Provide repl mode for my package

I want to provide a REPL mode for my package. I’m looking for help to set it up. I’ve looked at RCall.jl but it’s too complicated for me to understand. Also Pkg.jl, there’s too much stuff for me to understand. here is what I want:

  1. Upon loading my package, there is a new mode provided that one can activate with a certain key. I kind of get how that works, but any hints much appreciated.
  2. once in side the special new mode, one can type the name of a function, which then gets called and returns whatever it returns. Very much like like Pkg.jl but much simpler I guess:
myprompt> fun1
--> calls fun1() and returns

myprompt> fun2
--> calls fun2() and returns

myprompt> fun1 x
--> calls fun1(x) and returns