Is there a language/format that allows to define an API in XML?

I think I have开发者_开发技巧 seen a format/language where you write in XML and it defines an API to program against. I want to do this so that people can benefit from it since having a PDF/online API may not always be enough (think about IDEs).

Is there a common language in which you can write your API?

Edit: I'll try to be more clear. I have an API. I have an online API documentation for it. However, I want IDEs and programs to be able to understand it better since RegEx'ing my online documentation isn't going to work for them.

Edit: Here's an example of what I'd like to produce: view-source:http://api.jquery.com/api/

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If you create Web Services for your API, you can generate a WSDL file which is an XML description of the service. Many languages/frameworks have tools to generate proxy classes from a WSDL.

More info on WSDL: http://www.w3.org/TR/wsdl