Coldfusion局部范围外的函数？ [英] Coldfusion Local scope outside of a function?

问题描述

在函数之外定义的局部作用域是什么？

考虑下面的代码：

 < cfscript> 
 
 local.madVar2 =本地作用域变量; 
 
 function madness（）{
 var madVar =madness variable; 
 madVar2 =疯狂二变量; 
 
 writeOutput（local：< BR>）; 
 writeDump（local）; 
 writeOutput（=====================================< BR）; 
 
 writeOutput（local.madVar2：< BR>）; 
 writeDump（local.madVar2）; 
 writeOutput（< BR> ======================================= ==< BR>）; 
 
 writeOutput（madVar2：< BR>）; 
 writeDump（madVar2）; 
 writeOutput（< BR> ======================================= ==< BR>）; 
 
 writeOutput（variables.madVar2：< BR>）; 
 writeDump（variables.madVar2）; 
 writeOutput（< BR> ======================================= ==< BR>）; 
} 
 
< / cfscript> 
  

通过添加 var 关键字更改madVar2赋值，

  function madness（）{
 var madVar =madness variable; 
 var madVar2 =madness two variable; 
  

将产生此输出：

img src =https://i.stack.imgur.com/WJnKY.pngalt =Image 2>

解决方案

Local 作用域仅在函数内定义，不应在其外部使用。

函数，默认为变量范围。

  // 
 myVar = 0; 
 //将与
相同variables.myVar = 0; 
  

当你引用 local.madVar2 ，它在函数之外初始化，实际上是指变量作用域中的 local.madVar2 madVar2 存储在名为 local 的结构中，该结构存储在变量 scope。

因此，在适当的范围设定下，您的代码将被视为：

  writeOutput（variables.local.madVar2：< BR>）; 
 writeDump（variables.local.madVar2）; 
  

在定义后尝试转储 variables 函数内的变量：

  var madVar =madness variable; 
 madVar2 =疯狂二变量; 
 writeDump（variables）; 
 ..... 
  

您将看到变量如何落入范围。 p>

What exactly is the local scope defined outside of a function?

Consider the following code:

<cfscript>

    local.madVar2 = "Local scope variable";

    function madness() {
        var madVar = "madness variable";
        madVar2 = "madness two variable";

        writeOutput("local: <BR>");
        writeDump(local);
        writeOutput("========================================= <BR>");

        writeOutput("local.madVar2: <BR>");     
        writeDump(local.madVar2);
        writeOutput("<BR>========================================= <BR>");

        writeOutput("madVar2: <BR>");       
        writeDump(madVar2);
        writeOutput("<BR>========================================= <BR>");

        writeOutput("variables.madVar2: <BR>");     
        writeDump(variables.madVar2);
        writeOutput("<BR>========================================= <BR>");
    }

</cfscript>

Changing the madVar2 assignment by adding the var keyword, like this:

function madness() {
    var madVar = "madness variable";
    var madVar2 = "madness two variable";

Will yield this output:

解决方案

The Local scope is only defined within functions and should not be used outside of it.

Variables defined outside the functions, default to the variables scope.

//that way
myVar = 0;
//will be the same as
variables.myVar = 0;

When you refer to local.madVar2 variable, which was initialized outside the function you're essentially referring to the local.madVar2 in the variables scope i.e the variable madVar2 is stored inside a struct named local which is stored in the variables scope.

So essentially, with the proper scoping in place your code is treated as:

writeOutput("variables.local.madVar2: <BR>");     
writeDump(variables.local.madVar2);

Try dumping the variables scope just after defining the variables inside the function as:

var madVar = "madness variable";
madVar2 = "madness two variable";
writeDump(variables);
.....

You will see how the variables fall into scopes.

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