Lark Run

A simple command-line interface for Lark, the parsing Library.

Installation

You can install Lark Run using pip:

pip install lark-run

Or let uv or pipx handle it for you:

uvx lark-run YOUR_FILE.lark  # install automatically in the background

Usage

To use Lark Run, simply run the command followed by the path to your Lark grammar file:

lark-run YOUR_FILE.lark

This will open a REPL where you can enter strings to be parsed according to the grammar defined in YOUR_FILE.lark. The CLI will display the parse tree for each input string.

You can also specify a test input file containing strings that should be accepted or rejected by the grammar:

lark-run YOUR_FILE.lark -t TEST_INPUTS.yaml

It expects a YAML or JSON file with the following structure:

accept:
  - "valid string 1"
  - "valid string 2"    
reject:
    - "invalid string 1"
    - "invalid string 2"