: (line) ( n -- ) 0 DO [char] - emit LOOP ;
: (_warning) ( n -- )  dup (line) space ." Warning" space (line) ;
: (warning-line) ( -- ) 30 (_warning) ;
: check-gforth ( -- )
  s" gforth" environment? IF
    s" 0.7.3" compare 0<> IF
      (warning-line) cr
      ." This code was developed for gforth version 0.7.3, "
      ." other versions may or may not work." cr
      (warning-line) cr cr
    THEN
  ELSE
    ." This code depends on gforth specific C FFI." cr abort
  THEN ;
check-gforth