Allow any name in single parameter lambda functions

Language Design
11

I have an idea of how to get the advantages from a similar syntax without the mentioned disadvantages.

  • You can:
    • Make to use $ before the lambda scope (before {)
    • Make to start the name of the parameter with $
  • Why this helps:
    • I can not accidentally mix up common captured variables and implicit parameters (now it is insensitive to them)
    • I can guess from such implicit parameter what it is (not like it that can correspond to anything in the world)
    • Syntax is still laconic
    • It is also insensitive to nested lambdas parameter names:
      • Lambda, marked as $ must use one (not 0 or 2+) new implicit parameters.
      • So, when you would try to rename 2 parameters such way that they have the same name, You would have compilation error.
      • Actually, that is not real insensitivity, but there is no implicit converting from (X) -> T to () -> T or something like that.
      • The attitude when there are collisions is similar to one when the explicit syntax is used, but here we get an error, but not just warning.
  • Of course, using any of the approaches of implicit parameter name is bad when you have a big lambda.
  • The comparison of syntaxes:
    • Explicit
      { cat -> feed(cat) }
    • it
      { feed(it) }
    • My idea
      ${ feed($cat) }
  • The syntax may be simplified more I think

So what do you think of it?