Introducing the EXPRESS Language Foundation

Author’s picture Thomas Thurman Author’s picture Hiroshi Murayama Author’s picture David Loffredo Author’s picture Ronald Tse on 18 Mar 2022

We are happy to announce the establishment of the EXPRESS Language Foundation.

The EXPRESS Language Foundation, or just “ELF”, is a non-profit organization to facilitate the education, standardization, research, promotion, definition, usage of information modelling and programming languages, with a focus on the EXPRESS language family.

What is EXPRESS?

Purpose of EXPRESS

EXPRESS is an information modelling language that has been powering what is now called "smart manufacturing". The language originated from the PDDI program, which was created in 1982 by the US Air Force at McDonnell Aircraft (now merged into Boeing).

The raison d’être of EXPRESS is reflected in its name — to facilitate “expressiveness” in modelling information.

Today, EXPRESS is heavily used in advanced manufacturing, including in the industries of:

  • aerospace

  • automotive

  • construction

  • digital twins

  • smart manufacturing

Since then, EXPRESS has now grown into a family of information modelling languages, including EXPRESS-G, EXPRESS-I and EXPRESS-X, collectively referred to as the “EXPRESS language family”.

There are a few properties that separate EXPRESS from other information modelling languages:

  • It is a machine-readable language.

  • It is a data modelling language — not a programming language, even though it does provide algorithmic functionality

The EXPRESS language family

Each member of the EXPRESS family of languages provides specific functionality for the information modeller:

  • EXPRESS provides a lexical syntax for modelling information

  • EXPRESS-G provides a graphical syntax for modelling information, mirroring a subset of EXPRESS syntax

  • EXPRESS-I provides a lexical syntax for information model instances

  • EXPRESS-X provides a lexical syntax for mapping between information models

Standardization of EXPRESS

Given that EXPRESS was immensely useful for the manufacturing supply chain, it entered a standardization process at the National Bureau of Standards (now NIST) in 1984.

In 1986, EXPRESS was proposed by NBS to be an International Standard at ISO, which the language specification was ultimately published in 1994 as ISO 10303-11:1994.

In 1994, prior to its standardization, the first authoritative reference and manual on EXPRESS was published by Doug Schenck and Peter Wilson, the original inventor of EXPRESS and EXPRESS-G/EXPRESS-X respectively.

In 2004, the second edition of the language reference ISO 10303-11:2004 was published at ISO, with David Loffredo and Peter Wilson as its project leaders.

Doug, Peter and Dave are all founding members of ELF.

The role of ELF

EXPRESS has already been standardized and is widely used. Why does the EXPRESS language need to be supported by an organization?

The EXPRESS Language Foundation is established in response to user needs of the EXPRESS language family, juxtaposed upon the current technology and usage environment that places additional demands on the language family not previously addressed. Linguists consider languages as living things, and members of the EXPRESS language family are no different!

ELF, being a non-profit organization, is able to receive donations and grants to fund future development and maintenance of the EXPRESS family of languages, as well as be able to support users of the languages.

Specifically, ELF aims to:

  1. develop and publish best practices, documentation and related tools for the definition, relation, usage, governance and dissemination of information models;

  2. foster and host a user community for those who work with the EXPRESS language family.

Target beneficiaries

For those who remember, the EXPRESS User Group (EUG) has held annual conferences since 1991 until 1996. Peter Wilson, the main organizer of EUG, is one of the founders of ELF.

ELF takes the baton from EUG in the 21st century in the following ways:

  • Foster and support EXPRESS user communities (role of EUG)

  • Educate EXPRESS users, providing training resources

  • Develop and standardize the EXPRESS language family

  • Promote usage and adoption of the EXPRESS language family

  • Ensure that EXPRESS remains relevant and useful now and beyond

ELF serves organizations and individuals alike with a need in defining interchangeable information models across information systems.


ELF is an international standardization organization, similar to the roles played by ISO and IEC.

ELF creates international standards and contributes to the domains of information modelling, abstract languages and data management, relating to the understanding of shared data and the relationships between them, specifically for the EXPRESS language families.

Governance structure

ELF consists of a board and members of the organization. Our members are organized into a central office with multiple technical committees:

  • The central office functions to support the activities of technical committees, including for the publication of standards.

  • Technical committees are organized by volunteers who are experts in a selected domain of the technical committee and develop best practices and information for the international arena.

International cooperation

The mission of ELF is international in nature, given that its founding team is spread across the globe.

ELF consists of international experts and will work with international partners.

Join us at ELF!

The founding members of ELF include the original inventors of EXPRESS, Doug Schenck, Bernd Wenzel, Peter Wilson; experts involved in enhancing EXPRESS, David Loffredo, Allison Barnard Feeney, Phil Spiby; as well as EXPRESS stakeholders deeply interested in the achievement of the Foundation’s mission, Thomas Thurman, Hiroshi Murayama and Ronald Tse.

ELF is now welcoming organizational and individual members.

Join us in making EXPRESS better!