ComposingSpecifications

Specification objects may be logically composed/combined. There are three operators to do this: And, Or and Not. They are demonstrated by the following examples. Note that for brevity these examples use dynamic specification expressions. Composition works identically with instances of specification classes.

// And
var overSix = Spec.Expr<int>(x => x > 6);
var underTen = Spec.Expr<int>(x => x < 10);
var sevenEightNine = overSix.And(underTen);

// Or
var overSix = Spec.Expr<int>(x => x > 6);
var underTwo = Spec.Expr<int>(x => x < 2);
var notTwoToSix = overSix.Or(underTwo);

// Not
var overSix = Spec.Expr<int>(x => x > 6);
var sixOrLess = overSix.Not();

• Composing two specification expressions, or using Not with an expression, will create a new specification expression
• Composing two specification functions, or a combination of an expression and a function, or using Not with a function will create a new specification function