In terms of simulation and control holonomic constraints are well documented and thus termed
standard. As non-standard constraints, we understand non-holonomic and unilateral constraints. We limit
this survey to mechanical systems with a finite number of degrees of freedom. The long-term behavior of non-
holonomic integrators as compared to structure-preserving integrators for holonomically constrained systems
is briefly discussed. Some recent research regarding the treatment of unilaterally constrained systems by event-
driven or time-stepping schemes for time integration and in the context of optimal control problems is outlined.