Toward live domain-specific languages

Software and Systems Modeling - Live programming is a style of development characterized by incremental change and immediate feedback. Instead of long edit-compile cycles, developers modify a...     

Embedding domain-specific modelling languages in Maude specifications

We propose a formal approach for the definition and analysis of domain-specific modelling languages (dsml). The approach uses standard model-driven engineering artifacts for defining a language’s syntax (using metamodels) and its operational semantics (using model transformations). We give formal meanings to these artifacts by translating them to the Maude language: metamodels and models are mapped to equational specifications, and model transformations are mapped to rewrite rules between such specifications, which are also expressible in Maude due to Maude’s reflective capabilities. These mappings provide us, on the one hand, with abstract definitions of the mde concepts used for defining dsml, which naturally capture their intended meanings; and, on the other hand, with equivalent executable definitions, which can be directly used by Maude for formal verification. We also study a notion of operational semantics-preserving model transformations, which are model transformations between two dsml that ensure that each execution of a transformed instance is matched by an execution of the original instance. We propose a semi-decision procedure, implemented in Maude, for checking the semantics-preserving property. We also show how the procedure can be adapted for tracing finite executions of the transformed instance back to matching executions of the original one. The approach is illustrated on xspem, a language for describing the execution of activities constrained by time, precedence, and resource availability.     

Supporting user-oriented analysis for multi-view domain-specific visual languages

The integration of usable and flexible analysis support in modelling environments is a key success factor in Model-Driven Development. In this paradigm, models are the core asset from which code is automatically generated, and thus ensuring model correctness is a fundamental quality control activity. For this purpose, a common approach is to transform the system models into formal semantic domains for verification. However, if the analysis results are not shown in a proper way to the end-user (e.g. in terms of the original language) they may become useless.In this paper we present a novel DSVL called BaVeL that facilitates the flexible annotation of verification results obtained in semantic domains to different formats, including the context of the original language. BaVeL is used in combination with a consistency framework, providing support for all steps in a verification process: acquisition of additional input data, transformation of the system models into semantic domains, verification, and flexible annotation of analysis results.The approach has been validated analytically by the cognitive dimensions framework, and empirically by its implementation and application to several DSVLs. Here we present a case study of a notation in the area of Digital Libraries, where the analysis is performed by transformations into Petri nets and a process algebra.     

Formalizing the structural semantics of domain-specific modeling languages

Model-based approaches to system design are now widespread and successful. These approaches make extensive use of model structure to describe systems using domain-specific abstractions, to specify and implement model transformations, and to analyze structural properties of models. In spite of its general importance the structural semantics of modeling languages are not well-understood. In this paper we develop the formal foundations for the structural semantics of domain-specific modeling languages (DSML), including the mechanisms by which metamodels specify the structural semantics of DSMLs. Additionally, we show how our formalization can complement existing tools, and how it yields algorithms for the analysis of DSMLs and model transformations.

Measuring the complexity of domain-specific languages developed using MDD

The standard ISO/IEC 25010 (SQuaRE) defines appropriateness as one of the three components of functional suitability, the other two components being completeness and correctness. As users of domain-specific language (DSL) are quite often domain experts with limited programming skills, a DSL might be considered appropriate if the resulting domain-specific programs do not contain an excessive amount of nondomain-related programming elements. This paper describes a metric for measuring the appropriateness of DSLs that are developed using model-driven development (MDD), its evaluation and use. The metric measures the depth of the deepest domain-specific command within abstract syntax trees generated by a DSL. It is aimed at being used during the development of a new DSL and for comparing different DSLs defined over the same domain. It is assumed that during MDD, the metamodel describes the domain-independent part of the DSL, while the model supplies the domain-specific part. This resembles the implementation of DSLs using existing metaprogramming tools that provide off-the-shelf implementations of programming constructs but require manual implementation of the domain-specific language elements.     

Automating the construction of domain-specific modeling languages for object-oriented frameworks

The extension of frameworks with domain-specific modeling languages (DSML) has proved to be an effective way of improving the productivity in software product-line engineering. However, developing and evolving a DSML is typically a difficult and time-consuming task because it requires to develop and maintain a code generator, which transforms application models into framework-based code. In this paper, we propose a new approach for extending object-oriented frameworks that aims to alleviate this problem. The approach is based on developing an additional aspect-oriented layer that encodes a DSML for building framework-based applications, eliminating the need of implementing a code generator. We further show how a language workbench is capable of automating the construction of DSMLs using the proposed layer.     

Synchronization of abstract and concrete syntax in domain-specific modeling languages

Modern domain-specific modeling (DSM) frameworks provide refined techniques for developing new languages based on the clear separation of conceptual elements of the language (called abstract syntax) and their graphical visual representation (called concrete syntax). This separation is usually achieved by recording traceability information between the abstract and concrete syntax using mapping models. However, state-of-the-art DSM frameworks impose severe restrictions on traceability links between elements of the abstract syntax and the concrete syntax. In the current paper, we propose a mapping model which allows to define arbitrarily complex mappings between elements of the abstract and concrete syntax. Moreover, we demonstrate how live model transformations can complement mapping models in providing bidirectional synchronization and implicit traceability between models of the abstract and the concrete syntax. In addition, we introduce a novel architecture for DSM environments which enables these concepts, and provide an overview of the tool support.     

