class Rley::SPPF::ParseForest

In an ambiguous grammar there are valid inputs that can result in multiple parse trees. A set of parse trees is commonly referred to as a parse forest. More specifically a parse forest is a graph data structure designed to represent a set of equally syntactically correct parse trees. Parse forests generated by Rley are so-called Shared Packed Parse Forests (SPPF). SPPFs allow very compact representation of parse trees by sharing common sub-tree amongst the parse trees.