library for input text with sample code

I want to implement a forum system on a programming site and am not finding a library that will fit me to format the content of this text area that we use to write our questions and answers. I've seen numerous editors, but they give options as if it were a standard text editor like word, and I just wanted some options being required citation and sample code and image insertion. Just like what happens here. But I did not find any library to give me this code sample (it's the function that uses this {symbol} in this editor we're using now on this site). Does anyone know a lib to tell me?