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Human-Readable Text Form for UML Activity Diagrams

This effort has produced (1) a notation to render Activity Diagrams as defined by the Unified Modeling Language (UML) into human-readable text, and (2) a parser to validate the notation and facilitate its use as an input format by software. The notation was developed by modifying the Petri Net Linear Form (PNLF).

A human-readable text form of Activity Diagrams may be used for any number of reasons, such as:

  • Graphical representations require special tooling to work with, are time-consuming to create, require conversion for embedding in e-mail or documents, take up a lot of space on a screen, and are often resistant to standard searching or copy/paste operations.

  • Graphical representations are not processable by screen readers (assistive technology that converts documents to speech).

  • For a programmer who is building new applications, getting a prototype running with a human-readable text format for input or output takes significantly less up-front investment of effort than starting out with a graphical representation or a full-featured interchange format.

  • Extensible Markup Language (XML) based languages are cumbersome to use for this purpose because XML syntax rules prevent the definition of specialized punctuation and force graphically adjacent elements to be separated from one another more often than a specialized notation would.

The parser is freely available for download. A technical report that defines the notation is available as NISTIR 7469 [pdf].


For more information contact: David Flater (


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Created on 08/10/2007
Last Modified: Thursday, 11/29/2007 12:52 PM
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