nltk.app.chartparser_app module¶
A graphical tool for exploring chart parsing.
Chart parsing is a flexible parsing algorithm that uses a data structure called a “chart” to record hypotheses about syntactic constituents. Each hypothesis is represented by a single “edge” on the chart. A set of “chart rules” determine when new edges can be added to the chart. This set of rules controls the overall behavior of the parser (e.g. whether it parses top-down or bottom-up).
The chart parsing tool demonstrates the process of parsing a single sentence, with a given grammar and lexicon. Its display is divided into three sections: the bottom section displays the chart; the middle section displays the sentence; and the top section displays the partial syntax tree corresponding to the selected edge. Buttons along the bottom of the window are used to control the execution of the algorithm.
The chart parsing tool allows for flexible control of the parsing algorithm. At each step of the algorithm, you can select which rule or strategy you wish to apply. This allows you to experiment with mixing different strategies (e.g. top-down and bottom-up). You can exercise fine-grained control over the algorithm by selecting which edge you wish to apply a rule to.