Question: How can I use at-exp to include blew raw string:

```
package foo

}

import (

```

I write like this, but it cannot include the "}" character:

```
#lang at-exp racket/base

    (define code @S{
        package foo

        }

        import (
    }

```

How to include special character like "{}" in the raw part.

Answer: 
Use `@S|{...}|` for that: since the closing part is `}|`, plain `}`s would not be special. Also, remember to use `|@` instead of just `@` for nested forms. And if you need another different quotation since you want to use `}|`s too, you can add more things between, as in `@S|==={...}===|`. See the [documentation page](http://docs.racket-lang.org/scribble/reader.html) for details (look for `|{`s, and see [section 2.4.1](http://docs.racket-lang.org/scribble/reader.html#%28part._alt-body-syntax%29)).

As for what you've found: this is not the same. What you're doing there is a nested `"{"` string, which you can use for each unbalanced character. But that is much less convenient than the above alternative quotation syntax.
oh, sorry, I find use @|"{"| is ok.