rules and macro query

[Payal]

Hello all,
I have a few simple doubts. Can someone help with them, please?

1. In target specific variables, how can I define multiple vars. Is
this the only way,
X : a=foo
X : b=bar

2. How to define a target specific macro (with define)? This does not
work.
$ cat -vet Makefile
aaa : define foo$
hi foo$
endef$
$
aaa :$
^Iecho $(foo)$
$

3. A silly query. In a rule, after target : prereq. can only these
things come,
a. a shell command (after a hard tab)
b. a make comment

Can't we give "make" variables or functions there? If yes, can someone
give simple example or two please?

With warm regards,
-Payal
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