scholarly journals Categorical model of structural operational semantics for imperative language

2016 ◽  
Vol 40 (2) ◽  
pp. 203-219 ◽  
Author(s):  
William Steingartner ◽  
Valerie Novitzká
Keyword(s):  
Programming Languages ◽  
Operational Semantics ◽  
Mathematical Structure ◽  
Program Behavior ◽  
Elementary Steps ◽  
Categorical Model ◽  
Structural Operational Semantics ◽  
State Changes ◽  
Definition Of ◽  
Graphical Illustration

Definition of programming languages consists of the formal definition of syntax and semantics. One of the most popular semantic methods used in various stages of software engineering is structural operational semantics. It describes program behavior in the form of state changes after execution of elementary steps of program. This feature makes structural operational semantics useful for implementation of programming languages and also for verification purposes. In our paper we present a new approach to structural operational semantics. We model behavior of programs in category of states, where objects are states, an abstraction of computer memory and morphisms model state changes, execution of a program in elementary steps. The advantage of using categorical model is its exact mathematical structure with many useful proved properties and its graphical illustration of program behavior as a path, i.e. a composition of morphisms. Our approach is able to accentuate dynamics of structural operational semantics. For simplicity, we assume that data are intuitively typed. Visualization and facility of our model is not only a new model of structural operational semantics of imperative programming languages but it can also serve for education purposes.

scholarly journals Structural Operational Semantics

1999 ◽  
Vol 6 (30) ◽  
Author(s):  
Luca Aceto ◽  
Willem Jan Fokkink ◽  
Chris Verhoef
Keyword(s):  
Programming Languages ◽  
Operational Semantics ◽  
The Sixties ◽  
Structural Operational Semantics ◽  
High Level

The importance of giving precise semantics to programming and specification<br />languages was recognized since the sixties with the development of the<br />first high-level programming languages (cf. e.g. [30, 206] for some early accounts).<br />The use of operational semantics - i.e. of a semantics that explicitly<br />describes how programs compute in stepwise fashion, and the possible<br />state-transformations they perform - was already advocated by McCarthy<br />in [147], and elaborated upon in references like [142, 143]. Examples of full-blown<br />languages that have been endowed with an operational semantics are<br />Algol 60 [140], PL/I [173], and CSP [178].

A formalism for the specification of essentially-algebraic structures in 2-categories

1992 ◽  
Vol 2 (1) ◽  
pp. 1-28 ◽  
Author(s):  
A. J. Power ◽  
Charles Wells
Keyword(s):  
Programming Languages ◽  
Functional Programming ◽  
Operational Semantics ◽  
Higher Order ◽  
Two Dimensional ◽  
Functional Programming Languages ◽  
One Dimensional ◽  
Special Cases ◽  
Rewrite Rules ◽  
Definition Of

A type of higher-order two-dimensional sketch is defined which has models in suitable 2-categories. It has as special cases the ordinary sketches of Ehresmann and certain previously defined generalizations of one-dimensional sketches. These sketches allow the specification of constructions in 2-categories such as weighted limits, as well as higher-order constructions such as exponential objects and subobject classifiers, that cannot be sketched by limits and colimits. These sketches are designed to be the basis of a category-based methodology for the description of functional programming languages, complete with rewrite rules giving the operational semantics, that is independent of the usual specification methods based on formal languages and symbolic logic. A definition of ‘path grammar’, generalizing the usual notion of grammar, is given as a step towards this goal.

scholarly journals A Modular SOS for Action Notation

1999 ◽  
Vol 6 (56) ◽  
Author(s):  
Peter D. Mosses
Keyword(s):  
Programming Languages ◽  
Operational Semantics ◽  
Denotational Semantics ◽  
Specification Language ◽  
Algebraic Specification ◽  
Recent Proposal ◽  
Structural Operational Semantics ◽  
The Common ◽  
Basic Concepts ◽  
Pragmatic Aspect

