24 ms·

> To me, all you're doing here is describing an object-based language in which functions are first-class. Obviously, Urbit didn't invent this concept. Its prede

by pcmonk 9y ago

> To me, all you're doing here is describing an object-based language in which functions are first-class. Obviously, Urbit didn't invent this concept. Its predecessors used normal names for these terms. Why does Urbit invent new ones? That's a pretty (unintentionally) misleading description of it. What is an object? An Urbit function has basically nothing that an OOP object has. No class, no inheritance, no attributes, and no methods. It's just a way of encapsulating a formula (VM assembly expression) in a way that's convenient to call with formulas. It uses the the "core" pattern because it's convenient. "Arm" is a pretty specific term that refers to the way an "element" of a core is represented in the core. When you want to map a particular use of cores to its underlying representation in the "core" pattern, you want to be able to talk about specific data structures. In general, Urbit errs on the sides of giving names to concepts that could only otherwise be described in multiple sentences. Most projects just don't give names to those concepts. Urbit needs better human descriptions of its concepts, but using traditional names for them would be misleading.

tptacek 9y ago
How are these not problems that every VM for a high-level programming language also addresses?
- pcmonk 9y ago
  They absolutely do, with their own terms. Isn't an S-expression just a list? Isn't a method just a "member function", which is really just a function, which is really just a subroutine? Every language comes up with its own terms, especially for things that are a little different from previous work. Urbit isn't trying to solve many new problems; it's trying to solve old problems in different ways. They just want to be able to talk about the constructs in their solutions.
  - tptacek 9y ago
    Right, I get that. So I guess my question is: in what ways justifying new terminology are the approaches taken by Urbit different? And whether or not they're different enough from prior art to merit obscure new terms, are those differences worthwhile, or are they different for the sake of being different? Because not all of the last 30 odd years of systems and programming research was pointless.
    - pcmonk 9y ago
      > not all of the last 30 odd years of systems and programming research was pointless. Indeed, which is why it's a shame our primary server OSes (Unix-likes) can't incorporate them. Urbit can. As for what are the approaches different, there have been many words spilled over that, but here's a few examples to wit, most of which exist in one or two other systems, but aren't widely used: - All events are transactions, down to the VM level. There's no concept of an event that left garbage around because power was cut or the machine was rebooted. You can always crash an event, making it as if it never happened. - Single-level store. Never worry about ORM because your in-memory state never goes away (because all events are transactions). - Persistent connections with exactly-once messaging. Disconnection is just seen as long latency. - Strict, purely functional language with a strong type system but no Hindley-Milner (so you don't need category theory). - Sane indentation for a functional language, known as "backstep". - The file system is a typed revision control system, which allows intelligent diffs on types other than plain text. Most, if not all, of these, have been described in research, but nobody's bothered to build a system with them.
      - Munksgaard 9y ago
        I'm curious: What's the advantage of ditching Hindley-Milner?
        Chattered 9y ago
        I want to give urbit a try. I have a planet, but last time I fired it up the latency was so bad that I wasn't having fun. I'll try again sometime. I can even get behind runes, and I set up abbreviations in Emacs to learn their names. And generally, I like the philosophy of language where short, one syllable, old/middle English words are used in place of the less familiar Latin/Greek derived words. I don't have a problem with revising our existing vocabulary in this way. But the attitude to type theory strikes me as anti intellectual, precisely because we get nonsense claims about Hindley Milner requiring category theory. This sort of misinformation does no good for anyone.
        vmchale 9y ago

by pcmonk 9y ago

tptacek 9y ago

How are these not problems that every VM for a high-level programming language also addresses?

pcmonk 9y ago
They absolutely do, with their own terms. Isn't an S-expression just a list? Isn't a method just a "member function", which is really just a function, which is really just a subroutine? Every language comes up with its own terms, especially for things that are a little different from previous work. Urbit isn't trying to solve many new problems; it's trying to solve old problems in different ways. They just want to be able to talk about the constructs in their solutions.
- tptacek 9y ago
  Right, I get that. So I guess my question is: in what ways justifying new terminology are the approaches taken by Urbit different? And whether or not they're different enough from prior art to merit obscure new terms, are those differences worthwhile, or are they different for the sake of being different? Because not all of the last 30 odd years of systems and programming research was pointless.
  - pcmonk 9y ago
    > not all of the last 30 odd years of systems and programming research was pointless. Indeed, which is why it's a shame our primary server OSes (Unix-likes) can't incorporate them. Urbit can. As for what are the approaches different, there have been many words spilled over that, but here's a few examples to wit, most of which exist in one or two other systems, but aren't widely used: - All events are transactions, down to the VM level. There's no concept of an event that left garbage around because power was cut or the machine was rebooted. You can always crash an event, making it as if it never happened. - Single-level store. Never worry about ORM because your in-memory state never goes away (because all events are transactions). - Persistent connections with exactly-once messaging. Disconnection is just seen as long latency. - Strict, purely functional language with a strong type system but no Hindley-Milner (so you don't need category theory). - Sane indentation for a functional language, known as "backstep". - The file system is a typed revision control system, which allows intelligent diffs on types other than plain text. Most, if not all, of these, have been described in research, but nobody's bothered to build a system with them.
    - Munksgaard 9y ago
      I'm curious: What's the advantage of ditching Hindley-Milner?
      - Chattered 9y ago
        I want to give urbit a try. I have a planet, but last time I fired it up the latency was so bad that I wasn't having fun. I'll try again sometime. I can even get behind runes, and I set up abbreviations in Emacs to learn their names. And generally, I like the philosophy of language where short, one syllable, old/middle English words are used in place of the less familiar Latin/Greek derived words. I don't have a problem with revising our existing vocabulary in this way. But the attitude to type theory strikes me as anti intellectual, precisely because we get nonsense claims about Hindley Milner requiring category theory. This sort of misinformation does no good for anyone.
      - vmchale 9y ago