http://code.google.com/p/protoc-gen-docbook/
A protobuf plugin that converts a .proto file into DocBook and PDF. This should be one of the first documentation tools for protobuf.
Here are some sample output:
http://code.google.com/p/protoc-gen-docbook/wiki/Samples
Behind the scene, it uses Protobuf compiler plugin architecture to receive the parsed information and convert the proto file into DocBook format. Then Apache FOP is used to convert DocBook into a PDF file. I tried to make this as user friendly as possible. Out of the box, you just need to drop your .proto source file into the deployment folder, run a provided script, and it will generate the DocBook and PDF output.
If it is not too much trouble, please add this into http://code.google.com/p/protobuf/wiki/ThirdPartyAddOns
Feedback is always welcomed.
Thanks
... Alan