This interface allows for the implementation of a streaming pull based parser. A parser that lazily parses the input as the methods are called and only parses the input once, without backtracking. Exercising the parser can be done with the debug.Walk function. The Walk function also returns some debugging output which should be useful in the development of your parser.

Your parser should also be able to handle skipping of some of the input. This happens when the Walk function returns before encountering an io.EOF. The debug.RandomWalk function is useful for testing this type of robustness in your parser.