Make "fewerBraces" available outside snapshot releases

[liufengyun]

@odersky

Does it mean that I have to use braces for curried blocks and blocks as operands? Not necessarily. We can use indentation by adding explicit function names. In the first case:

    xs.groupMap:
      x => x * x
    .apply:
      x => x.toString

That works today. It’s currently not as efficient as two inline arguments since it performs an eta expansion of the part before the .apply. But we can fix this in the compiler with a peephole optimization.

I am not sure if someone has proposed with before:

   xs.map with x => x + 1
     .foldLeft(4) with (x, y) => x + y

    xs.groupMap 
      with group = x => foo(x)
      with map = x => x.toString

    obj.foo 
      with a = bla, b = bla
      using cap1, cap2

If it is possible to write e with e1, e2, ... to mean e(e1, e2, ...), it seems to have the potential to (1) reduce the usage of parenthesis, (2) deal with long arguments(such as lambdas) and (3) works very well with named arguments.

However, I’m not sure it makes sense technically — disambiguation seems to be complicated.