=====================================
no arguments
=====================================

fn() -> 1 end
fn () -> 1 end

---

(source
  (anonymous_function
    (stab_clause
      (arguments)
      (body
        (integer))))
  (anonymous_function
    (stab_clause
      (arguments)
      (body
        (integer)))))

=====================================
no arguments without parentheses
=====================================

fn -> 1 end

---

(source
  (anonymous_function
    (stab_clause
      (body
        (integer)))))

=====================================
one argument
=====================================

fn(x) -> x end

---

(source
  (anonymous_function
    (stab_clause
      (arguments
        (identifier))
      (body
        (identifier)))))

=====================================
one argument without parentheses
=====================================

fn x -> x end

---

(source
  (anonymous_function
    (stab_clause
      (arguments
        (identifier))
      (body
        (identifier)))))

=====================================
many arguments
=====================================

fn(x, y) -> x + y end

---

(source
  (anonymous_function
    (stab_clause
      (arguments
        (identifier)
        (identifier))
      (body
        (binary_operator
          (identifier)
          (identifier))))))

=====================================
many arguments without parentheses
=====================================

fn x, y -> x + y end

---

(source
  (anonymous_function
    (stab_clause
      (arguments
        (identifier)
        (identifier))
      (body
        (binary_operator
          (identifier)
          (identifier))))))

=====================================
multiline body
=====================================

fn x, y ->
  y
  x
end

---

(source
  (anonymous_function
    (stab_clause
      (arguments
        (identifier)
        (identifier))
      (body
        (identifier)
        (identifier)))))

=====================================
many clauses
=====================================

fn
  1 -> :yes
  2 -> :no
  other -> :maybe
end

---

(source
  (anonymous_function
    (stab_clause
      (arguments
        (integer))
      (body
        (atom
          (atom_literal))))
    (stab_clause
      (arguments
        (integer))
      (body
        (atom
          (atom_literal))))
    (stab_clause
      (arguments
        (identifier))
      (body
        (atom
          (atom_literal))))))

=====================================
with guard / no arguments
=====================================

fn
  () when node() == :nonode@nohost -> true
end

---

(source
  (anonymous_function
    (stab_clause
      (binary_operator
        (arguments)
        (binary_operator
          (call
            (identifier)
            (arguments))
          (atom
            (atom_literal))))
      (body
        (boolean)))))

=====================================
with guard / one argument
=====================================

fn
  x when x == [] -> x
end

---

(source
  (anonymous_function
    (stab_clause
      (binary_operator
        (arguments
          (identifier))
        (binary_operator
          (identifier)
          (list)))
      (body
        (identifier)))))

=====================================
with guard / multiple arguments
=====================================

fn
  x, y when x == [] -> x
end

---

(source
  (anonymous_function
    (stab_clause
      (binary_operator
        (arguments
          (identifier)
          (identifier))
        (binary_operator
          (identifier)
          (list)))
      (body
        (identifier)))))

=====================================
with guard / arguments in parentheses
=====================================

fn
  (x, y) when y == [] -> y
end

---

(source
  (anonymous_function
    (stab_clause
      (binary_operator
        (arguments
          (identifier)
          (identifier))
        (binary_operator
          (identifier)
          (list)))
      (body
        (identifier)))))

=====================================
with guard / multiple guards
=====================================

fn
  x when x > 10 when x < 5 -> x
end

---

(source
  (anonymous_function
    (stab_clause
      (binary_operator
        (arguments
          (identifier))
        (binary_operator
          (binary_operator
            (identifier)
            (integer))
          (binary_operator
            (identifier)
            (integer))))
      (body
        (identifier)))))

=====================================
pattern matching
=====================================

fn
  [h | tail] -> {h, tail}
  %{x: x} when x == 1 -> 1
end

---

(source
  (anonymous_function
    (stab_clause
      (arguments
        (list
          (binary_operator
            (identifier)
            (identifier))))
      (body
        (tuple
          (identifier)
          (identifier))))
    (stab_clause
      (binary_operator
        (arguments
          (map
            (map_content
              (keywords
                (pair
                  (keyword
                    (atom_literal))
                  (identifier))))))
        (binary_operator
          (identifier)
          (integer)))
      (body
        (integer)))))