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What is RHELP?

   RHELP is a text-based help system that lets you easily build and
   maintain context-sensitive help files.  RHELP includes an Application
   Programming Interface (API) that lets you build help systems from the
   simple to the complex.  It provides all the necessary pieces so you
   don't have to do the nitty gritty work.

   The RHELP system consists of the RHELP compiler program (RHC.EXE)
   which builds the indexed help file from a text based source file.
   Also included is the RHELP de-compiler program RHDC.EXE which de-
   compiles a RHELP.HLP file into a source text file.  Finally a set of
   API functions are included that extract help information from an
   indexed help file based on a unique key value.  The RHELP compiler RHC
   compiles (indexes) a help source file into a single file which
   contains the help text along with a header containing an index.


   RHELP Source Code

   As with all RLIB components, the RHELP system comes with full source
   code included.  This includes the source code for RHC.EXE, RHDC.EXE
   and the API functions, which are included in the RLIB function
   library.


   Why Compile?

   Compiling a help source file with RHC results in a single runtime help
   file that contains both the index and the help text.  It is accessed
   with the Clipper low level file I/O functions.  However, you do not
   need to concern yourself with the low level file functions because all
   help information is retrieved via simple to use RLIB functions.  For
   example, to retrieve a block of help text associated with the key
   "EDIT SCREEN" from a help file named MYAPP.HLP, you only need to issue
   one function call; helpText = RH_TEXT("myapp.hlp", "EDIT SCREEN").
   Once the help text is retrieved you display it in your preferred way.
   An example of a help display function follows in the section entitled
   "An Example".


   Advantages

   The advantage of the RHELP approach becomes apparent when you try to
   create a help system for a product to be distributed, especially when
   it will run on a network.  Many Clipper developed help systems use a
   database file with memo fields to store help keys and text.  Using a
   .DBF file to contain help information has limitations.  First, the
   help text is usually contained in a memo file and the help database
   file is usually indexed into an index file.  This means that your help
   system now consists of three files; HELP.DBF, HELP.DBT, and HELP.NTX.
   Furthermore, you may wish to set the file attributes of help files to
   ReadOnly to protect from accidental overwrite or erasure.  Clipper and
   dBASE will not open a database file that is marked ReadOnly.  Clipper
   5.0 has just overcome this limitation with the READONLY clause to the
   USE command but Clipper Summer '87 still will not open a database file
   that is marked ReadOnly.  Because RHELP help files are accessed with
   the Clipper low level file functions, a ReadOnly attribute will not
   affect the ability to open these files.

   Another advantage of the RHELP approach over a .DBF file based help
   system is the fact that the source help text is maintained in a plain
   ASCII text file.  This file can be edited and maintained with your
   favorite editor or word processor which may include a spell checker
   and thesaurus.  With a .DBF file based help system you must either use
   dBASE or write a custom application just to enter or edit help text,
   not to mention that the editor in such a system may not be as
   desirable as some word processors.