design-by-contract

I read that compiler can enforce dbc at compile time.. How does it do it? As far as I know, the most powerful static DbC language so far is Spec# by Microsoft Research . It uses a powerful static analysis tool called Boogie which in turn uses a powerful Theorem Prover / Constraint Solver called Z3 to prove either the fulfillment or violation of contracts at design time. If the Theorem Prover can prove that a contract will always be violated, that's a compile error. If the Theorem Prover can prove that a contract will never be violated, that's an optimization: the contract checks are removed

There are several questions on StackOverflow discussing the question of when one should use an assert statement versus throwing some exception. (Examples here , here , here , here , and here . However, I have come to suspect that the conventional wisdom of assert-versus-throw is based upon the assumption that you are running within a JVM. In the GWT universe, where your Java gets transliterated to JavaScript and runs in the context of a browser, the set of tradeoffs feels different: asserts are always compiled-away when running in a browser, and anything that keeps the size of your JavaScript

Consider this immutable type: public class Settings { public string Path { get; private set; } [ContractInvariantMethod] private void ObjectInvariants() { Contract.Invariant(Path != null); } public Settings(string path) { Contract.Requires(path != null); Path = path; } } Two things to notice here: There is a contract invariant which ensures the Path property can never be null The constructor checks the path argument value to respect the previous contract invariant At this point, a Setting instance can never have a null Path property. Now, look at this type: public class Program { private

I was reading about contracts in Thoughts about C++17 by B. Stroustrup and assisted a small presentation talking about them but I am not sure I have understood them really. So I have a some interrogations and if it is possible to illustrate them with some examples : Are contracts just a better replacement of the classic assert() and should they be used together ? What contracts really are put in simple terms for a software dev ? Would contracts have an impact on how we handle exceptions ? If yes, how should we use exceptions and contracts ? Would using contracts imply an overhead at execution

I have been trying to figure out the best practices to write test-friendly code, but more specifically the practices related to object construction. In the blue book we discovered that we should enforce invariants when creating objects to avoid the corruption of our entities, value objects, etc. with this thought in mind, Design By Contract seems like the solution to avoid the corruption of our objects, but when we follow this, we could end up writing code like this: class Car { //Constructor public Car(Door door, Engine engine, Wheel wheel) { Contract.Requires(door).IsNotNull("Door is