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Lambda Notebook: Formal Semantics with Jupyter and Python

This project is a framework for linguists and especially semanticists developing analyses in compositional semantics. It aims to provide a means of developing 'digital fragments', following from the method of fragments in Montague grammar.

The project is in an alpha state. While code is publicly up on github, expect bugs and rapid (or occasionally, not-so-rapid) changes. Contributions, requests, and suggestions are welcome. To see an example, a pre-rendered demo notebook can be found at http://nbviewer.jupyter.org/github/rawlins/lambda-notebook/blob/master/notebooks/Lambda%20Notebook%20Demo%20%28executed%29.ipynb.

The lead developer for this project is Kyle Rawlins, kgr at jhu dot edu. I'm an associate professor in the Cognitive Science Department at Johns Hopkins University, and I do both theoretical linguistic semantics and more computational semantics. My eventual goal is for any theoretical linguistics I do to come with a lambda notebook file. (I'm a long way from that dream.)

While this repository comes with many demo and documentation notebooks, they are mostly saved unexecuted. If you would like to see some samples in nbviewer without downloading anything, the notebook-collection repository mirrors the (non-documentation) notebooks, but they are all pre-executed. Here are four samples. The SVG MathJax renderer is highly recommended for viewing any of these (to select it, right click on any formula).

Installation

See https://github.com/rawlins/lambda-notebook/wiki/Installation

Basically,

  • current release: install from PyPI. (pip install lambda-notebook.)
  • current development version: download the repository and ensure you have Jupyter installed (probably via anaconda). Run ./install_lambda_kernel.py from the repository root to install the kernel.

Getting started

Once you have installed the package, you can then open open lambda notebook files by using the newly installed kernel from any jupyter lab (or notebook) instance. The kernel for regular installs is named Lambda notebook (Python 3), and it can be selected as a new kernel from the launcher, or via the Change Kernel... menu item in the Kernel menu.

Alternatively, with the lamb module installed in the python path, you can run import lamb.auto, which is fully equivalent to loading a notebook with the kernel.

I recommend starting with some of the notebook files in this repository.

  • Lambda Notebook Intro (start here).ipynb
  • Lambda Notebook Demo.ipynb
  • look through the various fragments and tutorials

Upgrading

If you are working from the repository, and have installed the kernel from the repository, you have effectively an "editable install", and the kernel will use the repository version directly.

A note on the lambda notebook UI

  • Lambda notebook is running within the Jupyter notebook framework, and inherits much of the AI. It works in either classic notebook mode or in jupyter lab.
  • Jupyter UI is modal; this can take some getting used to if you aren't familiar with modal editors such as vi. Basically, you are either in edit mode (for editing cells) or command mode (for running cells). Use Enter/esc (or mouse click inside/outside of an edit area) to switch between those. There will be a little pen marker in the upper right corner if you are in edit mode, and the selected cell border will be green. If something isn't doing what you expect, check if you are in the correct mode.
  • Try running through the UI tour (from the help menu of any notebook) to get a sense of the Jupyter UI.

Code overview

There are three main parts to the code, structured into meta and submodules ("meta" for metalanguage), types.py, and lang.py.

  • meta and types.py together provide a typed logical metalanguage somewhat comparable to nltk.sem.
  • lang.py provides machinery for doing composition on an object language.

Two additional files, magics.py and parsing.py provide support for using cell magics in the notebook to directly type expressions in the metalanguage. See the notebooks for demos and documentation.

NLTK

The file tree_mini.py provides nltk.tree, modified to work with the lambda notebook.

See here for NLTK license information (Apache license).