Enhanced "inputdialog()" as for input mechanisms of i_CTRL-N, z= etc.

[Suresh Govindachar]

Hello,

  I know about inputdialog() for getting user input from 
  within VimL.  My question is how to access the user-input 
  mechanisms used by i_CTRL-N, z=, i_CTRL-X_CTRL-S etc. 
  from within VimL?

  Thanks,

  --Suresh