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Could anyone summarize how well PureScript and Elm treat sourcemaps/debugging in the browser? For a while I thought that js_of_ocaml didn't support sourcemaps,

Could anyone summarize how well PureScript and Elm treat sourcemaps/debugging in the browser? For a while I thought that js_of_ocaml didn't support sourcemaps, but it turns out, one of my dependencies wasn't compiled with debug flag (-g) and I was able to get a pretty good sourcemaps/debugging experience in Chrome dev tools once I fixed that issue. Is there something js_of_ocaml can learn from PureScript/Elm's JS compilation toolchain? Or should we look to CLJS (which I'm also really excited about) as the best example?

purescript 12y ago
I can't really comment on source maps in Elm, but the approach in PureScript has been to generate clean, readable JS which is debuggable directly. Source maps are on the roadmap, but not really a priority right now. I haven't heard any complaints about the ability to debug compiled PureScript yet.
- jordwalke 12y ago
  That's a nice approach for debugging! If the mapping is close enough, I don't mind reading the JS output. I'm curious about the general approach to compilation, though. It seems like a statically typed language could take advantage of the knowledge of types to generate an even more efficient version of the program that uses typed arrays and views (though, yes, it would require implementing a garbage collector unless relying on some kind of WeakMap in the JS engine). I've heard of garbage collected languages compiling to LLVM which would allow Emscripten to assist you, but I've also heard that LLVM has a really hard time with GC languages.
  - purescript 12y ago
    Right now, the translation is very direct. My basic rule of thumb is - only perform those optimizations which the user opts into. Some things are standard though, like a few inlining rules and tail call elimination, but the plan is to provide a rewrite rules engine so that the developer can be as fine-grained as they like when it comes to optimizations.

purescript 12y ago

I can't really comment on source maps in Elm, but the approach in PureScript has been to generate clean, readable JS which is debuggable directly. Source maps are on the roadmap, but not really a priority right now. I haven't heard any complaints about the ability to debug compiled PureScript yet.

jordwalke 12y ago
That's a nice approach for debugging! If the mapping is close enough, I don't mind reading the JS output. I'm curious about the general approach to compilation, though. It seems like a statically typed language could take advantage of the knowledge of types to generate an even more efficient version of the program that uses typed arrays and views (though, yes, it would require implementing a garbage collector unless relying on some kind of WeakMap in the JS engine). I've heard of garbage collected languages compiling to LLVM which would allow Emscripten to assist you, but I've also heard that LLVM has a really hard time with GC languages.
- purescript 12y ago
  Right now, the translation is very direct. My basic rule of thumb is - only perform those optimizations which the user opts into. Some things are standard though, like a few inlining rules and tail call elimination, but the plan is to provide a rewrite rules engine so that the developer can be as fine-grained as they like when it comes to optimizations.