Piqi is a set of languages and open-source tools for working with structured data. It includes:

• A cross-language data serialization system compatible with Google Protocol Buffers. It allows programs implemented in various languages to exchange and persist data in a portable manner.

• Piq -- a human-friendly typed data representation language. It is designed to be more convenient for representing, viewing and editing data than JSON, XML, CSV, S-expressions and other formats.

• Piqi -- a universal data definition language. It can be used as a schema language for JSON, XML, Protocol Buffers and Piq.

• Tools for validating, pretty-printing and converting data between Piq, JSON, XML and Protocol Buffers formats.

• Piqi-RPC -- an RPC-over-HTTP system for Erlang. It provides a simple way to expose Erlang services via JSON, XML and Google Protocol Buffers over HTTP.

As a data serialization system, Piqi implements native support for OCaml and Erlang. Connectivity with other programming languages is provided via Google Protocol Buffers. Overall, Piqi provides a more natural mapping to functional programming languages compared to various serialization systems that were originally designed for imperative or object-oriented languages.

Piqi was inspired by Google Protocol Buffers and specially designed to be largely compatible with it. Like Protocol Buffers, Piqi relies on type definitions and supports data schema evolution. The main difference is that Piqi has a richer data model, high-level modules and a powerful data representation language (Piq).

Combination of the data representation (Piq) and the data definition (Piqi) languages is similar to the concept of "valid XML" (i.e. XML conforming to some XML Schema). However, unlike XML, Piq has a concise, clean syntax and a data model similar to those of high-level programming languages.

Full project description and documentation can be found at http://piqi.org

Installation

See INSTALL for the installation instructions.

Bug tracker

If you found a bug or have any suggestions please submit a GitHub issue: https://github.com/alavrik/piqi/issues

Contributing

Participation and patches are very welcome! The best way to submit a contribution is to open a pull request on GitHub against the master branch.

Mailing list

For discussions about the usage, development, and future of Piqi there is the Piqi Google Group: http://groups.google.com/group/piqi

License

Apache License Version 2.0

Files

README                this file
INSTALL               general installation instructions
INSTALL.erlang        instructions for building Piqi for Erlang
INSTALL.ocaml         instructions for building Piqi for OCaml
INSTALL.windows       instructions for building Piqi on Windows
setenv.sh             environment configuration for running tests
setenv-mingw.sh       environment configuration for Windows/MinGW builds
LICENSE               license
NOTICE                copyright notice
CHANGES               release history
VERSION               current version
configure             configure script
Makefile              top-level Makefile
make/                 makefiles and build scripts
deps/                 third-party components (see NOTICE for details)
piqi-camlp4/          Piqi syntax extensions for OCaml
piqicc/               Piqi compiler compiler (used only during boostrap)
piqic/                Piq interface compiler(s) for OCaml
piqi-tools/           "piqi" command-line utility (piqi tools)
piqi                  Piqi self-specification
piqilib/              Piqi common library
piqirun-ocaml/        Piqi runtime library for OCaml
examples/             examples
tests/                tests for various piqi functionality; see tests/README
doc/                  Piqi documentation
editors/              text editor plugins for .piq and .piqi files