Advanced and efficient execution trace management for executable domain-specific modeling languages

Executable Domain-Specific Modeling Languages (xDSMLs) enable the application of early dynamic verification and validation (V&V) techniques for behavioral models. At the core of such techniques, execution traces are used to represent the evolution of models during their execution. In order to construct execution traces for any xDSML, generic trace metamodels can be used. Yet, regarding trace manipulations, generic trace metamodels lack efficiency in time because of their sequential structure, efficiency in memory because they capture superfluous data, and usability because of their conceptual gap with the considered xDSML. Our contribution is a novel generative approach that defines a multidimensional and domain-specific trace metamodel enabling the construction and manipulation of execution traces for models conforming to a given xDSML. Efficiency in time is improved by providing a variety of navigation paths within traces, while usability and memory are improved by narrowing the scope of trace metamodels to fit the considered xDSML. We evaluated our approach by generating a trace metamodel for fUML and using it for semantic differencing, which is an important V&V technique in the realm of model evolution. Results show a significant performance improvement and simplification of the semantic differencing rules as compared to the usage of a generic trace metamodel.

     

Formal validation of domain-specific languages with derived features and well-formedness constraints

Despite the wide range of existing tool support, constructing a design environment for a complex domain-specific language (DSL) is still a tedious task as the large number of derived features and well-formedness constraints complementing the domain metamodel necessitate special handling. Such derived features and constraints are frequently defined by declarative techniques (such graph patterns or OCL invariants). However, for complex domains, derived features and constraints can easily be formalized incorrectly resulting in inconsistent, incomplete or ambiguous DSL specifications. To detect such issues, we propose an automated mapping of EMF metamodels enriched with derived features and well-formedness constraints captured as graph queries in EMF-IncQuery or (a subset of) OCL invariants into an effectively propositional fragment of first-order logic which can be efficiently analyzed by back-end reasoners. On the conceptual level, the main added value of our encoding is (1) to transform graph patterns of the EMF-IncQuery framework into FOL and (2) to introduce approximations for complex language features (e.g., transitive closure or multiplicities) which are not expressible in FOL. On the practical level, we identify and address relevant challenges and scenarios for systematically validating DSL specifications. Our approach is supported by a tool, and it will be illustrated on analyzing a DSL in the avionics domain. We also present initial performance experiments for the validation using Z3 and Alloy as back-end reasoners.     

Using internal domain-specific languages to inherit tool support and modularity for model transformations

Software and Systems Modeling - Model-driven engineering (MDE) has proved to be a useful approach to cope with today’s ever-growing complexity in the development of software systems;...     

Program comprehension of domain-specific and general-purpose languages: comparison using a family of experiments

Domain-specific languages (DSLs) are often argued to have a simpler notation than general-purpose languages (GPLs), since the notation is adapted to the specific problem domain. Consequently, the impact of domain relevance on the creation of the problem representation is believed to improve programmers’ efficiency and accuracy when using DSLs compared with using similar solutions like application libraries in GPLs. Most of the common beliefs have been based upon qualitative conclusions drawn by developers. Rather than implementing the same problem in a DSL and in a GPL and comparing the efficiency and accuracy of each approach, developers often compare the implementation of a new program in a DSL to their previous experiences implementing similar programs in GPLs. Such a conclusion may or may not be valid. This paper takes a more skeptical approach to acceptance of those beliefs. By reporting on a family of three empirical studies comparing DSLs and GPLs in different domains. The results of the studies showed that when using a DSL, developers are more accurate and more efficient in program comprehension than when using a GPL. These results validate some of the long- held beliefs of the DSL community that until now were only supported by anecdotal evidence.     

Dealing with variability within a family of domain-specific languages: comparative analysis of different techniques

Almost a decade has passed since the OMG has issued the Model Driven Architecture (MDA) initiative. It soon became obvious that raising the level of abstraction in development and reasoning at the model level would help in asking the right questions at the right time. Based on a concrete problem, we discuss four alternative solutions to a multi-language system design problem. These solutions use a traditional approach, a technique based on modeling, a domain-specific approach, and a mix of modeling and domain-specific techniques, respectively. The solutions depend on the problem, but they are representative for the situations we encounter in practice, therefore giving us a good basis for a larger discussion on the appropriateness of using modeling techniques and on the place of MDA in current software engineering practice and design.     

Sequential versus concurrent languages of labeled conflict-freePetri nets

For structurally deterministic labeled conflict-free Petri nets (PNs), we show that two PNs have identical sequential languages if and only if their concurrent languages are identical as well, and whether a given labeled conflict-free PN is structurally deterministic or not can be checked in polynomial time. We also investigate a number of language-related problems in supervisory control theory for this class of PNs. As it turns out, the properties of controllability, observability, and normality in the sequential framework coincide with that in the concurrent framework     

Program comprehension of domain-specific and general-purpose languages: replication of a family of experiments using integrated development environments

Domain-specific languages (DSLs) allow developers to write code at a higher level of abstraction compared with general-purpose languages (GPLs). Developers often use DSLs to reduce the complexity of GPLs. Our previous study found that developers performed program comprehension tasks more accurately and efficiently with DSLs than with corresponding APIs in GPLs. This study replicates our previous study to validate and extend the results when developers use IDEs to perform program comprehension tasks. We performed a dependent replication of a family of experiments. We made two specific changes to the original study: (1) participants used IDEs to perform the program comprehension tasks, to address a threat to validity in the original experiment and (2) each participant performed program comprehension tasks on either DSLs or GPLs, not both as in the original experiment. The results of the replication are consistent with and expanded the results of the original study. Developers are significantly more effective and efficient in tool-based program comprehension when using a DSL than when using a corresponding API in a GPL. The results indicate that, where a DSL is available, developers will perform program comprehension better using the DSL than when using the corresponding API in a GPL.