Use REPL for snips of stuff. But I can’t see the point of trying to run code that is known to be broken. But yes use REPL for the bit you think is right.
Or are you saying you need to put a break point in just before the broken bit so you can work out something?
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Yeah, the elaborator would generate something like a 'ReportedIssue' node when a problem is encountered. This crashes the program if it is run, which would allow you to still experiment with the program while it's in a partially correct state.
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GHC has something similar with `-fdefer-type-error`, for example.
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So for Haskell you’ve got the mechanism, if I understand correctly. For dynamic languages like JavaScript or Python you can just try it out, much like a BASH script.
So which languages would you suggest should have this capability?
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I'm suggesting for statically typed languages like Rust, OCaml, SML, Scala, Java, Idris, Lean, etc. Languages where types are required as a part of understanding the meaning of a program. Put another way, languages that are intrinsically typed (as opposed to extrinsically typed).
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Hmm I can see why said this added complexity.
It would probably trigger a chain of unresolved types/calls results.
This might mean that in many circumstances it still would not be possible to execute.
You might have to introduce an ‘unresolved type’ as a holder.
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What do you mean by ‘a holder’? I'm also not sure what you mean be a chain of unresolved types? Do you mean during type checking?
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Well let’s say that we had an error where a call you made did not return the type you stated it would. Ie a compiler error. But we put this to one side. The type you declared clearly does not exist. We’d have to put a place holder in there to ‘shore up’ the code.
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We’d then need to simulate all the other method calls you make on that non existent type.
So the compiler would now need to generate stubs for the calls and provide an implementation that threw an exception (for example).
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Ahh interesting! Yeah I'm not sure the right approach would be for a language like #EK9. I'm more used to implementing dependently typed languages tbh!
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Rust might be a better place to look – it already does error recovery with error sentinels, it just doesn't do the final step of emitting further code after errors are encountered.