NOTE: jeLLRap is no longer supported. Instead it has been incorporated into the tool JFLAP . With JFLAP you can build SLR(1) parse tables and LL(1) parse tables. See JFLAp for more info.

What is it?
JELLRAP is a graphical tool written for people who wish to parse strings using a variety of algorithms: LL1, LL2, or LR1. It is the Java version of LLParse and LRParse combined into a single tool that will run on multiple platforms. LLParse and LRParse were written in C/C++ and run only on an X-windows environment. If you are currently running LLParse and LRParse and are wondering if you should upgrade, here are some changes that may help you decide:

Written in Java, so it is easier to install
Is a single tool so you can switch between LL and LR with ease
Similar look and feel -- even maintains the same keyboard shortcuts
Bug fixes were made to the LL2 Parser
Improved graphics for DFA and trees
New feature to show the rules in a derivation
Can TAB through grammar production rules instead of aligning the mouse

LL1 vs LL2 vs LR1
The first L is for parsing input from left to right and the second L is for using leftmost derivations. JELLRAP supports both LL1 parsing and LL2 parsing whereby the 1 and 2 indicates the number of lookahead symbols. For the R in LR1 stand for using the rightmost derivation and JELLRAP only supports using 1 look ahead symbol.

Can I see it first?
Screen Shots
Sneak Preview!! (if your browser can support a Java 1.1 Applet)

How do I get my own?
Read the README file and then Download the whole package from here (including the source code):
ftp://ftp.cs.duke.edu/pub/rodger/tools/jellrap.12-97.tar.gz (any platform)

Developers
Javadoc documentation
Simplified class diagram

JELLRAP was written by undergraduates at Duke University, Alex Karweit and Robyn Geer, headed by Prof. Susan Rodger, and financed by a grant from the National Science Foundation.