latex2py 0.1.3

A lightweight LaTeX-to-Python parser

LaTeX-to-Python Parser (latex2py)

This is a lightweight LaTeX-to-Python parser.

We needed a parser that could convert LaTeX math expressions into Python-like expressions. However, SymPy is an extremely large library (~50 MB) and leads to bundle size issues when deploying code as an AWS lambda function (max. size 250MB). This codebase strips out the minimal code that we need, and is around ~200kb in size.

The parser is inspired by the sympy LaTeX parser, but instead of returning symbolic SymPy expressions, we return lines of Python-like code which could can then be evaluated in the interpreter.

Setup

Run poetry install to create a virtual environment and install dependencies.

You can also run poetry shell to activate the virtual environment.

Usage

from latex2py.parser import parse_latex

latex = r'\frac{1}{2} + \frac{3}{4}'
python = parse_latex(latex)
print(python) # "(1 / 2) + (3 / 4)"

# You can also evaluate the expression
result = eval(python)
print(result) # 1.25

Limitations

• Integrals and derivatives are not supported yet.
• The \\sum and \\prod commands are mapped to special Sum() and Product() functions that the calling code will have to implement. See the tests for examples.
• Strings like hello are interpreted as implicit multiplication, so hello will be interpreted as h * e * l * l * o. This is a limitation of the parser, and you will have to handle this case in your code. In a future version, we may want to add a flag that determines whether this is implicit multiplication or a variable name.

You can also adjust the parsing behavior using the Config object - see latex2py/config.py for more details.

Tests

Run pytest tests to run the test suite. You can find examples of parseable LaTeX syntex there too.

Re-Generating the Grammar (Advanced)

If you make changes to LaTeX.g4, you will need to regenerate the parser using the following commands:

pip install antlr4-tools
# This will download the antlr4 jar file if you don't have it already.
antlr4 LaTeX.g4 -o gen

The generated files will be in the gen directory.