This is fine in practice as unexpected runtime errors are rare in Gleam. I’ve yet to have any in any and I’ve been using it in production for years.

It would be great if the BEAM had a source map like system so it can have the same high quality runtime errors and debugger support that JS has, but I think that’s unlikely to ever happen.

A REPL would be nice, but there hasn’t been enough demand to motivate any work so far. Language server features are overwhelming the majority of demand when it comes to tooling.