A language-independent programmer's interface

This paper addresses the general problem of creating a suitable on-line environment for programming. The amount of software, and the effort required to produce it, to support such an on-line environment is very large relative to that needed to produce a programming language, and is largely responsible for the scarcity of such programming environments. The size of this effort was largely responsible for the scrapping of a major language (QA4) as a separate entity and its inclusion instead as a set of extensions in a LISP environment. The few systems which do exist (e.g., LISP, APL, BASIC, and PL/I) have greatly benefited their users and have strongly contributed to the widespread acceptance of the associated language.