Question

我想知道是否有一种方法可以加载＆＃39;函数从局部变量而不是全局变量获取变量值？

说我有这样的字符串＆＃39; trade.version == 2＆＃39;我想用＆＃39; load＆＃39;来执行函数内部以交易为参数。

function doTest( trade, test )
  -- inside the string 'test', I would like that any reference to 'trade'
  -- refer to the function parameter instead of a global variable
  if ( assert(load("return "..test))() ) then
    -- do something
  end
end

a_userdata = { version = 2 }
-- Calling the function above
doTest( a_userdata , "trade.version == 2" )

[string "return trade.version == 2"]:1: attempt to index global 'trade' (a nil value)
stack traceback:
    [string "return trade.version == 2"]:1: in main chunk
    stdin:2: in function 'doTest'
    stdin:1: in main chunk
    [C]: in ?

作为一种解决方法，我已经定义了一个全局变量，它的工作非常好。但我想避免这个全局变量。

非常感谢

Answer 1

function doTest( trade, test )
  -- inside the string 'test', I would like that any reference to 'trade'
  -- refer to the function parameter instead of a global variable
  if assert(load("local trade = ...; return "..test))(trade) then
    -- do something
    print('Yes, version equals to 2')
  end
end

a_userdata = { version = 2 }
-- Calling the function above
doTest( a_userdata , "trade.version == 2" )

通过＆＃39; load＆＃39;

1 个答案: