stringbrewer: Generate random strings matching a pattern.

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.

This is best understood by example. The pattern below generates Telugu morphemes::

# Generate random Telugu-like morphemes
(Base HalantGroup{0,2} TopPositionedVowel?){1,3}

Base = క-న,ప-హ
Halant = 0C4D
HalantGroup = Halant Base
TopPositionedVowel = 0C46-0C48,0C4A-0C4C

The first line is a comment; the second is the recipe, and the blank line denotes the beginning of the ingredients list. Let's look at the ingredients. A Base is any character either in the range 0x0C15-0C28 or 0C2A-0C39. (We specified these as literals, just because we could). A Halant is the character 0x0C4D. A HalantGroup is a halant followed by a base.

Now you understand the ingredients, the recipe is simple to understand if you think in terms of regular expression syntax: a base followed by zero, one or two halant groups, plus an optional top-positioned vowel, all repeated between one and three times.

__init__

 | __init__(from_string=None, from_file=None, recipe=None, ingredients=None)

Initializes a StringBrewer object

You must provide either a file name, a string, or a recipe string and ingredients dictionary.

Arguments:

• from_file - A file name of a file containing a pattern.
• from_string - A pattern in a string.
• recipe - The recipe part of a pattern.
• ingredients - A dictionary of regular expressions.

generate_all

 | generate_all()

Generates a list of all combinations.

If there are more than 100,000 combinations, an exception is raised to avoid running out of memory.

generate

 | generate(min_length=0, max_length=None)

Generates a single random combination.

Arguments:

• min_length - Minimum length (zero if not specified)
• max_length - Maximum length (no maximum if not specified)