Module variables 

Contains the variables which are used by the [Solver].

A variable, in the context of the solver, is a view onto a domain. It may forward domain information unaltered, or apply transformations which can be performed without the need of constraints.

We define 2 types of variables:

• Integer Variables (IntegerVariable) - These are represented by DomainIds when interacting with the [Solver]. These variables can be created using [Solver::new_bounded_integer] when creating a variable with the domain between a lower-bound and an upper-bound or using [Solver::new_sparse_integer] when creating a variable with holes in the domain. These variables can be transformed (according to the trait TransformableVariable) to create an AffineView.
• Literals (Literal) - These specify booleans that can be used when interacting with the [Solver]. A Literal can be created using [Solver::new_literal].

Structs

AffineView

Models the constraint y = ax + b, by expressing the domain of y as a transformation of the domain of x.

DomainId

A structure which represents the most basic IntegerVariable; it is simply the id which links to a domain (hence the name).

Literal

Traits

IntegerVariable

A trait specifying the required behaviour of an integer variable such as retrieving a lower-bound (IntegerVariable::lower_bound).

TransformableVariable

Trait for transforming a variable.