Sky Rose (May 05 2023 at 05:05): Sky Rose (May 05 2023 at 05:05):I've been wondering: Is it possible to write a platform in roc, providing a subset of the features of the parent platform?
I see a couple use cases:
Sandboxing. Suppose you have a full featured platform, and want to provide a way to write apps that use a safe subset, enforced with the strength of roc platforms.
- Example a. A university programming class is taught in roc. The students submit homework as roc apps. They could do it on some official cli-app platform, but the grader instead has the students submit their work as apps on a custom cli-sandbox platform so she can run their submissions safely.
- Example b. A game includes a powerful modding system as a roc platform. They also publish a nested platform for cosmetic-only mods that the child platform guarantees don't affect gameplay, so they can be safely allowed in competitive game modes.
Better interfaces / frameworks. Example: Some roc-browser platform exists that is a thin layer on top of browser APIs. Someone makes a child platform based on it that gives an easy-to-use API for a Single Page App framework, like The Elm Architecture, so app developers can use that instead of making raw browser API calls. Though maybe this could be done with a library instead of a platform.
One hurdle I see is memory management. You need to be able to allocate memory in order to write a platform, but roc programs have automatic memory management. Could the alloc implementation written in roc just create a big array?
Brendan Hansknecht (May 05 2023 at 05:15):Interesting idea. I would assume that if we enabled this, you probably wouldn't be able to affect roc_* functions (used for memory management among other things). Those would stay as the ones specified by the original platform. Instead, you would import the platform just like a regular roc app, but instead of defining an app, you would be re-exporting it with a new API.
This definitely could be possible. Would essentially just require packages that can depend on and re-export platforms. Would need to add extra constraints such that it could require a function much like platforms currently do.
I'm not exactly sure the ergonomics/tradeoffs of doing this in roc vs telling people to just modify the rust CLI platform, but this does sound like a nice use case.
Brendan Hansknecht (May 05 2023 at 05:16):Aside: maybe we should move this to #ideas
Sky Rose (May 06 2023 at 15:11):I don't have permission to move topics, so if it belongs in #ideas, someone with permission will have to move it.
Notification Bot (May 06 2023 at 15:24):This topic was moved here from #beginners > nested platforms? by Anton.
Last updated: Jun 16 2026 at 16:19 UTC