Visual and Interactive Tools

Susan H. Rodger

Duke University


View this page in Romanian courtesy of Alexandra Seremina from May 2011.



This research focuses on designing tools for visualizing and interacting with theoretical computer science concepts.

Tools include:

JFLAP 6.0 * - A new version of JFLAP is now available (Sep. 2006). Starting with Version 4.0b14 JFLAP runs in Java 1.5. New features in 6.0 include pumping lemma game, Moore and Mealy machines, and Batch grading. New features in 4.0 include a completely new interface and incorporating both parts from other tools jeLLRap (LL and LR parsing) and Pate (transforming grammars from CFG to CNF, parsing restricted and unrestricted grammars).
To get on the JFLAP mailing list for notices, send email to

JFLAP 3.1 - the Java version of FLAP, is now available (Aug. 1999). New features in 3.1 include regular expressions, including conversions of regular expressions to NFA, and DFA to regular expressions. New features from 3.0 include several conversions from one representation to another. The conversions are nondeterministic finite automaton (NFA) to deterministic finite automaton (DFA), DFA to minimum state DFA, NFA to regular grammar, regular grammar to NFA, nondeterministic pushdown automaton (NPDA) to context-free grammar (CFG), and three algorithms for CFG to NPDA. Two of the CFG to NPDA conversions are useful in studying LL and LR parsing. In addition, you can now slide the labels along the arcs and stretch the loops (grab the dot on top) for more room.

To get on the JFLAP mailing list for notices, send email to rodger.


JAWAA 2.0 - A tool for creating algorithm animations on the web. - software available now to try out. August 2002 * This tool is ready for testing.


Pâté - A tool for parsing restricted and unrestricted grammars and transforming context-free grammers to CNF. - New version of pate is now available (March 2000) *


JAWAA - A tool for creating algorithm animations on the web. - This is the OLD version of JAWAA which will no longer be supported.




jeLLRap - the Java version/combination of LLparse and LRparse * is now available (Jan. 26, 1998). LLparse and LRparse have been combined into one tool. Additional features show the parse tree or a derivation when parsing.


PumpLemma - A tool for experimenting with the Pumping Lemma for regular languages and context-free languages - This is a very old tool from about 1997, and is no longer supported.


FLAP - X Windows version (OLD, try the newer Java Version of FLAP above! It is much easier to install and this is no longer supported.)


LLparse - This version is no longer supported. See the JAVA version called jeLLRap above.


LRparse - This version is no longer supported. See the JAVA version called jeLLRap above.


Creating Xtango or Samba Animations


Obtaining these tools

JFLAP and many of the tools are available on the individual web sites above. Click on the tool and it will take you to the web site with more information.

For some of the OLDER tools and OLDER versions of tools there is an OLD ftp site with OLD source code via anonymous ftp here . Xtango and Samba are available from Georgia Tech here .

Using these tools in Automata Theory Course

We have used FLAP, LLparse and LRparse in CPS 140, Mathematical Foundations of Computer Science, at Duke University. The lecture, lab, and assignments for this course are here for 1998 and here for 1999 . here for 2002 . here for 2003 .

For more information

Current work includes tools for experimenting with grammars, parsing, the conversion of an automaton into an equivalent form, and the animation of algorithms and data structures.

For more information, contact Susan Rodger at Duke Univerity All these tools have been supported by the Lilly Foundation, Rensselaer, and the National Science Foundation DUE-9354791 (transfered to DUE-9596002). Additional funding from NSF to continue this work was under grant DUE-9555084 And now more funding from NSF to continue this work is under grant DUE-9752583. Any opinions, finding and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.

Here are references to my recent papers.



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