显然，第一个代码块是一个函数声明，定义了名为ToggleSyntax的函数，它没有包含任何参数。

The first block of code is obviously a function declaration, defining a function named ToggleSyntax , which takes no arguments.

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这里的代码使用了一个局部变量diff，这个局部变量只定义在这一块代码范围内，之后在构造函数中又声明了另一个相同级别的变量fill。

The code here USES a local variable diff, which is only defined within this block of code, while later in the constructor a separate variable, fill, is declared at the same level.

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