We have designed, implemented, and proved the correctness of a compiler generator that accepts action semantic descriptions of imperative programming languages. The generated compilers emit absolute code for an abstract RISC machine language that currently is assembled into code for the SPARC and the HP Precision Architecture. Our machine language needs no run-time type-checking and is thus more realistic than those considered in previous compiler proofs. We use solely algebraic specifications; proofs are given in the initial model. 1 Introduction The previous approaches to proving correctness of compilers for non-trivial languages all use target code with run-time type-checking. The following semantic rule is typical for these target languages: (FIRST : C; hv 1 ; v 2 i : S) ! (C; v 1 : S) The rule describes the semantics of an instruction that extracts the first component of the top-element of the stack, provided that the top-element is a pair. If not, then it is implicit that the...

Contents 1 Introduction : : : : : : : : : : : : : : : : : : : : : : : : : : : : 2 2 The expressive power of second order Logic : : : : : : : : : : : 3 2.1 The language of second order logic : : : : : : : : : : : : : 3 2.2 Expressing size : : : : : : : : : : : : : : : : : : : : : : : : 4 2.3 Defining data types : : : : : : : : : : : : : : : : : : : : : 6 2.4 Describing processes : : : : : : : : : : : : : : : : : : : : : 8 2.5 Expressing convergence using second order validity : : : : : : : : : : : : : : : : : : : : : : : : : 9 2.6 Truth definitions: the analytical hierarchy : : : : : : : : 10 2.7 Inductive definitions : : : : : : : : : : : : : : : : : : : : : 13 3 Canonical semantics of higher order logic : : : : : : : : : : : : 15 3.1 Tarskian semantics of second order logic : : : : : : : : : 15 3.2 Function and re

Conventional procedure and type definition mechanisms are not sufficiently powerful to express many programming abstractions that can be captured by syntactic transformations. Unfortunately, conventional macroprocessing is oblivious to the semantics of the base language, resulting in scoping anomalies, poor handling of static semantic errors, and an inability to perform transformations dependent on semantic attributes of the manipulated program. We introduce a new mechanism, semantic macros, which permit such transformations a significant level of access to the static semantic properties of the program fragments they manipulate. In this way, new static semantic processing, including compilation of embedded languages with a rich static semantics of their own, can be incorporated into user-defined language extensions. A proof-of-concept language, XL, is described which embodies this mechanism. Sponsored by the Defense Advanced Research Projects Agency (DoD), monitored by Spac...

We describe the automatic generation of a provably correct compiler for a non-trivial subset of Ada. The compiler is generated from an action semantic description; it emits absolute code for an abstract RISC machine language that currently is assembled into code for the SPARC and the HP Precision Architecture. The generated code is an order of magnitude better than what is produced by compilers generated by the classical systems of Mosses, Paulson, and Wand. The use of action semantics makes the processable language specification easy to read and pleasant to work with. In Proc. ICCL'92, Fourth IEEE International Conference on Computer Languages, pages 117--126. 1 Introduction The purpose of a language designer's workbench, envisioned by Pleban, is to drastically improve the language design process. The major components in such a workbench are: ffl A specification language whose specifications are easily maintainable, and accessible without knowledge of the underlying theory; and f...

Denotational semantics is now used widely for the formal definition of programming languages but there is a lack of appropriate tools to support language development. General purpose language implementation systems are oriented to syntax with poor support for semantics. Specialised denotational semantics based systems correspond closely to the formalism but are rendered inflexible for language experimentation by their monolithic multiple stages Exploratory language development with formal definitions is better served by a unitary notation, encompassing syntax and semantics, which is close to but simpler than denotational semantics. Interactive implementation of the notation then facilitates language investigation through the direct execution of a formal definition as an interpreter for the defined language. This thesis presents Navel, a run-time typed, applicative order, pure functional programming language with integrated context free grammar rules. Navel has been used to develop prot...

Denotational semantics are developed for simple C++ declarations and are implemented in a functional language using a literate programming style. 1 Introduction Computer languages are difficult to learn and understand. Part of the problem is that there is (usually) no formal statement of what various language constructs mean. Denotational semantics [Sch86] provides a formal framework for developing this meaning. Yet there is no denotational semantics for C++. This paper provides a denotational semantics for some simple C++ declarations. 1.1 Audience This paper is intended for a general computer science audience interested in denotational semantics and C++ declarations. A familiarity with C++ and and SML is assumed. Serious students of C++ can see how memory and environments are used. Students of denotational semantics can use this as an example of a semantics of a "real" language. Designers of C++-like languages can use this to guide how new features will work. Finally, C++ impleme...