Xextan PEG parser

The Xextan PEG parser is a work in progress surface syntax parser for the Xextan language, as well as related tools and interfaces.

The interfaces to the parser are:

• parser.html: HTML interface with various parsing options and allowing selecting the desired parser.
• run_parser.js: Command line interface.

Requirements

For generating a PEGJS grammar engine from its PEG grammar file, as well as for running the IRC bot interfaces, you need to have Node.js installed on your machine.

For generating a PEGJS engine, you need to have the Node.js module pegjs installed in the directory, which you can achieve with the command line npm install pegjs.

Building a PEGJS parser

For building the parser (parser.js) from the parser.peg grammar file, you need to use the following command:

node build-parser parser.peg

Running a parser from command line

Here's how to parse the Xextan text "pal nio e tik" with the grammar parser from command line:

node run_parser "pal nio e tik"

The standard grammar parser is used by default, but another grammar engine can be specified.

• The -std flag selects the standard grammar engine.
• -p PATH can be used for selecting a parser by giving its file path as a command line argument.

Additionally, -m MODE can be used to specify output postprocessing options. Here, MODE can be any letter string, each letter standing for a specific option. Here is the list of possible letters and their associated meaning:

• M -> Keep morphology
• S -> Show spaces
• C -> Show word classes
• T -> Show terminators
• N -> Show main node labels
• R -> Raw output, do not prune the tree, except the morphology if 'M' not present.
• J -> JSON output
• G -> Replace words by glosses
• L -> Run the parser in a loop, consume every input line terminated by a newline and output parsed result
• L -> A second 'L' means that run_parser will expect every input line to begin with a mode string (possibly empty) followed by a space, after which the actual input follows.

Example:

node run_parser -m CTN "pal nio e tik"

This will show terminators, word classes and main node labels.