================================================================================
empty
================================================================================
CREATE FUNCTION FOO () RETURNS void AS 'select' LANGUAGE sql;
--------------------------------------------------------------------------------

(source_file
  (create_function_statement
    (function_signature
      (identifier)
      (function_parameters))
    (function_return
      (identifier))
    (string)
    (identifier)))

================================================================================
with argument
================================================================================
CREATE FUNCTION FOO (_foo bar.baz) RETURNS void AS 'select' LANGUAGE sql;
--------------------------------------------------------------------------------

(source_file
  (create_function_statement
    (function_signature
      (identifier)
      (function_parameters
        (var_declaration
          (identifier)
          (identifier))))
    (function_return
      (identifier))
    (string)
    (identifier)))

================================================================================
default value
================================================================================
CREATE FUNCTION FOO (_foo bar.baz default '42') RETURNS void AS 'select' LANGUAGE sql;
--------------------------------------------------------------------------------

(source_file
  (create_function_statement
    (function_signature
      (identifier)
      (function_parameters
        (var_declaration
          (identifier)
          (identifier))
        (string)))
    (function_return
      (identifier))
    (string)
    (identifier)))

================================================================================
with arguments
================================================================================
CREATE FUNCTION FOO (foo bar, foo bar) RETURNS void AS 'select' LANGUAGE sql;
--------------------------------------------------------------------------------

(source_file
  (create_function_statement
    (function_signature
      (identifier)
      (function_parameters
        (var_declaration
          (identifier)
          (identifier))
        (var_declaration
          (identifier)
          (identifier))))
    (function_return
      (identifier))
    (string)
    (identifier)))

================================================================================
arrays
================================================================================
CREATE FUNCTION FOO (foo bar[], foo bar[][]) RETURNS void AS 'select' LANGUAGE sql;
--------------------------------------------------------------------------------

(source_file
  (create_function_statement
    (function_signature
      (identifier)
      (function_parameters
        (var_declaration
          (identifier)
          (identifier))
        (var_declaration
          (identifier)
          (identifier))))
    (function_return
      (identifier))
    (string)
    (identifier)))