How to modify PROMPT to include variables?

Question

Here is a simplified version of what I need... if I set a variable and set it as my PROMPT, like this:

set myvar=AAA
PROMPT %myvar%$g

gives me:

AAA>

but then, I want to change my variable and consequently the prompt, so:

set myvar=BBB

should produce as my PROMPT:

BBB>

but, it is still

AAA>

How do make it dynamic?

Answer 1

There is no way to directly do that; however, you may easily get an equivalent result if you write your own "shell". For example:

@echo off
setlocal

:loop
   echo/
   set "command="
   set /P "command=%myvar%>"
   call %command%
goto loop

Output example:

>set myvar=AAA

AAA>echo %time%
14:42:12.32

AAA>set myvar=BBB

BBB>echo %date%
10/12/2015

BBB>exit