JavaPEG

PEG scannerless parser generator for Java 8

What's this?

• A Java parser generator like JavaCC based on Parsing Expression Grammar.
• Outputs pure Java scannerless parser with cache functionality.
• Enables hybrid grammar description by parser class inheritance.
• Eclipse plugin to coloring grammar is available.
• Grammar reference is available here.

Requirements:

• Parser generator requires Java 8 to execute.
• Output parser class may run on Java 7 unless it includes Java 8 features in action code.

Contents:

• JavaPEGPlugin.zip --- Eclipse plugin
  To install: put jar file in 'plugins' folder.
• package parser
• Generator.java --- Parser generator
• GeneratorHelper.java --- Helper class for parser generator
• Parser.java --- Runtime helper class inherited by output parser
• Generator.peg --- Grammar file to create Generator.java
• package parser.bootstrap
• LL1Generator.jj --- JavaCC grammar to create Generator.java
• package sample
• Base.peg --- Simple calculator sample grammar
• Base.java --- Generated parser
• Derived.peg --- Variable assignment extension grammar
• Derived.java --- Generated parser extends Base.java

How to use:

• Just invoke main function of Generator.java, then file chooser dialog will appear.
• Choosing grammar file starts the generation.
• In Eclipse environment, do refresh (F5) and then you can see the created Java file.
• When generating derived parser (e.g. Derived.java), base parser (e.g. Base.java) must be created beforehand.

Unpolished features:

• The generator does not fine check for input grammar.
• Left recursion is not checked and may result in stack overflow.
• Inappropriate grammar like ( symbol? )* is not checked and may result in infinite loop at runtime.