DOT Implementation with ANTLR

This project is a Compiler Lab (Winter 2020) Project of Bachelor's Degree of Computer Engineering, Bu-Ali Sina University In this Project, a simple version of the DOT language is implemented using ANTLR.

What is DOT?

DOT is a DSL(domain-specific language) that can describe graphs, either directed or non directed. This is an example of DOT executed with dot2tex(a console program).

What is ANTLR?

ANTLR is a parser generator, a tool that helps you to create a parser. For the installation of ANTLR on your platform, click here.

Phase #1(Defining Grammar)

The grammar is defined with respect to https://graphviz.org/doc/info/lang.html.This is the lexer and this is the parser rules in ANTLR format.

Parse Tree Represntation

To see if the parse tree is created in a way that we want, we can test it against some inputs. This is how you do it:

\\ Lines proceded by $ are command
\\ Lines proceded by > are inpu
$ antlr4 *.g4 -o test
$ javac DOT*.java
$ grun DOT graph
> digraph G {
> subgraph cluster0 {
> style=filled;
> a0 -> a1;
> label = "1";
> }
> subgraph cluster1 {
> node [style=filled];
> b0 -> b1 -> b2 -> b3;
> label = "2";
> }
> start -> a0;}

This is the respected output of the above, that has executed in terminal:

Phase #2 (setting up the listener)

In this phase, a python listener for DOT language will be generated. To make things faster and cleaner for running the command to generate the parser using the ANTLR tool, a Gradle script is used. Click here to see the code.

./gradlew generateparser

This command generates a lexer and parser file in python, and a listener template file is called DOTParserListener.py. We override its function in another file called GraphDOTListener.py rather than changing its code directly. This is a simple Listener that supports some features of the DOT Language. It uses a python package is called Networkx for representing and manipulating the graph. There is a simple method in the GraphDOTListener class that uses Matplotlib to show the graph with the use of Netwrokx draw function.

main.py is a simple programm that gets input file from the system input and uses the listener to show the result. This is a simple input and its output.

Phase #3(Web application)

In this Phase, a simple web application is implemented with the use of Dash. To run the app, first install the required packages using the following command:

pip install -r requirements.txt

Then run the src/main-generated/web-app.py using following command:

python src/main-generated/web-app.py

Then open the following url is shown in the terminal. this is how the application work-->