VISIBLE PASCAL PROGRAMMING.

Abstract

A new mode of programming that uses an interactive direct-execution system of Pascal is presented. The innovation is that the programmer at the terminal is permitted maximum interaction for program execution, debugging and testing, all at source level. Syntax and semantic errors are flagged and displayed on the terminal as the programmer types in a wrong token. Correction can be made on the spot without interrupting the whole process. Furthermore, a set of interactive commands is incorporated in the system for checking logical errors, making corrections and changing values for variables, and then resuming program execution. Moreover, during execution the internal data structures can be displayed as 'execution snapshots. ' By observing these snapshots, the programmer can have a better understanding of how the program is being executed.