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A tool to generate diagrams for parser grammars


GrammKit is a tool for generating syntax diagrams (also known as railroad diagrams) for parser grammars. Check out the online version.

Currently two grammar formats are supported:

Is uses the railroad-diagrams library to generate SVG images.

Use the command line utility

npm install -g grammkit

To generate static html page run grammkit yourgrammar.peg.

Use the library

npm install grammkit

var grammkit = require('grammkit');
var parse = require('pegjs/lib/parser').parse;
var grammar = parse('start = left ("+" / "-") right');
// => '<svg>...</svg>' 

The SVG renders as:

Diagram Example