debug.getinfo([thread],function[,what])
function,可以是一个数,0代表(getinfo),1代表调用getinfo的函数,如果超出调用堆栈函数返回nil.
what,可以是下面的字符或者它们的组合,getinfo将根据what来填充返回的表.
'n'填充name和namewhat字段
'S'填充source,short_src,linedefined,lastlinedefined和what
'l'填充currentline,函数当前执行.
'u' 填充nups,函数的upvalue数量.
'f'填充func,level对应的函数.
'L' pushes onto the stack a table whose indices are the numbers of the lines that are valid on the function. (A valid line is a line with some associated code, that is, a line where you can put a break point. Non-valid lines include empty lines and comments.)
debug.getfunv(o)
返回对象o的环境.如果这样使用debug.getfunv(debug.getinfo(level,'f').func)就可以访问level的环境表.