5.7 Exceptions and conditions

Scheme allows programs to deal with exceptional situations using two cooperating facilities: The exception system for raising and handling exceptional situations, and the condition system for describing these situations.

The exception system allows the program, when it detects an exceptional situation, to pass control to an exception handler, and to dynamically establish such exception handlers. Exception handlers are always invoked with an object describing the exceptional situation. Scheme’s condition system provides a standardized taxonomy of such descriptive objects, as well as a facility for extending the taxonomy.