Add (lambda_expression) without bindings to locals.scm.

[rwjblue]

When you have a lambda expression like:

val fruits = List("apple", "banana", "avocado", "papaya")

val countsToFruits = fruits.groupBy(fruit => fruit.count(_ == 'a'))

for ((count, fruits) <- countsToFruits) {
  println(s"with (fruits) 'a' × $count = $fruits")
}

The fruit => fruit.count(_ == 'a') lambda expression (note: without wrapping parenthesis) does not create a (binding) node. Its syntax tree is:

    (lambda_expression) ; [5:18 - 47]
     parameters: (identifier) ; [5:18 - 22]
     (call_expression) ; [5:27 - 47]
      function: (field_expression) ; [5:27 - 37]
       value: (identifier) ; [5:27 - 31]
       field: (identifier) ; [5:33 - 37]
      arguments: (arguments) ; [5:38 - 47]
       (infix_expression) ; [5:39 - 46]
        left: (wildcard) ; [5:39 - 39]
        operator: (operator_identifier) ; [5:41 - 42]
        right: (character_literal) ; [5:44 - 46]

That example just happens to be exactly one of the example from https://www.scala-lang.org/ (see playground) 😁.

[ckipp01]

Thanks for this @rwjblue! If I'm not mistaken can you try to add this to some of the hightlight query tests which should verify that this indeed is capturing the way we'd want.