Roger Costello has announced a tool which, given a value range, will generate the corresponding regular expression for W3C XML Schema.

W3C XML Schema provides a simpler way to constrain numeric datatypes into ranges through "maxInclusive" and "minExclusive" facets; however there are circumstances where one needs to use regular expressions instead (on non-numeric datatypes such as unions, or to define numeric datatypes that can belong to unions of ranges, for instance).

Although not directly related to XML technologies, the regular expressions generated by this tool or the simple algorithm described in the package may therefore be of help when writing W3C XML Schemas.

This tool is written in Java and available for download under the GPL open source license.