=====================================
Using directives
=====================================

using A;
using B.C;
using global::E.F;
using G = H.I;
using static J.K;

---

(compilation_unit
  (using_directive
    (identifier))
  (using_directive
    (qualified_name (identifier) (identifier)))
  (using_directive
    (qualified_name
      (alias_qualified_name (global) (identifier))
      (identifier)))
  (using_directive
    (name_equals (identifier))
    (qualified_name (identifier) (identifier)))
  (using_directive
    (qualified_name (identifier) (identifier))))

=====================================
Nested using directives
=====================================

namespace Foo {
  using A;
}

---

(compilation_unit
  (namespace_declaration
    (identifier)
    (declaration_list
      (using_directive
        (identifier)))))

=====================================
Comments
=====================================

// I'm a single-line comment

/*
 *  I'm a block comment: a * b / c
 */

---

(compilation_unit (comment) (comment))

=====================================
Namespaces
=====================================

namespace A {
  namespace B.C.D {
  }

  namespace E.F {
  }
}

---

(compilation_unit
  (namespace_declaration
    (identifier)
    (declaration_list
      (namespace_declaration
        (qualified_name
          (qualified_name (identifier) (identifier))
          (identifier))
        (declaration_list))
      (namespace_declaration
        (qualified_name (identifier) (identifier))
        (declaration_list)))))

=====================================
Interfaces
=====================================

public interface IFoo {
}

---

(compilation_unit
  (interface_declaration
    (modifier)
    (identifier)
    (declaration_list)))

=====================================
Externs
=====================================

extern alias A;

---

(compilation_unit
  (extern_alias_directive
    (identifier)))


=====================================
Delegates
=====================================

public delegate int Global(ref char a = '\n');

delegate void A<T>() where T:class;

delegate void A(params int [] test);

class Z {
  delegate void Zed();
}

---

(compilation_unit
  (delegate_declaration
    (modifier)
    (predefined_type)
    (identifier)
    (parameter_list
      (parameter
        (parameter_modifier)
        (predefined_type)
        (identifier)
        (equals_value_clause (character_literal (escape_sequence))))))
  (delegate_declaration (void_keyword) (identifier)
    (type_parameter_list (type_parameter (identifier)))
    (parameter_list)
    (type_parameter_constraints_clause (identifier) (type_parameter_constraint)))
  (delegate_declaration (void_keyword) (identifier)
    (parameter_list (parameter_array (array_type (predefined_type) (array_rank_specifier)) (identifier))))
  (class_declaration (identifier) (declaration_list
    (delegate_declaration (void_keyword) (identifier) (parameter_list)))))

=====================================
Var declared equal to integer literal
=====================================

var a = 1;

---
(compilation_unit
  (field_declaration
    (variable_declaration (implicit_type)
      (variable_declarator (identifier)
        (equals_value_clause (integer_literal))))))