Awhile back over at the Yahoo! Developer Network there was this interesting post on WADL highlighting yet another acronym, but something potentially quite useful here. What's WADL? It stands for Web Application Description Language, a project being managed over at Java.net, with homepage here. Sun's Marc Hadley describes it concisely in this article:
WADL is designed to provide a simple alternative to WSDL for use with XML/ HTTP Web applications. To date such applications have been mainly described using a combination of textual description and XML schema, WADL aims to provide a machine process-able description of such applications in a simpler format than is possible using WSDL.
Just this month Thomas Steiner started working on Google REST Compile and REST Describe. REST Compile will read a WADL description and output code in a variety of languages and REST Describe will be a tool for creating WADL based on text Documentation. Below is Thomas' diagram showing the REST Compile flow. [via]
With hundreds of REST-based APIs listed here there might be a role for WADL or similar standards and tools.