PGo

PGo is a source to source compiler to compile PlusCal into Go lang.

Purpose/motivation

PlusCal is a language for specifying/modeling concurrent systems. It was designed to make it easier to write TLA+. In particular, PlusCal can be compiled into TLA+, which can be checked against useful system properties (using the TLC model checker). For example, here is a repository of PlusCal formulations of solutions to the mutual exclusion problem.

Go is a C based language developed by Google for building distributed systems. It has built in support for concurrency with channels, and goroutines, which makes it great for developing distributed systems.

Currently there are no tools that correspond a PlusCal/TLA+ spec with an implementation of the spec. PGo is a tool that aims to connect the specification with the implementation by generating Go code based on a PlusCal specification. PGo enables the translation of a verified PlusCal specification of a distributed system algorithm into a semantically equivalent Go program.

Current status

Actively under development. PGo supports compilation of most uni-process and very simple multiprocess PlusCal algorithms into corresponding compilable and runnable Go code.

See manual.pdf in the repository for a snapshot of the latest version of the manual that details implemented features and several examples.

How it works

PGo is a source to source compiler written in Java. It uses TLA+ toolset to parse PlusCal into an AST, which is then translated to a Go AST, and finally written to a .go file.

How to install

Requirements: IntelliJ, Eclipse, or Ant 1.9

First download/clone the repository

Option 1: Import as an IntelliJ project.

Option 2: Import as an Eclipse project.

Option 3: Execute ant build to compile the project and then execute pgo.sh [options] pcalfile to compile pcalfile.

Dependencies:

• The Plume options library.

• Java Hamcrest.

• The JSON reference implementation.

PGo was tested on JRE 8, JRE 9, and Go 1.10.

How to run

Use pgo.sh to invoke the compiler. Below are the options that the compiler accepts.

$ ./pgo.sh -h
Usage: pgo [options] pcalfile
  -h --help=<boolean>          - Print usage information [default false]
  -q --logLvlQuiet=<boolean>   - Reduce printing during execution [default false]
  -v --logLvlVerbose=<boolean> - Print detailed information during execution  [default false]
  -c --configFilePath=<string> - path to the configuration file, if any

For developers

If you use Eclipse, you should import the code style found in the pgo-code-style.epf file by clicking File -> Import... and selecting the file.

Furthermore, use the Unix text file line delimiter (especially important if you are using Windows) by going to Eclipse's preferences/options, and under General and Workspace set "New text file line delimiter" to be "Unix".

By default Eclipse does not enable assertions. Our projects assume that you have assertions enabled at all times. To globally enable assertions as a default for all projects, go to Window -> Preferences -> Java / Installed JREs. Select the JRE and click "Edit...". In the "Default VM arguments" field, add "-ea"

Usage Documentation

For more details, see manual.pdf in the repository.