Abstract: A method and system for computer programming provides a graphical editor function for creation and editing of a computer program by manipulation of graphical images on a high-resolution display. The program is specified in terms of a definition language which can be executed by a simulation function. This function simulates execution of the program on a different, target processor as if the program were expressed in a different language which can be executed by the target processor; in addition the simulation function incorporates a simulation of the external environment of the target processor and of the interaction of the program with that environment. The graphical display of the program is animated during execution so that the user can observe and check the program's operation. When the simulated execution is satisfactory the definition-language version of the program is tanslated into the language executable on the target processor.