Export to .txt

I would like to export all my workspace (even with the evaluation of
commands) to the text file.

Have you looked at .Rhistory? If you save your workspace when you quit a
session with R it's put in that file. You can always read it anywhere you
have a text editor.

   When I end work with more processing to be done, but it's repeating what I
did in the current session, I open a second buffer in emacs, load .Rhistory,
and use that to continue processing.

   This may do what you want.

Rich