immer VS clasp

I've been working on an editor (not text) in C++ and pretty early got into undo/redo. I went down the route of doIt/undoIt for commands but that quickly got old. There was both the extra work needed to implement undo separately for every operation, but also the nagging feeling that the undo operation for some operation wasn't implemented correctly.

In the end, I switched to representing the entire document state using persistent data structures (using the immer library). This vastly simplified things and implementing undo/redo becomes absolutely trivial when using persistent data structures. It's probably not something that is suitable for all domains, but worth checking out.

https://github.com/arximboldi/immer

How does this compare to https://github.com/arximboldi/immer (other than the C/C++ difference)?

Also, it's my understanding that, in practice, persistent data structures require a garbage collector in order to handle deallocation when used in a general-purpose way. How does your implementation handle that?

You might be interested in ewig and immer by Juan Pedro Bolivar Puente:

https://github.com/arximboldi/ewig

https://github.com/arximboldi/immer

See the author instantly opening a ~1GB text file with async loading, paging through, copying/pasting, and undoing/redoing in their prototype “ewig” text editor about 27 minutes into their talk here:

https://m.youtube.com/watch?v=sPhpelUfu8Q

It’s backed by a “vector of vectors” data structure called a relaxed radix balanced tree:

https://infoscience.epfl.ch/record/169879/files/RMTrees.pdf

That original paper has seen lots of attention and attempts at performance improvements, such as:

https://hypirion.com/musings/thesis

https://github.com/hyPiRion/c-rrb

You’re absolutely right, however people have been putting in the “extra efforts” required for efficiency. Check out immer if you’re interested.

The C++ immer library: https://github.com/arximboldi/immer

For C++ check this one out - https://github.com/arximboldi/immer

Yeah I agree that I should link that wikipedia page in the docs, I'll do that as soon as I get a chance. immer (https://github.com/arximboldi/immer) also links that page in its docs, for the exact same reason I'm sure. Interestingly, there is a lot of overlap between persistent data structures in the functional programming sense and persistent data structures in the persisted-to-disk sense because persistent data structures in the FP sense are one of the best ways to guarantee atomic updates and safe failure recovery in a persisted-to-disk system! Btrfs and ZFS, as well as many databases, are at their core basically just copy-on-write B+ trees.

I’ve never tried it, but I love the idea of implementing editor scene state using immutable data structures like https://github.com/arximboldi/immer With that, every edit would append a new node to a list of scene states. Undo/redo becomes iterating your view of the scene up and down through that list. Can’t screw up an undo function if there’s never any work to do :P

I have! I think it's related to the C++ immer library which I used several years ago in Vortex. It's kinda like the previous generation of ValueScript. 🍻

I accidentally a Common Lisp that interoperates with C++ (https://github.com/clasp-developers/clasp.git). We would also like to move beyond BDWGC and Whiffle looks interesting. I will reach out to you and maybe we can chat about it.

Clasp might be such a language, it seems.

https://github.com/clasp-developers/clasp

/u/jeaye are you aware of CLASP? https://github.com/clasp-developers/clasp https://www.youtube.com/watch?v=mbdXeRBbgDM

Sounds to me like CLASP; it automatically exports C++ objects to be used from Common Lisp also via llvm.

Now, the difference of compiling speed of SBCL and CCL is not so big. Look at cl-benchmark, LispWorks is really fast, CCL is on par with Allegro, SBCL is close to CCL. Or https://github.com/clasp-developers/clasp/wiki/Relative-Compile-Performance-of-clasp, it depends on specific project (SBCL sometimes faster, slower, alike), overall difference is not big.

So..

"Why do you want to make Lisp more popular? If you were sucessful, what would be different in the world, and why is that desirable to you?"

Normally at this point I'd listen to the response, and ask more questions based on that. That would wind up with a very, very deep thread, so I'll break a cardinal rule and pre-guess at some answers.

This kind of question comes up pretty frequently. In many cases, I suspect the motivation behind the question is "Wow! Here's this cool tool I've discovered. I want to make something really useful with it. I want to do it as part of a community effort; share my excitement with others, share in their excitement, and know that what I'm making is useful because others find it desirable and are excited by it." The field could be cooking, sports, old machine tools, tiny homes, or demo scene. Its the fundemental driver for most content on HN, YouTube, Instructables, and such. It is a Good Thing.

If that is your motivator, then my suggestion is to find something that bugs you and fix it. You've already decided you're only interested in code, not other aspects. You said you preferred vim, but the emacs ecosystem has a very rich set of sharp edges that need filing off, and a rich set of tools with which to attack them.

One example: even after 50 years there's no open IDE which allows you to easily globally rename a Lisp identifier. I don't know about LispWorks or other proprietary environments, but you can't in emacs or vim do a right-click on "foo" in "(defun foo ()...)" and select a command which automatically renames it in all invocations. [Queue lots of "but you can..." replies here.] I don't think vim is up to the task of doing this internally. It would be possible in emacs; but would require a huge effort with lots of help from other people. If you emerged alive from that rabbit warren you'd join the company of Certified "How Hard Could it Be?" Mad Scientists such as Dr. "I just want to draw molecules" Meister [1] and "Wouldn't an OS in Lisp be Cool" Froggey [2].

[1] https://github.com/clasp-developers/clasp

[2] Mezzano https://github.com/froggey/Mezzano

But also, there's a reason why most implementations readily make an effort to provide interoperability tools with a variety of runtimes. Clasp much like ABCL gives access to a whole library of other libraries trivially wrapped to interoperate with at little to no performance to cost (depending on how thin you make the wrappers, mainly).