Patterns are specified in the StringBrewer pattern language, and are made up of
two parts: a recipe and a set of ingredients. A recipe is essentially a modified
form of regular expression; whitespace is not significant, and each ingredient
name is replaced by its definition. An ingredient is a space-separated list of
items; each item is either a character (specified either as a literal character
or as a Unicode codepoint in hexadecimal), a range of characters separated by
hyphens, or a union of items separated by commas. Ingredients may also contain
references to other ingredients.