The whole magic about CL's condition system is to keep on executing code in the context of a given condition instead of immediately unwinding the stack, and this can be done if you control code generation.
Everything else necessary, including dynamic variables, can be implemented on top of a sane enough language with dynamic memory management - see https://github.com/phoe/cafe-latte for a whole condition system implemented in Java. You could probably reimplement a lot of this in WASM, which now has a unwind-to-this-location primitive.
Scheme doesn't have restarts as a core concept like Common Lisp, but it does have continuations. For the Scheme implementation I worked on [0], the exception system is built on top of the continuation system. In other words, Scheme exceptions are not Wasm exceptions. However, we did find a use for Wasm exceptions in the implementation of the runtime. We realized it would be useful to mark the entry point into Scheme with a Wasm 'try' block for re-entrancy reasons. Programs might call from Scheme to JS back to Scheme and on and on. When we suspend the current continuation we throw a Wasm exception and find the correct entry point for doing our stack tomfoolery, re-throwing until we find it. I don't know if my explanation makes any sense but that's how we're using Wasm exceptions.
The whole magic about CL's condition system is to keep on executing code in the context of a given condition instead of immediately unwinding the stack, and this can be done if you control code generation.
Everything else necessary, including dynamic variables, can be implemented on top of a sane enough language with dynamic memory management - see https://github.com/phoe/cafe-latte for a whole condition system implemented in Java. You could probably reimplement a lot of this in WASM, which now has a unwind-to-this-location primitive.
Also see https://raw.githubusercontent.com/phoe-trash/meetings/master... for an earlier presentation of mine on the topic. "We need means of unwinding and «finally» blocks" is the key here.