Modularity is an important pragmatic aspect of semantic<br />descriptions: good modularity is needed to allow the reuse of existing descriptions when extending or changing the described language. In denotational semantics, the issue of modularity has received much attention, and appropriate abstractions have been introduced, so that definitions of semantic functions may be independent of the details of how computations are modeled. In structural operational semantics (SOS), however, this issue has largely been neglected, and SOS descriptions of programming languages typically exhibit rather poor modularity; the original SOS given for Action Notation (the notation for the semantic entities used in action semantics) suffered from the same problem.<br />This paper recalls a recent proposal, called MSOS, for obtaining a high<br />degree of modularity in SOS, and presents an MSOS description of Action<br />Notation. Due to its modularity, the MSOS description pinpoints some<br />complications in the design of Action Notation, and should facilitate the<br />design of an improved version of the notation. It also provides a major<br />example of the applicability of the MSOS framework.<br />The reader is assumed to be familiar with conventional SOS and with<br />the basic concepts and constructs of Action Notation. The description<br />of Action Notation is formulated almost entirely in Casl, the common<br />algebraic specification language.

scholarly journals From CML to process Algebras

1993 ◽  
Vol 22 (433) ◽  
Author(s):  
Flemming Nielson ◽  
Hanne Riis Nielson
Keyword(s):  
Programming Languages ◽  
Programming Language ◽  
Process Algebra ◽  
Operational Semantics ◽  
Concurrent Programming ◽  
Process Algebras ◽  
Standard Ml ◽  
Concurrent Programming Languages ◽  
Structural Operational Semantics ◽  
Communication Behaviours

<p>Reppy's language CML extends Standard ML of Milner et al. with primitives for communication. It thus inherits a notion of strong polymorphic typing and may be equipped with a structural operational semantics. We formulate an effect system for statically expressing the communication behaviours of CML programs as these are not otherwise reflected in the types.</p><p>We then show how types and behaviours evolve in the course of computation: types may decrease and behaviours may loose alternatives as well as decrease. It will turn out that the syntax of behaviours is rather similar to that of a process algebra; our main results may therefore be viewed as regarding the semantics of a process algebra as an <em>abstraction</em> of the semantics of an underlying programming language. This establishes a new kind of connection between ''realistic'' concurrent programming languages and ''theoretical'' process algebras.</p>

scholarly journals Reasoning about “reasoning about reasoning”: semantics and contextual equivalence for probabilistic programs with nested queries and recursion

2022 ◽  
Vol 6 (POPL) ◽  
pp. 1-28
Author(s):  
Yizhou Zhang ◽  
Nada Amin
Keyword(s):  
Programming Languages ◽  
Formal Semantics ◽  
Operational Semantics ◽  
Relational Reasoning ◽  
Linguistic Feature ◽  
Technical Developments ◽  
Contextual Equivalence ◽  
Nested Queries ◽  
Definition Of ◽  
Probabilistic Programs

Metareasoning can be achieved in probabilistic programming languages (PPLs) using agent models that recursively nest inference queries inside inference queries. However, the semantics of this powerful, reflection-like language feature has defied an operational treatment, much less reasoning principles for contextual equivalence. We give formal semantics to a core PPL with continuous distributions, scoring, general recursion, and nested queries. Unlike prior work, the presence of nested queries and general recursion makes it impossible to stratify the definition of a sampling-based operational semantics and that of a measure-theoretic semantics—the two semantics must be defined mutually recursively. A key yet challenging property we establish is that probabilistic programs have well-defined meanings: limits exist for the step-indexed measures they induce. Beyond a semantics, we offer relational reasoning principles for probabilistic programs making nested queries. We construct a step-indexed, biorthogonal logical-relations model. A soundness theorem establishes that logical relatedness implies contextual equivalence. We demonstrate the usefulness of the reasoning principles by proving novel equivalences of practical relevance—in particular, game-playing and decisionmaking agents. We mechanize our technical developments leading to the soundness proof using the Coq proof assistant. Nested queries are an important yet theoretically underdeveloped linguistic feature in PPLs; we are first to give them semantics in the presence of general recursion and to provide them with sound reasoning principles for contextual equivalence.

scholarly journals Exploiting Labels in Structural Operational Semantics

2005 ◽  
Vol 12 (8) ◽  
Author(s):  
Peter D. Mosses
Keyword(s):  
Programming Languages ◽  
Operational Semantics ◽  
Concurrent Systems ◽  
Sequential Programming ◽  
Structural Operational Semantics ◽  
Full Power

Structural Operational Semantics (SOS) allows transitions to be labelled. This is fully exploited in SOS descriptions of concurrent systems, but usually not at all in conventional descriptions of sequential programming languages.<br /> <br />This paper shows how the use of labels can provide significantly simpler and more modular descriptions of programming languages. However, the full power of labels is obtained only when the set of labels is made into a category, as in the recently-proposed MSOS variant of SOS.

