Stream: ideas

Topic: running tasks in the repl

Richard Feldman (May 25 2024 at 11:59):

some of us talked about this idea at Software You Can Love in Milan: we could allow running tasks in roc repl

Richard Feldman (May 25 2024 at 12:00):

for example, you could write at the prompt:

» File.writeUtf8! path contents

...and it would do that

Richard Feldman (May 25 2024 at 12:00):

the rule would be that you'd have to actually use the ! suffix to indicate that you really want to run the effect

Richard Feldman (May 25 2024 at 12:01):

and we'd infer the platform based on the main.roc application (or platform) in the current dir where you launched the repl

Richard Feldman (May 25 2024 at 12:01):

(configurable via cli arg)

Brendan Hansknecht (May 25 2024 at 13:19):

Intriguing. How would we ensure effects only run once and deal with linking? I think the current repl just builds up one long file and runs everything

Agus Zubiaga (May 25 2024 at 13:22):

Yeah, I was thinking about that on the plane. We would somehow have to replace the def’s expression with the result, but I don’t think we can really do that. It could include pointers that won’t work on the next run.

Norbert Hajagos (May 25 2024 at 15:34):

The idea is really good and I like it. Would packages defined in main be allowed just like how the platform is infered?

Agus Zubiaga (May 25 2024 at 19:16):

Yeah, we should do that separately. That doesn’t require any major changes to the repl.

Last updated: Jun 16 2026 at 16:19 UTC