What does Lem have over Emacs ?

[kissthemagpies]

hello! i recently came across this project and found it very interesting on paper.

but, i'd like to know what reasons pushed the contributors to develop Lem instead of Emacs.
is it the reliance on Common Lisp, as opposed to Emacs Lisp?

im not a lisp programmer (nor a huge programmer atm, admittedly), so likely i am missing something.
that is all for me, i hope you are all well and cheers :).

[vindarel]

Hello and welcome,

From what I gather, a strong motivation, if not the main one, for Lem's creator (cxxxr and the other japanese early contributors), was to build an editor "well tuned for Common Lisp". "After you install Lem, you can start developing in Common Lisp at once" was a moto.

cxxxr isn't fond of GNU Emacs, and absolutely doesn't mean to copy it.

Emacs is of course the best or second best editor for Common Lisp, but it doesn't give you an out-of-the-box experience: you must install the Lisp implementation (SBCL), the client-side IDE (Slime/Sly), and configure it a bit. With Lem you're ready.

And you can extend Lem in Common Lisp. CL is a very very, very cool language, superior to elisp, industrial-grade, that you can use in many fields, in the real world.

Now as of today Lem has some unique capabilities. It has a SDL2 interface which allows it to display graphics and games; it ships a LSP client (ok now Emacs does), Lem's markdown mode is a bit interactive (live preview, major mode with highlighting and all keyboard shortcuts in code blocks), Lem's completion pop-up is nicely visual and interactive out of the box, Lem as the "watch" function that displays evaluation results on the fly, in overlays; when you call ls in the Lisp REPL and you get a list of files: those lines are actually interactive with directory-mode bindings (think multiple-major modes), you can have a transparent background, and a few more things for Lisp development (see the common lisp documentation page).

Lem is 100% CL code, SBCL is mainly CL (and a bit of C), Emacs is a lot of C. In Lem and CL you can jump to the (lisp) definition of many, many built-ins. It's incredible to explore and debug a codebase.