Stream: ideas

Topic: `roc glue` UX ideas

Richard Feldman (Jul 16 2023 at 11:13):

so based on my experience using roc glue at work, I have some ideas for things I think would be UX improvements, which I'd love to talk through!

Richard Feldman (Jul 16 2023 at 11:18):

in general, I think the glue experience I'd like to get to would involve:

• if I tell roc glue to generate glue for an app module rather than a platform module, instead of erroring, it looks up the platform that app uses, and proceeds to generate glue for that platform as normal
• being able to specify the glue spec as a URL (just like we do with packages) so I don't have to obtain e.g. RustGlue.roc via source control
• generating glue for hosted modules automatically (this was always planned and I currently have a WIP PR for it)

Richard Feldman (Jul 16 2023 at 11:19):

those all feel pretty uncontroversial to me, but I have some other ideas that seem to have more pros and cons

Richard Feldman (Jul 16 2023 at 11:27):

for example:

• I'm coming to the conclusion that the best way to use glue is to run it on every build of the platform (e.g. ideally someday in build.rs or build.zig) and then .gitignore all the files it generates
• In that world, I think we want roc glue to regenerate the given directory from scratch every time (e.g. generate into a tempdir and then rename the tempdir over the target dir if everything wrote successfully) so that you don't end up with potential situations where some people on the team have stale stuff left over from previous builds, and a build tool happens to pick up on those and do different things with them, which would lead to non-reproducibility and potentially nasty bugs to track down. I think if we make this change now, everyone will make sure their builds work with it, but it would be a difficult breaking change to make in the future!
• if we're letting you download from a URL, I think I'd personally like roc glue's argument order and defaults to change - specifically, have glue spec first (likely a URL), then output dir (defaulting to "glue/") and finally target roc file (still defaulting to "main.roc") - so this way if I just say roc glue and then the URL, it will generate it from main.roc into a directory named glue/.
• Since it's writing into that directory, I could see an argument for not having a default argument there (like, you have to explicitly say roc glue glue/ ...) but it's hard for me to imagine someone having a directory that randomly happens to be named "glue", of all things, and getting burned by this.

Richard Feldman (Jul 16 2023 at 11:31):

building on that point:

• I think in the future it would be good for roc glue to incorporate on-disk caching - so that if you run it and your platform's roc code has not changed, it doesn't even bother regenerating anything
• in that world, it feels like it makes even more sense to regenerate the dir from scratch every time instead of adding files to it like it does today

Richard Feldman (Jul 16 2023 at 11:31):

any thoughts on all of that welcome!

Luke Boswell (Jul 16 2023 at 13:19):

This all sounds reasonable to me. :+1:

Last updated: Jun 16 2026 at 16:19 UTC