This paperlintroduces the reader to many of the salient features of the Cedar programming environment, a state-of-the-art progrmming system that combines in a single integrated environment: high quality graphics, a sophisticated editor and document preparation facility, and a variety of tools for the programmer to use in the construction and debugging of his programs. The Cedar programming language [8] is a strongly typed, compiler-oriented language of the Pascal family. What is especially interesting about the Cedar project is that it is one of the few examples where an interactive, experimental programming environment has been built for this kind of language. In the past, such environments have been confined to dynamically typed languages like Lisp and Smalltalk.

Clisp is an attempt to make Lisp programs easier to read and write by extending the syntax of Lisp to include infix operators, IF-THEN statements, FOR-DO-WHILE statements, and similar Algol-like constructs, without changing the structure or representation of the language. Clisp is implemented through Lisp's error handling machinery, rather than by modifying the interpreter. When an expression is encountered whose evaluation causes an error, the expression is scanned for possible Clisp constructs, which are then converted to the equivalent Lisp expressions. Thus, users can freely intermix Lisp and Clisp without ut having to distinguish which is which. Emphasis in the design and development of Clisp has been on the system aspects of such a facility, with the goal of producing a useful tool, not just another language. To this end, Clisp includes interactive error correction and many "do-what-I-mean" features.