CakeML
Offline compiler explorer
The greatest liability of the original and 2017 compiler explorers is that they depended on server code and therefore became unusable after the server code was no longer maintained - you could not simply check out an old version and test it. While I believe the server code was checked in, it had different dependencies from the client code and was prohibitively difficult to configure when I attempted to do so several years ago.
Instead I propose to run the CakeML compiler in the browser. In the mid-term future the ideal way to do that would be the wasm backend, but in the immediate term I propose to load a riscv compiler binary and run it with a javascript or wasm riscv emulator, of which there are several. The current riscv compiler binary is 18 MiB and requires 21 MiB of heap and 2 MiB of stack to compile an empty user program with the basis, so the client resource requirements are not onerous; low effort optimizations can probably cut the binary size in half.
An open question is how to manage binaries. Achieving the goals above requires an archive of binaries available as easily as CakeML version control; this should not be in the main repository since every update would add ~2.5 MB to the repository download size (currently 94 MB). A side repository would be a viable option (especially if it is updated less frequently than every CI build), or a large file storage system could be implemented (but this makes it more likely to not exist when a user needs it).
