The thesis describes the requirement, design, and implementation of a software package that can be used to perform quantitative studies on certain aspects of a programming task. Of specific interest are experiments with the level of interactiveness of the human-computer interface relating to program construction and with language design principles relating to identifier scope rules. The software package for conducting these experiments is an interactive language environment called PEEP. Its base language is Pascal and its design is based on Johnston's semantic models of computation. Storage representations and implementation of these semantic models are described. These models depicting the compile-time structure, run-time structure, and realization of the static and the dynamic scoping rules. The evolution and current research of programming environments, user interface to PEEP, and future research on PEEP are also focuses of attention. / Master of Science