Useful Emacs tools for working with RPL source code, the native
language of HP48/49/50-series calculators.

In its present state really only provides `sysrpl-mode' for editing
SysRPL source files.  This mode implements syntax highlighting and
documentation lookup, using data extracted from Carsten Dominik's
``entries.db'' system RPL entries database[1].

To install rpl-tools, clone the Mercurial repository to somewhere in
your Emacs `load-path' with

  hg clone

then add the following to your ~/.emacs file

  (require 'rpl-tools)
  (add-to-list 'sysrpl-mode-hook 'eldoc-mode)

where the latter command activates the minor eldoc-mode in
sysrpl-mode.  This causes a stack-effect diagram to be displayed in
the minibuffer whenever the cursor is on a SysRPL word.

More info can be displayed with the `sysrpl-apropos-thing-at-point'
command, bound to C-c C-a by default, which pops up another window
with any extra information available for the supplied word (by default
the one under the cursor).

Note: sysrpl-mode is not bound to any particular file extension by
default, so to enable it for any particular buffer you will have to
issue the command

  M-x sysrpl-mode

to place the current buffer into sysrpl-mode.  Alternatively you can
use the standard Emacs file local variable feature to embed the mode
name into the first line of a file.  See the included example in
examples/timedone.s for details.

Also, be aware that this code was written with Gnu Emacs 24.3 so I may
have used features not found in earlier versions.  If you see strange
errors when you try to use it, check your Emacs version with

  M-x emacs-version

and be prepared to upgrade your Emacs if necessary.


[1] Carsten Dominik's SysRPL entries database

Paul Onions
3 May 2015