Parse a string into a Dependency object.

*/.

Arch models an architecture dependency restriction, commonly used to restrict the relation to one some architectures.

A Dependency is the top level type that models a full Dependency relation.

Possibility models a concrete Possibility that may be satisfied in order to satisfy the Dependency Relation.

A Relation is a set of Possibilities that must be satisfied.

VersionRelation models a version restriction on a possibility, such as greater than version 1.0, or less than 2.0.