JSGF Grammar Tools

A Python library for parsing and generating strings from JSGF (Java Speech Grammar Format) grammars. This modernized version supports Python 3.7+ and includes comprehensive testing.

Features

• Parser: Convert JSGF grammar files into abstract syntax trees
• Deterministic Generator: Generate all possible strings from non-recursive grammars
• Probabilistic Generator: Generate random strings using weights and probabilities
• Modern Python: Full Python 3.7+ support with type hints and proper packaging
• Comprehensive Testing: Full test suite with pytest

Installation

From Source

git clone https://github.com/syntactic/JSGFTools.git
cd JSGFTools
pip install -e .

Development Setup

git clone https://github.com/syntactic/JSGFTools.git
cd JSGFTools
pip install -r requirements-dev.txt

Quick Start

Command Line Usage

Generate all possible strings from a non-recursive grammar:

python DeterministicGenerator.py IdeasNonRecursive.gram

Generate 20 random strings from a grammar (supports recursive rules):

python ProbabilisticGenerator.py Ideas.gram 20

Python API Usage

import JSGFParser as parser
import DeterministicGenerator as det_gen
import ProbabilisticGenerator as prob_gen
from io import StringIO

# Parse a grammar
grammar_text = """
public <greeting> = hello | hi;
public <target> = world | there;
public <start> = <greeting> <target>;
"""

with StringIO(grammar_text) as f:
    grammar = parser.getGrammarObject(f)

# Generate all possibilities (deterministic)
det_gen.grammar = grammar
rule = grammar.publicRules[2]  # <start> rule
all_strings = det_gen.processRHS(rule.rhs)
print("All possible strings:", all_strings)

# Generate random string (probabilistic)
prob_gen.grammar = grammar
random_string = prob_gen.processRHS(rule.rhs)
print("Random string:", random_string)

Grammar Format

JSGFTools supports most of the JSGF specification:

// Comments are supported
public <start> = <greeting> <target>;

// Alternatives with optional weights
<greeting> = /5/ hello | /1/ hi | hey;

// Optional elements
<polite> = [ please ];

// Nonterminal references
<target> = world | there;

// Recursive rules (use with ProbabilisticGenerator only)
<recursive> = base | <recursive> more;

Supported Features

• Rule definitions and nonterminal references
• Alternatives (|) with optional weights (/weight/)
• Optional elements ([...])
• Grouping with parentheses
• Comments (// and /* */)
• Public and private rules

Not Yet Supported

• Kleene operators (* and +)
• Import statements
• Tags

Important Notes

Recursive vs Non-Recursive Grammars

• DeterministicGenerator: Only use with non-recursive grammars to avoid infinite loops
• ProbabilisticGenerator: Can safely handle recursive grammars through probabilistic termination

Example of recursive rule:

<sentence> = <noun> <verb> | <sentence> and <sentence>;

Testing

Run the test suite:

pytest test_jsgf_tools.py -v

Run specific test categories:

pytest test_jsgf_tools.py::TestJSGFParser -v      # Parser tests
pytest test_jsgf_tools.py::TestIntegration -v     # Integration tests

Documentation

For detailed API documentation, build the Sphinx docs:

cd docs
make html

Then open docs/_build/html/index.html in your browser.

Example Files

• Ideas.gram: Recursive grammar example (use with ProbabilisticGenerator)
• IdeasNonRecursive.gram: Non-recursive grammar example (use with DeterministicGenerator)

Contributing

1. Fork the repository
2. Create a feature branch
3. Make your changes
4. Add tests for new functionality
5. Run the test suite: pytest
6. Submit a pull request

License

MIT License. See LICENSE file for details.

Version History

• 2.0.0: Complete Python 3 modernization, added test suite, improved packaging
• 1.x: Original Python 2.7 version