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(as an interested university student:) From Programming at a small scale in Javascript and Logo¹, I have gathered that not knowing what type something is can be annoying. They also have REPLs, which is pretty nice. From various blog posts and debugging Rust programs, I have learned that not having a REPL can be annoying. Are there languages that have both?

(¹ Logo is a "lisp" with omitable parentheses, where these also don't define runtime-mutable s-expressions, lists are in brackets, and also Logo doesn't have structs, giving it bad maintainability outside of not having Type Annotation too)

Candidates

  • C# : Does it have a repl?
  • Java in BlueJ somehow
  • sometimes people just put Lisp or Lua in their C/Rust++ program (emacs, shenzhen I/O(game)), this accomplishes a similar task of making some debugging or scripting code faster to compile/interpret, but slower to run
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[-] Octorine@midwest.social 8 points 1 month ago

Haskell is typed and has a repl.

[-] Ephera@lemmy.ml 6 points 1 month ago

I guess, Python technically counts, although the type annotations were one hell of an afterthought.

I do feel like the two features are somewhat at odds with each other.
A REPL is useful for quickly trying something out, which you'd typically use to put together a quick script. In a larger application, you generally want to define unit tests, which make your "quickly trying something out" reproducible and automateable.
Meanwhile, type annotations primarily start to shine in larger applications, where you cannot keep the whole context in your head and where refactorings become problematic, when nothing checks that the parts still work together.

In some sense, they also don't work well together. Type annotations work best when the whole context is known. But in a REPL, you almost always have an incomplete context, because you're still typing everything out.
So, it cannot type-check the first few lines you write and it becomes awkward to try to show type errors once the context is complete, because the code isn't on-screen anymore.

[-] CameronDev@programming.dev 2 points 1 month ago
[-] leftzero@lemmy.dbzer0.com 1 points 1 month ago

C# : Does it have a repl?

As a procedural language (though it's becoming more and more functional-like with each release) C# isn't exactly designed to work with a REPL, but I think Visual Studio (the IDE, not the text editor) comes with an immediate window that works as one, and a quick internet search finds many third party ones, like .NET fiddle for the web, or CSharpRepl for the command line.

[-] JackbyDev@programming.dev 1 points 1 month ago
this post was submitted on 26 Oct 2025
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Programming Languages

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