An O(x)Caml book that runs

aanirudh24seven 3 days ago 12 commentsRead Article on kcsrk.info

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UncleOxidant•43 minutes ago

> So the later modules embed a full 32-bit Alpine Linux machine that boots inside the browser tab, using the v86 x86-to-wasm emulator... You are running OCaml bytecode inside a Linux guest inside an x86 machine emulated in WebAssembly, several layers of emulation deep

Wow, this is wild!

> The thing I would love to reach is booting a compiled unikernel directly in wasm via WASI, with no Linux host underneath at all. That would make the last module as live as the rest.

Couldn't the Mirage unikernel thingy be used to compile a unikernel with all of the needed OCaml libs + i/o support? Thus negating the need for having to boot Linux inside of a browser tab? Couldn't that be done in all of the places they're booting Linux in a tab?

kcsrk•10 minutes ago

Author of the post here.

I need a Linux VM to illustrate a couple of things in the last few lectures. Showing C undefined behaviour, memory safety issues and how that becomes security issues, compiling OCaml program to show test coverage, and being able to build unikernels. So can’t completely do away with Linux VMs.

For Unikernels, currently v86 is 32-bit only and OCaml 5 has dropped support for native 32-bit backends. In order to boot 64-bit unikernels, I’d need qemu. All of this could be done, but (a) this is likely to be quite slow (and the current emulation already is) and (b) the learning objectives are probably not improved a lot with the additional infrastructure. Hence, dropped it.

belmarca•about 2 hours ago

Hey, this is super interesting! We have been working on a quite similar system over the past few years at Université de Montréal. We develop and use codeBoot (https://codeboot.org) to teach introductory programming courses there. We also wrote an executable book for teaching a Cegep course (think last year of high school in the US). You can find it here (https://420-sn1.codeboot.org/) but mind you, the English version is not completed past chapter 1. The book was written in French.

Our tech stack is different but the choices we made are quite similar. Multi-tiered platform, markdown for authoring, executable exercises, teacher platform to produce, give, receive and grade homework/exams, etc. A distinguishing characteristic is that codeBoot's Python interpreter (pyinterp) allows single-stepping through the code. That's quite useful for teaching and studying.

We have a few exciting features coming up and we're working on a proper landing page and clean English translation for the book. If anybody is interested to learn more, reply here or contact me (email in my profile). I'd love to connect with educators, students or hackers alike!

kcsrk•3 minutes ago

Super interesting. Thanks for sharing.

I have used Jupyter notebooks with a Docker deployment in my prior courses for OCaml and Prolog, with support for auto grading (using nbgrader). Jupyter notebooks aren’t great for version control. Otherwise, it worked pretty well across multiple iterations of the course with new professors coming in and independently being able to use the infra.

quibono•about 4 hours ago

> The single biggest obstacle a beginner hits with any language is not the conceptual understanding. It is the install.

Is that _really_ the case? I find it very unlikely (not just in an OCaml context).

belmarca•about 2 hours ago

Yes, definitely the case. Just imagine a class with 100 students, each with a system that has its own quirks (OS, browser, and a mix of versions, etc). We built codeBoot (https://codeboot.org) specifically for this reason!

charcircuit•about 1 hour ago

In my experience you can just tell AI to install it and it will figure out all of those quirks on its own.

QuadmasterXLII•about 4 hours ago

I remember this being true for me, a long, long time ago. There was something like a four year gap between me being able to munge linked lists in TiBasic and me being able to reliably install java and compile System.out.println(“hello world”)

penteract•about 3 hours ago

Yes for me (although difficulty varies depending on what you're trying to install). I would have started programming 2 years earlier than I actually did if my first attempt to install tools to run a programming language had worked.

You have to precisely follow a sequence of instructions without the experience to understand their purpose, or any idea of how to fix things if you make a mistake.

Web technology is an exception to this. People already have a web browser, and ignoring mobile devices, browsers come with a js REPL.

ladax72707•about 3 hours ago

You don't get to hit other obstacles if you don't have the ability to run the code and play with it.

TylerE•about 1 hour ago

Yes. The reason I ended up being a python dev is that way back in the day there was a free, easy installer that ran on my machine, including a functional if basic IDE with syntax highlighting. This was Python 1.5 on a Mac Classic. Even getting a C compiler would have been a major lift, this was in the modem days so downloading was always an adventure.

WillAdams•about 2 hours ago

Interesting next step for Literate Programming.