Hacker News Reader

Comment by Skinney | Hacker News Reader

Yes. Stabel is staticly typed, and types are inferred if the type signature is left out. You could also write the code as:

    def: cube
    type: Int -- Int
    : dup dup * *

View on HN

I never thought about this much but now and it has been so since Forth anyway: why are definitions prefix? Why do they not gobble up the stack? I always found it easier to create everything uniform like [0]. And I did that for many years with asm and c as well because I thought it was faster than porting something (it probably was not but he).

I just like to minimize exceptions to rules and this seems a weird one to me. But probably has reasons I am unaware of (besides subjective readability which is, of course a very good reason).

[0] https://gist.github.com/tluyben/16ee2645c4c8aed813005d51488d...

Yes, in my own toy concatenative language, define is just a regular procedure. It takes two arguments off the stack. The first is a pointer to the name, the second is a pointer to a quotation with the definition body. It intentionally looks Forth-like but it's different under the hood:

    [ dup + ]      \ writes a lambda function to heap and push ptr
      : double ;   \ : writes the next symbol as a string to heap and push ptr
                   \ ; is define, writes definition into dict

The reason Forth did it the classic Forth way originally, I suspect, is because Forth's parser needs to be told to switch modes. Stop executing words directly and start compiling them. There isn't really anywhere to store a temporary string, so you need to tell it to start writing into the dictionary entry before you give it the string. In my language, using [ ] for quotations starts writing to the heap, which is also where strings go. This has the same practical effect.

I agree in principle about the benefits of everything being uniform. For Stabel, specifically, I need some way of seperating function-definition from function-implementation, and a prefix meta language seemed like the best bet. Didn't look at it too closely, though.

Thanks and, nice work with Stabel, we need more experiments in this space.

Does Stable support polymorphic functions? What kinds of data abstractions are possible? (I.e. something like records / structs / classes / Lua-like tables?)

Stabel has generics, but no protocols/interfaces/typeclasses _yet_.

Stabel allows you to define structs and unions, which gives you a lot of flexibility.

Great, now could you have a second copy of cube that did floating point?

Stabel doesn’t have floats, yet, but when it does: yes, if you put it in a different module.

So Stabel does not support (ad hoc) overloading, right? Will it support it?

Right.

Not sure. Ad-hoc polymorphism is currently in the design-phase and I'm looking at many possible solutions. But before I get to that point I still have a lot of stuff to implement first.

Reply on news.ycombinator.com