Re: Lightweight function syntax (again)

[Tony Finch <dot@...>]

I've been playing around with a Haskell-ish syntax.

  function ::= function `(´ [parlist] `)´ <block> end
             | `\´ [parlist] `->´ <exp>
             | `\´ [parlist] do <block> end

This isn't entirely great. I think it works better if there is a right
delimiter on the body of the lambda. For example:

  each = \ f -> \ t do
      for k,v in pairs(t) do
        f(k,v)
      end
    end

  r = {}

  each \ k,v do r[k] = v+1 end {1,2,3} --> r = {2,3,4}

  each \ k,v -> print(k,v) (r) -- fail

  each(\ k,v -> print(k,v)) (r) -- ok

(I'm not saying that this each() function is a great idea, mind you!)

So I'm leaning towards a syntax like

  function ::= function `(´ [parlist] `)´ <block> end
             | `\´ [parlist] `(´ [explist] `)´
             | `\´ [parlist] <funbody>

  funbody  ::= <function> | <dostat> | <ifstat> | <loopstat>

which would allow

  each = \ f \ t for k,v in pairs(t) do
                   f(k,v)
                 end
  r = {}

  each \ k,v do r[k] = v+1 end {1,2,3}

  each \ k,v (print(k,v)) (r) -- win

  each \...(print(...)) (r) -- heh

Tony.
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