going to have to turn off all the lights before he'll leave.”

Hi Kooyeen
One thing to also keep in mind here is that "will" is quite commonly used when referring to "willingness". In the sentence above, I would interpret "before he'll leave" as meaning "before he is willing to leave".

I agree with Jim completely about grammar books.  What you find in ESL grammar books is limited, and the lower the level, the more simplistic they are.  Simplified grammar rules work in many cases, but they by no means work in all cases.