CSP Types

type
    Variable[T] = ref object
        ## Represents a Node in the CSP Graph
        name: string
            ## Unique name of the Variable
            ## TODO: Currently user-enforced
        domain: seq[T]
            ## Domain of the variable as a
            ## finite, ordered set
        value: T
            ## Current value of the variable,
            ## used to represent an assignment

    Constraint*[T] = ref object
        ## A function that subsets valid combinations
        ## of values for its variables. Represents
        ## an Arc or Multi-Arc in the CSP Graph
        variables: seq[Variable[T]]
            ## The list of Variable objects checked
        predicate: proc(x: varargs[T]): bool
            ## The function computing satisfaction

    Problem*[T] = ref object
        ## A CSP Graph with well-defined solving algorithms
        variables: TableRef[string, Variable[T]]
            ## Links the Names of Nodes to their Reference
        constraints: TableRef[string, seq[Constraint[T]]]
            ## Links the Names of Nodes to their Constraints