19. The system of claim 14 , wherein: one or more of the constraints are specified in the same scope as one or more of corresponding inputs; and the one or more processors are further to insert in-scope imperative code in the computer executable imperative output program representation to enforce the one or more of the constraints.
14. A system for automatic computer translation of input code including constraints to a computer executable imperative output program representation, comprising: one or more processors to: provide an input source program, wherein the input source program is expressed in a programming language that provides for imperative specifications and also provides for declarative specification of constraints, and wherein the input source program includes one or more declaratively specified constraints in accordance with the programming language; translate the input source program to the computer executable imperative output program representation, including to: during compilation-time, automatically generate code comprising constraint representations based at least in part on the one or more declaratively specified constraints, including to automatically generate code comprising one or more corresponding constraint reactor code objects to register input change notification upon instantiation, the one or more corresponding constraint reactor code objects being included in the computer executable imperative output program presentation and having imperative procedures that enforce the declaratively specified constraints; and for at least some of program data members of the input source program, automatically generate corresponding notification code to provide change notification and to accommodate registration for input change notification by constraint representations; and provide the computer executable imperative output program representation as an output; and one or more memories coupled to the one or more processors, configured to provide the one or more processors with instructions.