--------------------- How to add a refactoring to the editor interface -----------------

After having built a refactoring, in order to invoke the refactoring from the editor interface, 
you only need to modify the file:'GenEditorInterfaces.hs' from the 'editors' directory.

Next, we take the two refactorings :'swapping arguments' and "from if-then-else to Case" as examples 
to explain where and how to modify. Assume you are now ready to edit the 'GenEditorInterfaces.hs'. 

1) Swapping arguments. This refactoring is implemented in the module 'RefacSwapArgs' in file
   'RefacSwapArgs.hs'. The refactoring name is 'swapArgs', and is the only name exported by this
   module. 

Step 1. Find the definition of 'pfeRefactoringCmds'. In the right hand side, you can find a 
        do statement like: putStrLn $ unlines [ ... ]. Add ',"import RefacSwapArgs"  right 
        after the second-last element in the list. 

Step 2. Find the definition of 'cmds' which defines the menu structure. Add an entry for swapping
        arguments in an proper sub-menu, say 'Definitions' in this case, like this:

           editParameters "Swap Arguments" "swapArgs" 
           swapArgs $ fileName $ positionPar $ 
           comment "Swap the first two arguments of a function"

        where, "Swap Arguments" is what will appear in the menu menu, "swapArgs" again is the
        refactoring  name. This refactoring takes a file name and a position (lines number and
        column number) as parameters ('Par' means parameter).

Step 3. Add a top-level function named as 'swapArgs' (same as the refactoring name) including its 
        type signature to this module. This function just prints out some information about the 
        parameters. In the case for 'swapArgs', it can be like:

          swapArgs :: String -> Int -> Int -> IO ()
          swapArgs f l c = putStrLn $ ">swapArgs filename: " ++f++" line: "++show l ++" column: " ++ show c

Step 4. Go to the root directory of HaRe , say HaRe_19112004, and run: make.


Step 5. Reload the interface file for your editor (In emacs : M-x load-file editors/haskell-refac.el), you
        should be able to see the newly added entry in the Definitions sub-menu in the Refactor menu.

2). From If-then-else to Case.

    Follow the same steps as for swapping arguments. The only differences are in step 2 and 3.
 
    In step 2, when adding an entry to 'cmds', use 'regionPar' other than 'positionPar', as this 
    refactoring needs the user to highlight an area in the program source. So in the definition of 
    'cmds' you need to add:

        editParameters "From if to case" "ifToCase"
          ifToCase $ fileNamePar $ regionPar $
          comment "From it to case"


    In step 3, Corresponding to step 2, add the following function to the module. This function 
    takes four Int parameters which represent the start and end position of the highlighted area.

      ifToCase :: String ->Int -> Int -> Int -> Int -> IO ()
      ifToCase f ls cs le ce = putStrLn $
           ">from if to case: "++f
           ++" line: "++show ls++" column: "++show cs
           ++" line: "++show le++" column: "++show ce

Note: All the above code actually is already there, just has been commented out.