text: declare external function LOAD_LUA_LIB
      cstring(200)
      returns integer by value
      entry_point 'load_lua_lib' module_name 'lua_udf';
  
  declare external function MD5
      varchar(4096) character set UTF8 null
      returns varchar(16) character set OCTETS free_it
      entry_point 'md5' module_name 'lua_udf';
  
  declare external function BIN_TO_HEX
      varchar(2048) character set OCTETS null
      returns varchar(4096) character set ASCII free_it
      entry_point 'bin_to_hex' module_name 'lua_udf';
  
  declare external function ASCII_REPLACE_CHARS
      varchar(4096) character set ASCII null,
      varchar(4096) character set ASCII null,
      varchar(4096) character set ASCII null
      returns varchar(4096) character set ASCII free_it
      entry_point 'sbc_replace_chars' module_name 'lua_udf';
  
  declare external function UTF8_REPLACE_CHARS
      varchar(4096) character set UTF8,
      varchar(4096) character set UTF8,
      varchar(4096) character set UTF8
      returns varchar(4096) character set UTF8 free_it
      entry_point 'utf8_replace_chars' module_name 'lua_udf';
  
  declare external function UTF8_REPLACE_BUT_CHARS
      varchar(4096) character set UTF8,
      varchar(4096) character set UTF8,
      varchar(4096) character set UTF8
      returns varchar(4096) character set UTF8 free_it
      entry_point 'utf8_replace_but_chars' module_name 'lua_udf';
  
  declare external function UTF8_MADE_OF
      varchar(4096) character set UTF8,
      varchar(4096) character set UTF8
      returns double precision by value
      entry_point 'utf8_made_of' module_name 'lua_udf';
  
  declare external function UTF8_IS_INTEGER
      varchar(4096) character set UTF8
      returns double precision by value
      entry_point 'utf8_is_integer' module_name 'lua_udf';
  
  declare external function FILE_IS_READABLE
      varchar(2048) character set OCTETS null
      returns integer by value
      entry_point 'file_is_readable' module_name 'lua_udf';
  
  
  