================================================================================
Simple Structure Definition
================================================================================

struct { answer = 42 }

--------------------------------------------------------------------------------

(root
  (statement
    (expression
      (value
        (structure_definition
          (structure_instantiator
            (identifier)
            (statement
              (expression
                (value
                  (integer))))))))))

================================================================================
Structure Definition with Types
================================================================================

struct {
  answer <num> = 42
  stuff <[str]> = [ "some" "stuff" ]
}

--------------------------------------------------------------------------------

(root
  (statement
    (expression
      (value
        (structure_definition
          (structure_instantiator
            (identifier)
            (type_definition
              (type))
            (statement
              (expression
                (value
                  (integer))))
            (identifier)
            (type_definition
              (type
                (type)))
            (statement
              (expression
                (value
                  (list
                    (expression
                      (value
                        (string)))
                    (expression
                      (value
                        (string)))))))))))))

================================================================================
Nested Structure Definition
================================================================================

struct {
  bar <Bar>
  baz <Baz>
}

--------------------------------------------------------------------------------

(root
  (statement
    (expression
      (value
        (structure_definition
          (structure_instantiator
            (identifier)
            (type_definition
              (type
                (identifier)))
            (identifier)
            (type_definition
              (type
                (identifier)))))))))

================================================================================
Simple Structure
================================================================================

new Foo 

--------------------------------------------------------------------------------

(root
  (statement
    (expression
      (value
        (structure
          (identifier))))))

================================================================================
Complex Structure
================================================================================

User = struct {
  id <int> = random:integer()
  email <str>
  name <option(str)> = none
}

bob = new User {
  email = "bob@example.come"
}

--------------------------------------------------------------------------------

(root
  (statement
    (assignment
      (identifier)
      (assignment_operator)
      (statement
        (expression
          (value
            (structure_definition
              (structure_instantiator
                (identifier)
                (type_definition
                  (type))
                (statement
                  (expression
                    (function_call
                      (function_expression
                        (index
                          (index_expression
                            (value
                              (built_in_value)))
                          (index_expression
                            (identifier)))))))
                (identifier)
                (type_definition
                  (type))
                (identifier)
                (type_definition
                  (type
                    (type)))
                (statement
                  (expression
                    (value
                      (option)))))))))))
  (statement
    (assignment
      (identifier)
      (assignment_operator)
      (statement
        (expression
          (value
            (structure
              (identifier)
              (structure_instantiator
                (identifier)
                (statement
                  (expression
                    (value
                      (string))))))))))))