DELISA(ID:3981/del007)for Delaware Extensible Lisp in the Style of APL Extensible Lisp 1.5 developed at University of Delaware 1972-3, featuring the ability to remap nealry all symbols. Related languages
References: To develop a complete set of primitive operators which pernit the description of current programming languages' environments as well as the description of arbitrary environment structures. Current status - A set of primitive operators have been defined which describe static, lexical, and dynamic environments. These operators arc currently being implemented and exercised. External link: Online copy Extract: General Approach General Approach: At the University of Delaware a language system called DELISA is implemented as an interpreter, written in Burroughs Extended ALGOL for the B56700. The language is a semantic super-set of LISP 1.5; it provides symbolic and numeric manipulation, and arbitrary digraphs and tree data structures. The language was implemented to satisfy teaching and research goals. The environment of the language is dynamic, that is, the binding of a symbol to its value is in some sense the most delayed possible. When a symbol is evaluated, a reference is made to the latest dynamic level for that symbol. A reference on a symbol produced the value assigned by the last assignment to that variable, no matter in what dynamic level the assignment occurred. The DELISA system is extensible, providing convenient high-level operator definition and syntax extensions within the language as well as relatively convenient low-level primitive operator extensions. The environment, all data structures and activation records for function calls, are list structures and are capable of being referenced and manipulated as any other list structure. We have proposed a small set of primitive operators which will give the user controlled binding of a symbol to an arbitrary dynamic level. These primitives modify the value storage mechanism so that the implicit reference mechanism in the interpreter, invoked by symbol evaluation, produces the desired reference. These primitives permit the evaluation of expressions in DELISA in the context of static, lexicographic, and dynamic environments. They also provide name (or quoted) parameter passing in DELISA in which the S-expression is correctly evaluated in the context of the caller's environment. It remains to be shown that these primitives are complete, permitting the description of current programming languages' environments as well as arbitrary environment structures. in SIGPLAN Notices 8(06) June 1973 SPECIAL ISSUE: Abstracts in programming language-related research view details in SIGPLAN Notices 8(06) June 1973 SPECIAL ISSUE: Abstracts in programming language-related research view details in SIGPLAN Notices 8(06) June 1973 SPECIAL ISSUE: Abstracts in programming language-related research view details in SIGPLAN Notices 8(06) June 1973 SPECIAL ISSUE: Abstracts in programming language-related research view details Resources
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