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The NIST EXPRESS Toolkit: Updating Existing Applications



Donald E. Libes


The NIST EXPRESS Toolkit is a software library for building EXPRESS-related tools. The toolkit was previously released in 1991, based on EXPRESS N14. The current release is based on N151 and while the philosophical underpinnings are similar, much of the interfaces have changed significantly. This paper describes changes that must be made to extant applications so that they can work with the new toolkit.

This paper should be read by anyone maintaining software based upon the NIST EXPRESS toolkit. This paper will also provide insight to people interested in the internals of EXPRESS implementations and some of the ways they have changed over time due to experience and the different EXPRESS specifications.

NIST Interagency/Internal Report (NISTIR) - 5205
Report Number


compiler, Express, implementation, National PDES Testbed, PDES, STEP


Libes, D. (1993), The NIST EXPRESS Toolkit: Updating Existing Applications, NIST Interagency/Internal Report (NISTIR), National Institute of Standards and Technology, Gaithersburg, MD, [online], (Accessed April 18, 2024)
Created January 1, 1993, Updated November 10, 2018