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# Gypsum: my clone of Emacs and ELisp written in Scheme
Ramin Honary (he/him) - <mailto:ramin.honary@gmail.com>
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I would like to demonstrate an Emacs clone I have been
writing in Guile Scheme for the past year, which I am
tentatively calling "Gypsum". Unlike other editors which
only clone the Emacs keybindings (Edwin, Jed, jEdit, Jove,
Lem, MG, Yi, Zile), I hope my Emacs clone will also fully
clone the Emacs Lisp programming language well enough that
many of the packages in ELPA, Non-GNU ELPA, and perhaps even
MELPA, can be used in "Gypsum" without any modification. I
would also like to talk a little bit about the how I am
implementing it (the software architecture), and invite
others to contribute.
I think my project is of interest to many Emacs users
because, firstly, I have personally spoken with a relatively
large number of people who have expressed interest in making
Emacs programmable in Scheme. Secondly, there is a good
amount of prior art for Scheme implementations of
Emacs. There are even builds of Emacs that link to Guile
which provides a "scheme-eval" built-in function that
translates between Elisp data types and Scheme data
types. The Guile compiler itself ships with an Emacs Lisp
compiler as well, although it does not provide enough of
Emacs's built-in functions to be of much use.
So by using Guile, we can make use of a lot of the prior
art, in fact I am currently using the tokenizer and reader
used in Guile's built-in Elisp interpreter to implement
"Gypsum's" Elisp interpreter. That said, I have gone out of
my way to make my code fully R7RS compliant, so I hope I can
port it to other Scheme implementations like MIT Scheme,
Gambit, Stklos, and perhaps Chez Scheme with Gwen Weinholt's
R7-to-R6RS translator. I consider the Guile version of
Gypsum to be the reference implementation of what I hope
will become a fully cross-platform programming language and
text editor written in portable R7RS Scheme.
The reference implementation of "Gypsum" is a GUI
application based on Gtk using a library called
"Guile-GI". Guile-GI uses the GObject Introspection
framework to automatically generate Scheme language bindings
to libraries like Gtk and Glib which are written in the C
programming language. There is not yet any terminal-emulator
version of "Gypsum."
The next step of the project will be to implement enough of
Elisp that we can run tests written in the Emacs Regression
Testing (ERT) framework. We can then incorporate the
original GNU Emacs regression test suite into Gypsum. Any
new API added to Gypsum Elisp will most likely already have
regression tests we can use to make sure it is working in a
way that is compatible with GNU Emacs Lisp. I would like to
make it as easy as possible for people to contribute to this
project, and having a list of APIs to be implemented each
with a set of regression tests the APIs are expected to
pass, is a very good way to do that.
About the speaker:
My name is Ramin Honary, I have been a professional software
engineer of 16 years, lately mostly doing full-stack
software development. I have always been fascinated with
programming languages, and especially functional languages
like Lisp and Haskell. I have been using Emacs
since 2017. But lately it is with Scheme that I have been
spending most of my free time. I am only a Scheme
programming enthusiast, I am not involved with Scheme
professionally.
You may also like another talk by this speaker:
[EmacsConf - 2022 - talks - Build a Zettelkasten with the Hyperbole Rolodex](https://emacsconf.org/2022/talks/rolodex/)
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