RegularLanguage

Alt(left, right) represents the union of two regular languages. We call it "Alt" for consistency with the names used in the "Parsing With Derivatives" paper.

AnyStringToken represents the set of all strings. For tab completion purposes, this is used to represent the name of the executable. (It may be aliased or renamed to be different than Command.Single.name.)

Cat(left, right) represents the concatenation of two regular languages.

The Empty language (∅) accepts no strings.

The Epsilon language (ε) accepts only the empty string.

Permutation is like Cat, but it is a commutative monoid. A Permutation(a_1, a_2, ..., a_{k}) is equivalent to the following language:

a2 ~ Permutation(a_1, a_3, ..., a_k) | a1 ~ Permutation(a_2, a_3, ..., a_k) | ... ak ~ Permutation(a_1, a_2, ..., a_{k - 1})

So when we calculate its derivative, we apply the above "desugaring" transformation, then compute the derivative as usual.

A PrimTypeToken(value) language represents the regular language containing any strings s where value.validate(s) succeeds.

Rep(language, min, max) represents the repetition of language. The number of repetitions can be bounded via min and max. Setting max=None represents the "Kleene star" of language.

A StringToken(value) language represents the regular language that contains only value.

The names of the product elements

The name of the type