• janAkali@lemmy.one
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    10 months ago

    Yes the compiler/interpreter can figure it out on the fly, that’s what we mean by untyped languages.

    Are there untyped languages? You probably meant ‘dynamically typed languages’.

    But even statically typed languages can figure out most types for you from the context - it’s called ‘type inference’.

    • nul@programming.dev
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      10 months ago

      Most of my code is untyped. First I type it, then I realize it’s all wrong and use backspace to untype it.

    • Traister101@lemmy.today
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      10 months ago

      Assembly probably? So low level you kinda just play with bits. That’s all I can think of for an untyped language. Everything else I’m aware of is dynamically or statically typed

      • Chobbes@lemmy.world
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        10 months ago

        I kind of feel like “untyped” is a term that doesn’t really have a proper definition right now. As far as I can tell when people say “untyped” they usually mean it as a synonym for whatever they consider “dynamically typed” to mean (which also seems to vary a bit from person to person, haha). Sometimes people say assembly is untyped exactly for this reason, but you could also consider it to have one type “bits” and all of the operations just do things on bits (although, arguably different sized registers have different types). Similarly, people sometimes consider “dynamically typed languages” to just be “unityped” (maybe monotyped is more easily distinguished from untyped, haha) languages at their core, and if you squint you can just think of the dynamic type checks as a kind of pattern matching on a giant sum type.

        In some sense values always have types because you could always classify them into types externally, and you could even consider a value to be a member of multiple types (often programming languages with type systems don’t allow this and force unique types for every value). Because you could always classify values under a type it feels kind of weird to refer to languages as being “untyped”, but it’s also kind of weird to refer to a language as “typed” when there isn’t really any meaningful typing information and there’s no type system checking the “types” of values. Types sort of always exist, but also sort of only exist when you actually make the distinctions and have something that you call a “type system”… In some sense the distinction between static and dynamic typing is sort of an arbitrary implementation detail too (though, of course, it has impacts on the experience of programming, and the language design makes a bit of a difference in terms of what’s decidable :) (and obviously the type system can determine what programs you consider to be “valid”)… But you can absolutely have a mix of static type checking and dynamic typing, for instance… It’s all a little more wishy washy than people tend to think in my opinion).

        • Traister101@lemmy.today
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          10 months ago

          Well like asembly has “int types” and “float types” as there’s specific instructions for those operations but those instructions don’t actually care if the bits are for a float or an int. Types in a language are used to restrict the valid operations. In a statically typed language you cannot call cat.bark() or dog.meow() because the property’s of the type, what things you can do with it are known before the program runs. In a dynamically typed language such as Python cat.bark() might or might not be valid so it has to check at runtime for a method throwing an error if it doesn’t exist.

          Static/Dynamic typing is a difference of when. Java has static typing but you can also just pass raw Objects around and cast when needed. It even throws a runtime exception similar to how Python or JavaScript would fail. However Java is of course ultimately statically typed everything just shares a common parent class and has types at runtime which allows for some some psudo dynamic behavior

          • Chobbes@lemmy.world
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            10 months ago

            There’s operations that treat bits like floats and operations that treat them like various kinds of ints, but the meaning of bits is in the eye of the beholder. There’s even good examples of mixing and matching integer and floating point operations to clever effect, like with the infamous fast inverse square root. I feel like people often think mathematical objects mean something beyond what they are, when often math is kind of just math and it is what it is (if that makes sense… it’s kind of like anthropomorphizing mathematical objects and viewing them through a specific lens, as opposed to just seeing them as the set of axioms that they are). That’s kind of how I feel with this stuff. You can treat the bits however you want and it’s not like integer operations and bitwise operations have no meaning on supposedly floating point values, they do something (and mixing these different types of operations can even do useful things!), it just might not be the normal arithmetic operations you expect when you interpret the number as a float (and enjoy your accidental NaNs or whatever :P).

            The difference of static and dynamic typing being when you perform the type checking is partially why I consider it to be a somewhat arbitrary distinction for a language (obviously decidable static type checking is limited, though), and projects like typescript have shown that you can successfully bolt on a static type system onto a dynamic language to provide type checking on specific parts of a program just fine. But obviously this changes what you consider to be a valid program at compile time, though maybe not what you consider to be a valid program overall if you consider programs with dynamic type errors to be invalid too (which there’s certainly precedence for… C programs are arguably only real C programs when they’re well-defined, but detecting UB is undecidable).

    • AVincentInSpace@pawb.social
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      10 months ago

      I guess “untyped” could mean “weakly typed”, like how shell and DOS batch are, where everything is a string until you say “hey I want to do math on this” at which point the interpreter turns it into a number, does math on the number, and then turns it back into a string before saving it back to the variable

    • Thorry84@feddit.nl
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      10 months ago

      Well that would depend on the definition and what you exactly mean by untyped.

      The untyped part is usually referring to the way the programmer interacts with the language, for example not setting a type for variables and parameters. But then there is the question of is the programmer ever allowed to explicitly set the type. And further more, if the programmer explicitly set the type, does this mean the type can’t change at a later point? And another question could be, can the programmer check or enforce what type a variable or parameter is? And the question, if there is only one type of data in the language, would that be a typed or untyped language? But I would consider these to be details and all fall under the untyped umbrella, with untyped just meaning not-typed.

      Then there’s the question of the technical implementation of the language. Defining a language is one thing, actually having it run on a real system is another. Usually technical systems at some point require explicit types. Something somewhere needs instructions on how to handle the data and this usually leads to some kind of typing instructions being added along with the data. But depending on how many abstraction layers there are, this can soon become a very pedantic discussion. I feel what matters is the design, definition and intend of a language. The actual technical implementation isn’t what matters in my opinion.

      I feel like there are so many programming languages and technical systems at this point, every variation and exception exists. And if you can think of one that doesn’t exist, expect a follow up comment of somebody pointing out it does exist after all, or them having started a project to make it exist in the near future.

      • Poutinetown@lemmy.ca
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        10 months ago

        Would you say OCaml or any ml family language would be untyped since they have type inference?

        • Thorry84@feddit.nl
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          10 months ago

          From what I know about those I would consider those to be typed languages. Even if the programmer doesn’t explicitly assign the types, he needs to be aware of them and take into account what type something will be. I am familiar with F# and it’s strongly typed for example.