This is a stand-alone help system that can be used instead of Dyalog APL's single page on Regular Expressions the interpreter comes with.
Providing such a massive amount of information on a single page makes it difficult to use. Splitting it into several pages, providing a tree structure, offering a powerful search feature and a proper index makes life significantly easier when it comes to Regular Expressions.
In addition the help system also includes the "PCRE Syntax summary" which is coming as a separate document in a standard Dyalog implementation.
