我们可以用C＃编写自己的语言结构吗？

Question

i'd like to know if it is possible to implement own language constructs (like lock or foreach) in C#?

The idea behind is that i want to mark start and end of a block of operations. instead of writing

startblock("blockname");
  blabla();
  andsoon();
endblock();

i'd like to write something like

block("blockname"){
  blabla();
  test();
}

thank you!

Answer 1

No you can't. But there is kind of workaround using IDisposable . You can create a class which will represent block start in constructor and block end in Dispose . Then you wrap the code into using . More here:

• http://blog.functionalfun.net/2008/05/misusing-idisposable-beyond-resource.html
• http://scottbilas.com/blog/bracketing-operations-with-idisposable/

Answer 2

Another option is passing a function to a handler.

private void block(string name, Action action)
{
    startblock(name);
    action();
    endblock();
}

Followed by:

block("blockname", () =>
                {
                    blabla();
                    test();
                });

Keep in mind, this may be an indication that you need an abstract class (or a regular base class), and allow overriding of that method.

Answer 3

For which purpose do you need it? Just for clarity of writing and clean code? C# is not extensible language. With using you can achieve that nicely:

using (new Context("block name"))
{
    // do your staff here
}

class Context : IDisposable
{
    public Context(string name)
    {
        // init context
    }

    public void Dispose()
    {
        // finish work in context
    }
}

Answer 4

Nemerle provides constructs like this. It is not too dissimilar from C#.