/// <summary>
/// Gets a new specification function which corresponds to the logical
/// combination of the specified objects: <c>AND</c>.
/// </summary>
/// <returns>A specification function.</returns>
/// <param name="spec">A specification function.</param>
/// <param name="composeWith">A specification expression.</param>
/// <typeparam name="T">The generic type of the specifications.</typeparam>
public static ISpecificationFunction <T> And <T>(this ISpecificationFunction <T> spec, ISpecificationExpression <T> composeWith)
{
var func1 = GetFunction(spec);
var func2 = composeWith.GetFunction();
return(Spec.Func <T>(o => func1(o) && func2(o)));
}
/// <summary>
/// Gets a new specification function which corresponds to the logical
/// alternation of the specified objects: <c>OR</c>.
/// </summary>
/// <returns>A specification function.</returns>
/// <param name="spec">A specification function.</param>
/// <param name="composeWith">Another specification function.</param>
/// <typeparam name="T">The generic type of the specifications.</typeparam>
public static ISpecificationFunction <T> Or <T>(this ISpecificationFunction <T> spec, ISpecificationFunction <T> composeWith)
{
var func1 = GetFunction(spec);
var func2 = GetFunction(composeWith);
return(Spec.Func <T>(o => func1(o) || func2(o)));
}
/// <summary>
/// Transforms the specification to a target type, using a selector function.
/// </summary>
/// <returns>The transformed specification function.</returns>
/// <param name="selector">A selector to specify how an instance of the transformed/target type may be used to get an instance of the originally-specified type.</param>
/// <typeparam name="TTarget">The target type.</typeparam>
public ISpecificationFunction <TTarget> To <TTarget>(Func <TTarget, TOrigin> selector)
{
if (selector == null)
{
throw new ArgumentNullException(nameof(selector));
}
var func = spec.GetFunction();
Func <TTarget, bool> transformed = target => func(selector(target));
return(Spec.Func(transformed));
}
/// <summary>
/// Gets a new specification function which corresponds to the logical
/// negation of the specified object: <c>NOT</c>.
/// </summary>
/// <returns>A specification function.</returns>
/// <param name="spec">A specification function.</param>
/// <typeparam name="T">The generic type of the specification.</typeparam>
public static ISpecificationFunction <T> Not <T>(this ISpecificationFunction <T> spec)
{
var func = GetFunction(spec);
return(Spec.Func <T>(o => !func(o)));
}
/// <summary>
/// Gets a specification function which copies the specified specification expression.
/// </summary>
/// <returns>A specification function.</returns>
/// <param name="spec">A specification expression.</param>
/// <typeparam name="T">The generic type of the specification.</typeparam>
public static ISpecificationFunction <T> AsSpecificationFunction <T>(this ISpecificationExpression <T> spec)
{
return(Spec.Func(spec.GetFunction()));
}
