Pomagma

Pomagma is an inference engine for extensional untyped λ-calculus. Pomagma is useful for:

• simplifying code fragments expressed in pure λ-join calculus
• validating entire codebases of λ-terms and inequalities
• testing and validating systems of inequalities
• solving systems of inequalities

Pomagma has client libraries in python and node.js, and powers the Puddle reactive coding environment. The correctness of Pomagma's theory is being verified in the Hstar project.

Documentation

• Philosophy
• Using a client library
• Administering a server

Installing

The server targets Ubuntu 14.04 and 12.04, and installs in a python virtualenv.

git clone https://github.com/fritzo/pomagma
cd pomagma
. install.sh
make small-test     # takes ~5 CPU minutes
make test           # takes ~1 CPU hour

Client libraries support Python 2.7 and Node.js.

pip install pomagma
npm install pomagma

Quick Start

Start a local analysis server with the tiny default atlas

pomagma analyze       # starts server, Ctrl-C to quit

Then in another terminal, start an interactive client session

pomagma connect       # starts client session

Alternatively, connect using the Python client library

python
from pomagma import analyst
with analyst.connect() as db:
    print db.simplify(["APP I I"])      # prints [I]
    print db.validate(["I"])            # prints [{"is_bot": False, "is_top": False}]

or the Node.js client library

nodejs
var analyst = require("pomagma").analyst;
var db = analyst.connect();
console.log(db.simplify(["APP I I"]));  // prints [I]
console.log(db.validate(["I"]));        // prints [{"is_bot": false, "is_top": false}]
db.close();

Get an Atlas to power an analysis server

Pomagma reasons about large programs by approximately locating code fragments in an atlas of 103-105 basic programs. The more basic programs in an atlas, the more accurate pomagma's analysis will be. Pomagma ships with a tiny default atlas of ~2000 basic programs.

To get a large prebuild atlas, put your AWS credentials in the environment and

pomagma pull                  # downloads atlas from S3 bucket

To start building a custom atlas from scratch

pomagma make max_size=10000   # kill and restart at any time

Pomagma is parallelized and needs lots of memory to build a large atlas.

| Atlas Size | Compute Time | Memory Space | Storage Space | |---------------|--------------|--------------|----------------------| | 1 000 atoms | ~1 CPU hour | ~10MB | ~1MB uncompressed | | 10 000 atoms | ~1 CPU week | ~1GB | ~100MB uncompressed | | 100 000 atoms | ~5 CPU years | ~100GB | ~10GB uncompressed |

License

Copyright 2005-2015 Fritz Obermeyer. All code is licensed under the Apache 2.0 License.