Interlisp

Interlisp is an early programming language and integrated development environment (IDE) developed in the late 1960s at Xerox PARC (Palo Alto Research Center). It is a dialect of the Lisp programming language designed to support interactive and exploratory programming, especially in the context of artificial intelligence research.

Interlisp distinguished itself by combining a powerful Lisp compiler with an extensive set of debugging, editing, and visualization tools. Its environment included a sophisticated user interface with windows, menus, and a command language, making it one of the first systems to provide an integrated, user-friendly programming workspace. This environment facilitated rapid prototyping and complex debugging tasks, significantly influencing future IDE designs.

The language featured advanced memory management techniques, incremental compilation, and a flexible macro system, which allowed users to extend and customize the environment. Interlisp's design emphasized ease of use and interactivity, with a focus on supporting high-level abstractions and dynamic programming styles characteristic of Lisp.

Interlisp was used extensively during the 1970s and early 1980s for AI and computer science research. It ran on various hardware platforms, including Xerox's Xerox 1108 and later on other systems such as DEC VAX and Sun workstations. Despite its discontinuation in the late 1980s, Interlisp's influence persisted, notably in the development of later integrated programming environments and in efforts to make programming more accessible.

Today, Interlisp remains a notable milestone in the history of programming languages and IDEs, recognized for its innovative approach to interactive programming and environment integration that prefigured many features common in modern software development tools.