High-level programming language

Abstract: Various embodiments are described for searching and retrieving documents based on a natural language input. A computer-implemented natural language processor electronically receives a natural language input phrase from an interface device. The natural language processor attributes a concept to the phrase with the natural language processor. The natural language processor searches a database for a set of documents to identify one or more documents associated with the attributed concept to be included in a response to the natural language input phrase. The natural language processor maintains the concepts during an interactive session with the natural language processor. The natural language processor resolves ambiguous input patterns in the natural language input phrase with the natural language processor. The natural language processor includes a processor, a memory and/or storage component, and an input/output device.

Abstract: We present a tentative theory of programming language expressiveness based on reductions (language translations) that preserve observational equivalence These are called “abstraction-preserving” because of a connection with a definition of “abstraction” or “information-hiding” mechanism If there is an abstraction-preserving reduction from one language to another, then essentially every function on natural numbers that is definable in the first is also definable in the second Moreover, regardless of the set of first-order functions definable in either language, no programming language with an abstraction mechanism can be reduced to a language without Since Lisp with user-defined special forms does not have an abstraction mechanism, it is therefore not “universal” in this theory, in spite of the ability to define every partial recursive function on the natural numbers Several examples and counter-examples to abstraction-preserving reductions are given We do not know whether there is a natural universal language with respect to abstraction-preserving reduction

Abstract: Higher-order assembly language (HOAL) generalizes combinator-based target languages by allowing free variables in terms to play the role of registers. We introduce a machine model for which HOAL is the assembly language, and prove the correctness of a compiler from a tiny language into HOAL. We introduce the notion of a λ-representation, which is an abstract binding operation, show how some common representations of procedures and continuations can be expressed as λ-representations. Last, we prove the correctness of a typical procedure-calling convention in this framework.