myPatterns tutorial

overview

myPatterns is a flexible library for pattern matching in Java and JavaScript programs.

Pattern matching is a well-known programming mechanism for recognizing data having a particular shape (or "matching" a particular "pattern"), and at the same time binding some variables occurring in the pattern to some sub-structures of those instances.

The standard matching implementations included in Java and in JavaScript are limited to pattern matching of strings using regular expressions. Regexps are a very powerful matching notation, directly built into the JavaScript language, and implemented in Java by the standard library java.util.regex.

MyPatterns implements an even more general form of pattern matching:

by allowing to match data structures of any kind besides strings: numbers, arrays, hashtables, objects, and so on, using a predefined notation (an extended form of JSON for matching objects including regexps for matching strings)
by offering, beyond the predefined notation, the liberty to override it with custom notations for any data types

Indeed, text matching is extremely useful when isolating substrings of "flat" strings, but cannot cope with data containing structures nested to an arbitrary level. Such "recursively" structured data are much better handled by the kind of matching that myPatterns implements.

chapters

Next: Predefined notation