The Natural Rule Language (NRL) - Details

The Natural Rule Language provides a representation that is close to English for common tasks in system integration:

Validation rules for data, such as XML or databases
Action rules for data enrichment, and translation between data formats

NRL aims to provide an executable specification of a system. It is readable, yet has a formal interpretation, and code can be generated directly from it. It is also model-driven: NRL rules refer directly to elements in UML models, XML Schemas or other suitable models.

Is it Proprietary?

The language is open - the NRL specifications are freely available on http://nrl.sourceforge.net. The parser for the constraint language is also freely available. You can use these to map NRL to any execution platform you like.

Model Two Zero provides a number of industrial-strength tools for working with NRL. These are used world-wide in production projects in the capital markets area. This also includes an editor for model-to-model mappings.

Why NRL?

Business/data analysts can read and write it; we have completed several fairly complex integration projects this way
It is easy to read and even if you drop NRL, your system remains clearly documented
It saves time; NRL is easy to write once you are familiar, and code is generated directly
It makes a great handover artifact to off-shore locations. Business experts can write the specification in NRL, and developers can slot it into an operational architecture
It can be translated to different execution or specification languages - the entire component set is aimed at facilitating mappings of NRL to target languages
It is system and data format independent
Future proof: it is based on first-order predicate logic, and can be analysed using proof checkers, after suitable translation

What Have You Done With It?

NRL has been used for quite varied integration tasks in financial services:

Trade routing using the NRL constraint language - trades go to a certain route if they pass NRL rules
Reference data mapping: conversion from proprietary bond/equity data hub to an internal XML standards
Corporate action processing: converting from a proprietary vendor feed to an internal format
Several integration projects involving SWIFT messages and their translation

Are there Examples?

The business rules for the Financial Products Markup Language (FpML®) have been published using NRL.

Click here to browse the rules.

We cannot currently provide any public examples of large-scale XML mappings, as they are confidential to our client. Please contact us for further details.

Why not X Instead / How Does NRL Fit in With X?