A Tool for Model-Based Language Specification

Syntax Tree Concrete Syntax Model Abstract Syntax Model instance of instance of Textual Representation Parser input output Figure 1 Traditional language processing approach. sign process. In principle, it might not be even necessary for the language designer to have advanced knowledge on parser generators when following a model-driven language specification approach. • A full-blown model-driven language workbench [18] would allow the modification of a language abstract syntax model and the automatic generation of a working IDE on the run. The specification of domain-specific languages would become easier, as the language designer could play with the language specification and obtain a fully-functioning language processor on the fly, without having to worry about the propagation of changes throughout the complete language processor tool chain. In short, the model-driven language specification approach brings domain-driven design [14] to the domain of language design. It provides the necessary infrastructure for what Evans would call the ‘supple design’ of language processing tools: the intention-revealing specification of languages by means of abstract syntax models, the separation of concerns in the design of language processing tools by means of declarative ASM-CSM mappings, and the automation of a significant part of the language processor implementation. C. Comparison with the Traditional Approach A diagram summarizing the traditional language design process is shown in Figure 1, whereas the corresponding diagram for the model-based approach proposed in this paper is shown in Figure 2. When following the traditional grammar-driven approach, the language designer starts by designing the grammar corresponding to the concrete syntax of the desired language, typically in BNF or a similar format. Then, the designer annotates the grammar with attributes and, probably, semantic actions, so that the resulting attribute grammar can be fed into lexer and parser generator tools that produce the corresponding lexer and parser, respectively. The resulting syntaxdirected translation process generates abstract syntax Context-Free Grammar e.g. BNF Conceptual Model Textual Representation Parser Abstract Syntax Graph Concrete Syntax Model Abstract Syntax Model instance of instance of