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0 pointsmunificent2y ago0 comments

I'm not aware of any technical reasons why a given language would profoundly struggle to have a good REPL. I think it's mostly a matter of culture where REPLs aren't a priority in some language ecosystems because programmers there don't generally work that way.

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jerf2y ago

I'm not immediately aware of one either which is why I asked. HM does have its advantages but static languages are generally pretty clear on the type of an expression without annotations and just giving a variable the type of what it is set to achieves most of what you're looking for. It just occurred to me I couldn't name an instance of a static language without HM that does that, though. (At least I'm assuming LISP REPLs generally operate dynamically.)

munificentOP2y ago

One thing that does make it kind of weird is that a lot of statically typed languages that aren't from the ML family have a grammar top level that isn't imperative. In C#, Java, Dart, etc. The top level of a source file is purely declarative.

That can make a REPL sort of semantically weird. Do you allow variable declarations? If so, are they local or global? Do you allow class declarations in them? If so, can they access previous declarations?

All of that's easier in a dynamically typed language where the top level of a program is more or less just regular imperative code.

It's not insurmountable though, because you can be a little hand-wavey about semantics in a REPL if needed.

j / k navigate · click thread line to collapse

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jerf2y ago

munificentOP2y ago

All of that's easier in a dynamically typed language where the top level of a program is more or less just regular imperative code.

It's not insurmountable though, because you can be a little hand-wavey about semantics in a REPL if needed.

j / k navigate · click thread line to collapse