About

Destate (Discrete Event System Toolkit and inTeractive Environment) is a tool to create and do operations with automata.

Features

• Interactive visualization of the automaton (zoom, translation).
• Interactive creation of the automaton (with command line).
• Save and open automaton as XML files.
• Visualization of the automaton data.
• Multi visualization of automata.
• Support to Deterministic and Non-deterministic.
• (in progress) API for do operations with automata.
  • NFA to DFA conversion.

Installing

The following explains how install the Destate tool.

Requirements

To install Destate you have to satisfy the following dependencies:

• Python: http://www.python.org/.
• PyCairo: http://cairographics.org/pycairo/.
• PyGTK and PyGObject: http://www.pygtk.org/.
• PyDOT: http://code.google.com/p/pydot/ (tested with version 1.0.28).
• GraphViz: http://www.graphviz.org/.

Destate works under Unix, Windows and Mac OS X (these two last are not tested yet, but probably can run without big problems) operating systems.

Download

Get latest version at the GitHub repository.

Using

To start the application you can execute this command:

$ python destate.pyw

If everything is correct, you'll see something like images in the screenshots section. You also may open some examples at share/sample directory.

Commands

To create the automaton you need use the command line interface (or, soon, load XML description file). Bellow we present a table with commands and their descriptions.

Command	Description
do	Do operations with selected automaton.
add	Add states, events or transitions.
del	Delete states, events or transitions.
init	Set the initial state.
mark	Add a finalo state.
unmark	Remove a initial state.

The commands add and del always are followed by a element token (state, event or transition) and a element argument. Before continue with the element arguments we need to define how can be defined a state and a event. In table bellow is discriminated with regular expression valid states and events.

Token	Regular expression
state	[\w]+(,[\w])*
event	[\w]+

If you want to add two states called "A" and "b", an event called "x" and make a transition from "A" to "B" give "x" you must type:

add state A
add state B
add state C
add event x
add lambda A C
add transition A x B

The commands init, mark and unmark are followed by a state token. To set "A" the initial state of the automaton and "B" an final state you must type:

init A
mark C

To remove final state flag from a state you can type unmark instead mark command. And finally, to convert an NFA to a DFA you can just type:

do nfa2dfa

XML

Destate has the capability of read and write XML descriptions of automata. Below an example of a XML automaton description.

<?xml version="1.0" encoding="utf-8"?>
<automaton start="A" name="Example">
    <states>
        <state name="A"/>
        <state name="B" option="final"/>
        <state name="C"/>
    </states>
    <events>
        <event name="x"/>
        <event name="y"/>
        <event name="z"/>
    </events>
    <lambdas>
        <lambda from="A" to="B"/>
        <lambda from="C" to="B"/>
    </lambdas>
    <transitions>
        <transition from="A" when="x" to="A"/>
        <transition from="B" when="x" to="A"/>
        <transition from="C" when="x" to="A"/>
        <transition from="A" when="y" to="B"/>
        <transition from="B" when="y" to="B"/>
        <transition from="C" when="y" to="B"/>
        <transition from="A" when="z" to="C"/>
        <transition from="B" when="z" to="C"/>
        <transition from="C" when="z" to="C"/>
    </transitions>
    <comment>Destate XML example.</comment>
</automaton>

Screenshots

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View source file index.t2t.