function provideSum() {
    return Blockly.Lua.provideFunction_(
        'math_sum',
        ['function ' + Blockly.Lua.FUNCTION_NAME_PLACEHOLDER_ + '(t)',
         '  local result = 0',
         '  for _, v in ipairs(t) do',
         '    result = result + v',
         '  end',
         '  return result',
         'end']);
  }
@fileoverview Generating Lua for math blocks.
@author rodrigoq@google.com (Rodrigo Queiro)