;+
;
; @file_comments
; display an ASCII file in a widget.
; It is the same thing that <proidl>XDISPLAYFILE</proidl> but here, we use it
; to display the content of a procedure or of a function located in the !path
; ".pro" suffix will be appended if needed.
;
; @categories
; Utilities Widget
;
; @param FILENAME {in}{required} {type=scalar string}
; It is the name of the procedure or of the function
; we want to display (with or without .pro at the end).
; FILENAME should be located in !path.
; ".pro" suffix will be appended if needed.
;
; @keyword _EXTRA
; Used to pass keywords to <proidl>XDISPLAYFILE</proidl>
;
; @restrictions
; Triggers the <proidl>XMANAGER</proidl> if it is not already in use.
;
; @examples
; IDL> xfile,'plt'
;
; @history
; Sebastien Masson (smasson\@lodyc.jussieu.fr)
; 7/1/99
; 6/7/1999: compatibility mac and windows
;
; @version
; $Id$
;
;-
;
PRO xfile, filename, _EXTRA = ex
;
  compile_opt idl2, strictarrsubs
;
  usage="xfile, filename, _EXTRA = ex"
;
; check parameters
  check_param = N_PARAMS()
  if (check_param EQ 0) then begin
     dummy = report(['No input parameter', $
                     'Usage : ' + usage])
     return
  endif
;
; check arguments
  if arg_present(filename) then begin
     dummy = report(['No input parameter filename', $
                     'Usage : ' + usage])
     return
  endif
;
; Are we sure filename is a string?
   intype = size(filename, /type)
   if intype NE 7 then begin
      dummy = report(['Input parameter filename type : ' + size(filename,/TNAME) , $
                      'Input parameter filename must be a string'])
      return
   endif
;
; find the file and display it!
   pfile = find(filename, /first_found)
   if (pfile NE 'NOT FOUND') then begin
     xdisplayfile, pfile[0], _EXTRA = ex
   endif else begin
     dummy = report(['Input parameter filename : ' + filename, $
                     filename + ' does not exist ...'])
   endelse
;
   return
end