       commandloop ?prompt1? ?prompt2?
              Create  an interactive command loop for the current
              TCL interpreter.  This  command  receives  commands
              from  stdin  and  executes  them.  It is useful TCL
              scripts that do not normally converse interactively
              with  a user through a Tcl command interpreter, but
              which sometimes want to enter this mode.

              Prompt1 is a Tcl command string that  is  evaluated
              to  determine  the  text of the prompt string.  The
              old value of tcl_prompt1 is saved and it is set  to
              this  value  for  the duration of the command loop.
              Prompt2 is a command string that  is  evaluated  to
              determine  the  ``downlevel  prompt'', which is the
              prompt which is issued for continuation input.  The
              old  value of tcl_prompt2 is saved and it is set to
              this value for the duration of the command loop.

              When the command terminates, the variables for  the
              prompt  hooks  will  be set to their old value.  If
              these arguments are not specified, the prompt hooks
              use their current value.  Prompt hooks are TCL code
              that return as their result the prompt  to  output.
              The result of the last command executed in the com-
              mand string (which may be a return) will be used as
              the prompt.

              This command is provided by Extended Tcl.
