The Natural Rule Language (NRL)

The Natural Rule Language is language for working with models that attempts a high-wire task: to be machine parseable by a grammar-based automaton, to remain human readability and to stay as close to English as possible. NRL is being used in large-scale projects to:

Validate data feeds by specifying constraint rules
Enrich data
Map between models published in different formats, like XML or CSV

This project is the home of the NRL constraint language and action language specifications.

Small Model Context: Address
Rule "a1"
At most two of the addressComponents have their type equal to AddressComponentType.StreetAddressLine
and exactly one of the addressComponents has its type equal to AddressComponentType.StreetAddressPostcode

Overview

This overview diagram shows which parts of the NRL are currently available. Parts in blue are on this site. The parts in gray are extended developments that have not yet been made available to the public - contact us to discuss!

Resources

The NRL project makes the following resources available, accessible from the menu on the left:

Documentation	The specification and user guides. Start here if you are new to the NRL.
News	Stay up to date! Subscribe to the nrl-news mailing list. Traffic is infrequent, so you won't get swamped.

A Bit of Background

NRL was first conceived by Christian Nentwich as an alternative English-like syntax for the CLiX constraint language for XML. It was extended in partnership with Rob James to become a replacement for OCL, extending its scope. Since then, an action language and features like Java generation have been added.

People who provided feedback and input into NRL include: Dave Carlson, Peter Geraghty and Serdar Sokmen.

Contact

Any questions, write to christian AT modeltwozero.com (Christian Nentwich) or lostamigo AT gmail.com (Rob James).