scholarly journals On the Action Semantics of Concurrent Programming Languages

1992 ◽  
Vol 21 (424) ◽  
Author(s):  
Peter D. Mosses
Keyword(s):  
Programming Languages ◽  
Operational Semantics ◽  
Denotational Semantics ◽  
Semantic Description ◽  
Paper Briefly ◽  
Action Semantics ◽  
Concurrent Programming Languages ◽  
Structural Operational Semantics ◽  
Bisimulation Equivalence ◽  
Basic Concepts

<p>Action semantics is a framework for semantic description of prograrnming languages. In this framework, actions are semantic entities, used to represent the potential behaviour of programs --- also the contributions that parts of programs make to such behaviour. The notation for expressing actions, called action notation, is combinator-based. It is used in much the same way that lambda-notation is used in denotational semantics. However, the essence of action notation is operational, rather than mathematical, and its meaning is formally defined by a structural operational semantics together with a bisimulation equivalence.</p><p>This paper briefly motivates action semantics, and explains the basic concepts. It then illustrates the use of the framework by giving an action semantic description of a small example language. This language includes a simple form of concurrency: tasks that may synchronize by means of rendezvous. The paper also discusses the operational semantics of action notation, focusing on the primitive actions that represent asynchronous message transmission and process initiation.</p>

scholarly journals Towards language-to-language transformation

2021 ◽  
Author(s):  
Dawid Kopetzki ◽  
Michael Lybecait ◽  
Stefan Naujokat ◽  
Bernhard Steffen
Keyword(s):  
Operational Semantics ◽  
General Purpose ◽  
Educational Setting ◽  
Control Data ◽  
Structural Rules ◽  
Language Transformation ◽  
Structural Operational Semantics ◽  
Definition Of ◽  
Rule Systems ◽  
Matching Concept

AbstractThis paper proposes a simplicity-oriented approach and framework for language-to-language transformation of, in particular, graphical languages. Key to simplicity is the decomposition of the transformation specification into sub-rule systems that separately specify purpose-specific aspects. We illustrate this approach by employing a variation of Plotkin’s Structural Operational Semantics (SOS) for pattern-based transformations of typed graphs in order to address the aspect ‘computation’ in a graph rewriting fashion. Key to our approach are two generalizations of Plotkin’s structural rules: the use of graph patterns as the matching concept in the rules, and the introduction of node and edge types. Types do not only allow one to easily distinguish between different kinds of dependencies, like control, data, and priority, but may also be used to define a hierarchical layering structure. The resulting Type-based Structural Operational Semantics (TSOS) supports a well-structured and intuitive specification and realization of semantically involved language-to-language transformations adequate for the generation of purpose-specific views or input formats for certain tools, like, e.g., model checkers. A comparison with the general-purpose transformation frameworks ATL and Groove, illustrates along the educational setting of our graphical WebStory language that TSOS provides quite a flexible format for the definition of a family of purpose-specific transformation languages that are easy to use and come with clear guarantees.

scholarly journals Persistent Stochastic Non-Interference

2021 ◽  
Vol 181 (1) ◽  
pp. 1-35
Author(s):  
Jane Hillston ◽  
Andrea Marin ◽  
Carla Piazza ◽  
Sabina Rossi
Keyword(s):  
Process Algebra ◽  
Operational Semantics ◽  
Evaluation Process ◽  
Decision Algorithm ◽  
Secure Systems ◽  
Information Flow Security ◽  
Structural Operational Semantics ◽  
Timing Properties ◽  
Functional Point ◽  
Security Property

In this paper, we study an information flow security property for systems specified as terms of a quantitative Markovian process algebra, namely the Performance Evaluation Process Algebra (PEPA). We propose a quantitative extension of the Non-Interference property used to secure systems from the functional point view by assuming that the observers are able to measure also the timing properties of the system, e.g., the response time of certain actions or its throughput. We introduce the notion of Persistent Stochastic Non-Interference (PSNI) based on the idea that every state reachable by a process satisfies a basic Stochastic Non-Interference (SNI) property. The structural operational semantics of PEPA allows us to give two characterizations of PSNI: one based on a bisimulation-like equivalence relation inducing a lumping on the underlying Markov chain, and another one based on unwinding conditions which demand properties of individual actions. These two different characterizations naturally lead to efficient methods for the verification and construction of secure systems. A decision algorithm for PSNI is presented and an application of PSNI to a queueing system is discussed.

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