Page 221 - Practical English Usage 3ed - Michael Swan, Oxford

We're going to get a new car soon.
John says he's going to phone this evening.
When are you going to get your hair cut?
I'm going to keep asking her out until she says 'Yes'.
I'm going to stop him reading my letters if it's the last thing I do.
3 things that are on the way: She's going to have a baby
Another use of the going-to structure is to predict the future on the basis of present evidence - to say that a future action or event is on the way, or starting to happen.
Sandra's going to have another baby in June.
Look at the sky. It's going to rain. Look out! We're going to crash!
4 commands and refusals
Going to ... can be used to insist that people do things or do not do things. You're going to finish that soup ifyou sit there all afternoon!
She's going to take that medicine whether she likes it or not!
You're not going to play football in my garden.
It is also used in emphatic refusals.
I'm not going to sit up all night listening to your problems!
5 gonna
In informal speech, going to is often pronounced /gana/. This is sometimes shown in writing as gonna, especially in American English.
Nobody's gonna talk to me like that.
For /LIas going to, has been going /0 etc, see 221.
For going to ... compared with the present progressive. see 214.2. For a comparison with will. see 216.
214 future (4): present progressive
1
present reality: I'm washing my hair this evening
We use the present progressive for future actions and events that have some present reality. It is most common in discussions of personal arrangements and fixed plans, when the time and place have been decided.
What are you doing this evening?'"I'm washing my hair. I'm seeing Larry on Saturday.
We're travelling round Mexico next summer.
Did you know I'm getting a new job?
What are we having for dinner?
My car's going in for a service next week.
We often use the present progressive with verbs of movement, to talk about actions which are just starting.
Are you coming to the pub?
I'm just popping out to the post office. Back in a minute. Get your coat on! I'm taking you down to the doctor!
Note that the simple present is not often used to talk about the future (see 215).
What are you doing this evening? (NOT What dO}'6lt tltJ this elltming?) • page 189
future (4): present progressive 214