A parse tree is a tree representation of the result of parsing a list of characters. A real parse tree contains the full inputstream. It then allows a yield operation that results in the original input.

A parse tree is closer to the input than an abstract syntax tree. The information in a parse tree usually includes layout and comments, where abstract syntax trees usally consider this information to be irrelevant.

The AsFix format is a format for representing parse trees in the Stratego.ATerm^? format.