Module combinator 

A unique feature of unsynn is that one can define a parser as a composition of other parsers on the fly without the need to define custom structures. This is done by using the Cons and Either types. The Cons type is used to define a parser that is a conjunction of two to four other parsers, while the Either type is used to define a parser that is a disjunction of two to four other parsers.

Structs

Cons

Conjunctive A followed by B and optional C and D When C and D are not used, they are set to Nothing.

Enums

Either

Disjunctive A or B or optional C or D tried in that order. When C and D are not used, they are set to Invalid.