On the automation-supported derivation of domain-specific UML profiles considering static semantics

In the light of standardization, the model-driven engineering (MDE) is becoming increasingly important for the development of DSLs, in addition to traditional approaches based on grammar formalisms. Metamodels define the abstract syntax and static semantics of a DSL and can be created by using the language concepts of the Meta Object Facility (MOF) or by defining a UML profile.Both metamodels and UML profiles are often provided for standardized DSLs, and the mappings of metamodels to UML profiles are usually specified informally in natural language, which also applies for the static semantics of metamodels and/or UML profiles, which has the disadvantage that ambiguities can occur, and that the static semantics must be manually translated into a machine-processable language.To address these weaknesses, we propose a new automated approach for deriving a UML profile from the metamodel of a DSL. One novelty is that subsetting or redefining metaclass attributes are mapped to stereotype attributes whose values are computed at runtime via automatically created OCL expressions. The automatic transfer of the static semantics of a DSL to a UML profile is a further contribution of our approach. Our DSL Metamodeling and Derivation Toolchain (DSL-MeDeTo) implements all aspects of our proposed approach in Eclipse. This enabled us to successfully apply our approach to the two DSLs Test Description Language (TDL) and Specification and Description Language (SDL).

A focused solution to the avoidance problem

In ML-style module type theory, sealing often leads to situations in which type variables must leave scope, and this creates a need for signatures that avoid such variables. Unfortunately, in general, there is no best signature that avoids a variable, so modules do not always enjoy principal signatures. This observation is called the avoidance problem. In the past, the problem has been circumvented using a variety of devices for moving variables so they can remain in scope. These devices work, but have heretofore lacked a logical foundation. They have also lacked a presentation in which the dynamic semantics is given on the same phrases as the static semantics, which limits their applications. We can provide a best supersignature avoiding a variable by fiat, by adding an existential signature that is the least upper bound of its instances. This idea is old, but a workable metatheory has not previously been worked out. This work resolves the metatheoretic issues using ideas borrowed from focused logic. We show that the new theory results in a type discipline very similar to the aforementioned devices used in prior work. In passing, this gives a type-theoretic justification for the generative stamps used in the early days of the static semantics of ML modules. All the proofs are formalized in Coq.

I Do Not Exist. Problems for Dynamic Semantics

According to dynamic semantics, what is said by an utterance of a sentence is determined by how the common ground is affected by the acceptance of such utterance. It has been claimed that dynamic semantics offers an account of what is said by an utterance in a context that excels that of traditional static semantics. Assertions of negative existential constructions, of the form ‘X does not exist’, are a case in point. These assertions traditionally pose a problem for philosophers of language. A recent proposal, owed to Clapp (2008), argues that static semantics is unable to solve the problem and offers a dynamic semantics account that promises to succeed. In this paper I want to challenge this account and, more generally, the scope of the dynamic semantics framework. I will offer a counterexample, inspired by “answering machine” uses of indexical and demonstrative expressions, to show how dynamic semantics fails. I conclude by considering the merits of both static and dynamic accounts.

Dynamic Pragmatics, Static Semantics

Semantic-pragmatic theorizing took a dynamic turn in the 1970s, but at the time the dynamics remained in the pragmatics and retained a more or less traditional static conception of compositional semantics. Later dynamic semantics built rules for context change into the semantics. This essay argues that the phenomena that motivated the dynamic turn are best explained at the pragmatic level, retaining a notion of propositonal content, and a distinction between content and force. It is argued that while a partial notion of propositional content can be recovered from a dynamic conception of semantic value as context-change potential, some information that plays an important role in the broader explanation of discourse is lost. It is then argued that it is important to retain a notion of speech act force, separated from content.

Expression Compatibility Problem

We solve the Expression Compatibility Problem (ECP) – a variation of the famous Expression Problem (EP) which, in addition to the classical EP concerns, takes into consideration the replacement, refinement, and borrowing of algebraic datatype (ADT) cases. ECP describes ADT cases as components and promotes ideas from Lightweight Family Polymorphism, Class Sharing, and Expression Families Problem. Our solution is based on a formal model for Component-Based Software Engineering that pertains to the Expression Problem. We provide the syntax, static semantics, and dynamic semantics ofour model. We also show that our model can be used to solve the Expression FamiliesProblem as well. Moreover, we show how to embed the model in Scala.

Dynamic Semantics

This article focuses on foundational issues in dynamic and static semantics, specifically on what is conceptually at stake between the dynamic framework and the truth-conditional framework, and consequently what kinds of evidence support each framework. The article examines two questions. First, it explores the consequences of taking the proposition as central semantic notion as characteristic of static semantics, and argues that this is not as limiting in accounting for discourse dynamics as many think. Specifically, it explores what it means for a static semantics to incorporate the notion of context change potential in a dynamic pragmatics and denies that this conception of static semantics requires that all updates to the context be eliminative and distributive. Second, it argues that the central difference between the two frameworks is whether semantics or pragmatics accounts for dynamics, and explores what this means for the oft-heard claim that dynamic semantics blurs the semantics/pragmatics distinction.