Event-driven Adaptation in COP

Context-Oriented Programming languages provide us with primitive constructs to adapt program behaviour depending on the evolution of their operational environment, namely the context. In previous work we proposed ML_CoDa, a context-oriented language with two-components: a declarative constituent for programming the context and a functional one for computing. This paper describes an extension of ML_CoDa to deal with adaptation to unpredictable context changes notified by asynchronous events.Comment: In Proceedings PLACES 2016, arXiv:1606.0540

A generic operational metatheory for algebraic effects

We provide a syntactic analysis of contextual preorder and equivalence for a polymorphic programming language with effects. Our approach applies uniformly across a range of algebraic effects, and incorporates, as instances: errors, input/output, global state, nondeterminism, probabilistic choice, and combinations thereof. Our approach is to extend Plotkin and Power’s structural operational semantics for algebraic effects (FoSSaCS 2001) with a primitive “basic preorder” on ground type computation trees. The basic preorder is used to derive notions of contextual preorder and equivalence on program terms. Under mild assumptions on this relation, we prove fundamental properties of contextual preorder (hence equivalence) including extensionality properties and a characterisation via applicative contexts, and we provide machinery for reasoning about polymorphism using relational parametricity

Language proficiency among immigrants and the establishment of interethnic relations: a comparative analysis of Bilbao, Lisbon and Rotterdam

Despite the increasing interest in exploring language proficiency among immigrants as a quintessential element for their economic integration in the host country, less attention has been devoted to the social impacts that destination-language proficiency may have on enhancing interethnic contacts between immigrants and the native population. This research aims to shed light on this latter topic, discussing if being a native-speaker immigrant in the host country or, for those immigrants who are non-native speakers, having a stronger command of the destination-language may increase their likelihood of interacting with the native population. Moreover, we question if there are significant differences in the interaction patterns between these two groups and the natives, presenting the cities of Bilbao, Lisbon and Rotterdam as a territorial frame. The analysis is based on data gathered through the GEITONIES survey. The results obtained indicate that native-speaker immigrants generally tend to show more interaction with the natives. Nevertheless, for immigrants not sharing such cultural similarity, those with a higher level of second-language proficiency clearly show stronger bonds with the native population; in both cases this can also be related to individual, group or place related variables

Two Algebraic Process Semantics for Contextual Nets

We show that the so-called 'Petri nets are monoids' approach initiated by Meseguer and Montanari can be extended from ordinary place/transition Petri nets to contextual nets by considering suitable non-free monoids of places. The algebraic characterizations of net concurrent computations we provide cover both the collective and the individual token philosophy, uniformly along the two interpretations, and coincide with the classical proposals for place/transition Petri nets in the absence of read-arcs

Dependent plural pronouns with Skolemized choice functions

The present paper discusses two interesting phenomena concerning phi-features on plural pronouns: (i) plural pronouns that denote atomic individuals (‘dependent plural pronouns’), and (ii) plural pronouns with more than one binder (‘partial binding’). A novel account of these two phenomena is proposed, according to which all occurrences of phi-features are both semantically and morphologically relevant. For such a ‘uniformly semantic account’ of phi-features, dependent plural pronouns constitute a theoretical challenge, while partial binding is more or less straightforwardly accounted for. In order to make sense of the semantic effects of the phi-features on dependent plural pronouns, the following idea is pursued: the phi-features on a dependent plural pronoun reflect the range of values that the pronoun takes, rather than the particular value it denotes at a time. This idea is implemented in a compositional semantics by making use of (Skolemized) choice functions. An appealing feature of the present account is that, unlike its predecessors, it accounts for dependent plural pronouns without c-commanding antecedents in essentially the same way as for those with c-commanding antecedents. It is also shown how this account of dependent plural pronouns can straightforwardly be augmented with set indices to account for partial binding

On a Connection between Procedural and Applicative Languages

This paper reports on the connection between procedural and applicative languages. It presents features, notions and methods derived from abstract data type theory that in our judgement are helpful and necessary for multi-level software engineering environments in general, and especially for the treatment of verification issues there. Reference is made to an existing software engineering system and exemplary languages of it. A denotational semantics based on algebraic structures is introduced and employed. Since object-orientedness is looked at as one of the most important properties of such environments the notion of correctness is applied to objects and object relations. Finally a realistic semi-automatic method for the check of correctness criteria is given, accompanied by remarks on our existing implementation

A Generic Operational Metatheory for Algebraic Effects

We provide a syntactic analysis of contextualpreorder and equivalence for a polymorphic programminglanguage with effects. Our approach applies uniformly acrossa range of algebraic effects, and incorporates, as instances:errors, input/output, global state, nondeterminism, probabilisticchoice, and combinations thereof. Our approach is toextend Plotkin and Power’s structural operational semanticsfor algebraic effects (FoSSaCS 2001) with a primitive “basicpreorder” on ground type computation trees. The basic preorderis used to derive notions of contextual preorder andequivalence on program terms. Under mild assumptions onthis relation, we prove fundamental properties of contextualpreorder (hence equivalence) including extensionality propertiesand a characterization via applicative contexts, and weprovide machinery for reasoning about polymorphism usingrelational parametricity

Epistemic invariantism and speech act contextualism

In this essay I show how to reconcile epistemic invariantism with the knowledge account of assertion. My basic proposal is that we can comfortably combine invariantism with the knowledge account of assertion by endorsing contextualism about speech acts. My demonstration takes place against the backdrop of recent contextualist attempts to usurp the knowledge account of assertion, most notably Keith DeRose's influential argument that the knowledge account of assertion spells doom for invariantism and enables contextualism's ascendanc