4 ms·

The difference between curried langs like OCaml and Haskell and languages like Ruby and Elixir are that the leaving out of parens actually means something, ie.

by bjz_ 10y ago

The difference between curried langs like OCaml and Haskell and languages like Ruby and Elixir are that the leaving out of parens actually means something, ie. all functions take one argument. If you wanted parens whilst maintaining the same semantics, you would end up having to do write: `add(2)(3)`

stuartaxelowen 10y ago
Indeed, but leaving out the parens makes more work for humans. What does `a b c` mean? `a(b)(c)`? `a(b(c))`? If the only thing that is gained by leaving out the parens is brevity, I don't think its worth it.
- reycharles 10y ago
  It would be `(a(b))(c)`. Interestingly, you're already leaving out parens for brevity.
- deno 10y ago
  But it’s not `a b c`. Rather it’s something like `verb noun noun`. Which is much less ambiguous. In a language with currying semantics [(((a(b))(c))(d)] the only logical explicit syntax sugar would be LISP-like, so (v n n), (v (v2 n)). That’s imo way worse — you end up with lots of useless junk)))))))) in anything non-trivial.
  - stuartaxelowen 10y ago
    What about `verb noun verb noun`? Is the second verb a parameter or is it being invoked on the noun?
    - thedufer 10y ago
      It's a parameter. The rule isn't complicated - functions are left-associative. That's all you have to remember.
- evincarofautumn 10y ago
  It’s no different than having to know the associativity of an operator. Does “a - b - c” mean “(a - b) - c” or “a - (b - c)”? The former, for no reason other than a long history of convention. Same goes for function application. And you could make the same argument about languages that require parentheses for function calls: what does “a(b)(c)” mean? “(a(b))(c)” or “a((b)(c))”? What’s gained is that the syntax mirrors the semantics. If you have a function “f : int -> bool -> int”, then “f 5” has type “bool -> int” and “f 5 true” has type “int”. It’s not like in Forth where you can’t tell from the syntax how many arguments a function takes. That said, I do think right-associative function application may be more intuitive—I like having it in Perl, for example.
  - eru 10y ago
    You get right-associative function application (in Haskell) by putting $ in between your functions. (And if you are using composition instead, it associates in both directions.)
- rixed 10y ago
  More work for humans used to something else. At this point it's worth reminding that ML syntax was originally designed to make programs more palatable to maths students...

by bjz_ 10y ago

stuartaxelowen 10y ago

Indeed, but leaving out the parens makes more work for humans. What does `a b c` mean? `a(b)(c)`? `a(b(c))`? If the only thing that is gained by leaving out the parens is brevity, I don't think its worth it.

reycharles 10y ago
It would be `(a(b))(c)`. Interestingly, you're already leaving out parens for brevity.
deno 10y ago
But it’s not `a b c`. Rather it’s something like `verb noun noun`. Which is much less ambiguous. In a language with currying semantics [(((a(b))(c))(d)] the only logical explicit syntax sugar would be LISP-like, so (v n n), (v (v2 n)). That’s imo way worse — you end up with lots of useless junk)))))))) in anything non-trivial.
- stuartaxelowen 10y ago
  What about `verb noun verb noun`? Is the second verb a parameter or is it being invoked on the noun?
  - thedufer 10y ago
    It's a parameter. The rule isn't complicated - functions are left-associative. That's all you have to remember.
evincarofautumn 10y ago
It’s no different than having to know the associativity of an operator. Does “a - b - c” mean “(a - b) - c” or “a - (b - c)”? The former, for no reason other than a long history of convention. Same goes for function application. And you could make the same argument about languages that require parentheses for function calls: what does “a(b)(c)” mean? “(a(b))(c)” or “a((b)(c))”? What’s gained is that the syntax mirrors the semantics. If you have a function “f : int -> bool -> int”, then “f 5” has type “bool -> int” and “f 5 true” has type “int”. It’s not like in Forth where you can’t tell from the syntax how many arguments a function takes. That said, I do think right-associative function application may be more intuitive—I like having it in Perl, for example.
- eru 10y ago
  You get right-associative function application (in Haskell) by putting $ in between your functions. (And if you are using composition instead, it associates in both directions.)
rixed 10y ago
More work for humans used to something else. At this point it's worth reminding that ML syntax was originally designed to make programs more palatable to maths students...