Xeger

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Xeger generates strings that match a regex-like pattern.

Think: regex → strings.

This library focuses on a generatable subset of regex syntax (no backrefs/lookarounds).

Hex.pm Documentation License

Installation

def deps do
  [
    {:xeger, "~> 0.1.0"}
  ]
end

Quick example

Xeger.take("a(b|c){2}\\d", 10)
#=> ["abb0", "abb1", ...]

Xeger.random("a(b|c){2}\\d")
#=> "acb5" -- one random match, not the whole set; output varies each call

Xeger.stream("a*")
|> Enum.take(10)
#=> ["", "a", "aa", "aaa", "aaaa", "aaaaa", "aaaaaa", "aaaaaaa", "aaaaaaaa", "aaaaaaaaa"]
# unbounded quantifiers are infinite by default -- stream/2 is lazy either way

# Or use the ~X sigil for a more idiomatic API
~X/a(b|c){2}\d/
#=> "abc9" -- same as Xeger.random/1; add /c or /s for compile/stream instead

Options

  • :max_repeat - caps *, +, {m,} at this many repeats (default: none -- unbounded)
  • :alphabet - codepoints used for . and negated classes (default: printable ASCII)
  • :seed - makes Xeger.random/2's output reproducible (default: none -- fresh randomness each call)

Documentation

Full API docs: hexdocs.pm/xeger.

License

MIT