Runi

Runi is a context-free grammar, lexer and predictive recursive descent parser for a C-like language in Go.

Motivation

This implementation is a part of our laboratory project to implement lexical and syntax analyzers at BITS Pilani. We also wanted to go out of our comfort zone and choose a modern language that we had not tried before.

EBNF Grammar

Dependencies

• gographviz, to generate the DOT specification
• Graphviz, to generate the image from the DOT specification

Usage

Please run $ go run . [file] where [file] represents an optional argument (which defaults to test.txt) to parse the file. If the parser accepts the program, it will generate a DOT specification of the parse tree depicting the leftmost derivation in out.dot. This specification can be run through Graphviz to generate the parse tree. We recommend doing $ dot -Tpng -Gdpi=300 out.dot -o out.png.

Lexer Testing

Input files for our lexer's test suite can be found in src/tests/. Please do go test to run the tests.

Visualizations

Here are some sample generated visualizations from images/. The program source is shown at the top of the image.

Authors

Rupanshu Soi & Nipun Wahi, Department of Computer Science, BITS Pilani - Hyderabad Campus, India.

Why "Runi" ?

"Rupanshu Soi"[:2] + "Nipun Wahi"[:2]

References

• Writing An Interpreter in Go by Thorsten Ball