What is parser4j

• 100% Java
• It is not a parser generator since it does not generate code.
• it is a kind of lr(∞) parser: perform a bottom-up parsing. It is a ∞ lookahead since it explore possibilities in case of shift-reduce conflict and reduce-reduce conflict. 
• includes lexical analysis.
• it accept ambiguous grammar and output alternative interpretations.
• white space parsing informations are not discard, it is possible to manage white space parsing result. Javadoc example: the comment content have its own grammar. This make able to have nested language.
• The parser is a framework embedded as parsing front end of the using application. It is a framework since:
•  it is call by the parsing application.
• the called parser invoke rule match manager classes provide by application to:
• drive the parsing ( can accept or cancel a match )
• compute data associated to parse nodes, these data are application dependant
• output ( root parse node of the parse tree ) reference application dependant data
• It is composed by:
• main component
• the parser data generator that create a "parser data" from a grammar defined in a text file, the names of classes to invoke for match management are declared in this file.
• the parser framework.
• tools
• the parser data to html that make able to have parser data in human readable form for debug.
• the output parse tree gui shower to analyse output.