Creating a textual domain specific language

transcript

Software ArchitectureS

Software ArchitecturePart III

Class #2

Creating a domain-specific language

Vicente García Díaz2014

University of Oviedo

What is a domain-specific language?

• It is a programming language that focuses only on a particular domain

• The domain can be anything

• Opposite ideas▫ General-Purpose Language (GPL)

Java, C, C++, C#, Python, UML, …

▫ Domain-Specific Language (DSL)

CSS, HTML, SQL

Classification (I)

• From the point of view of how the language is

Textuals Graphicals

Classification (II)

• From the point of view of the problem domain

Horizontals Verticals

Stakeholders

Engineers

Clients

Developers

Limits

• It is desirable to set limits to determine which parts of the system will be created with a DSL and which parts will not

• Sometimes it is better to use a GPL and other times it is better to use a DSL

• Using DLSs has both advantages and disadvantages

Benefits of using DSLs

1. With a DSL, it is more difficult to make mistakes in the representation of a problem domain

2. Working with the terms of a specific domain facilitates the understanding of the models that represents the software to non-experts in computer technology development

3. When knowledge of a particular domain is captured in a model, it becomes much easier to perform migrations between different technologies

Drawbacks of using DSLs

1. Research time to define and design the DSL thatwill be created

2. Cost required to test the DSL

3. Additional difficulties in the application deployment

4. Need for additional documentation

5. Preparation of the development team

How a DSL is usually created?

• They are usually created using parser generators▫ From a grammar they obtain the parser

▫ ANTLR, JavaCC, Lexx/yacc, …

• The parser validates the text

and created a tree▫ It is usually an Abstract

Syntax Tree (AST)

addition

multiplication literal

literal literal

5*6 + 25

A difficult task

• Writing a parser is a difficult task▫ Even using tools like ANTLR

• …a we would still need:▫ Creating a development environment for the language

▫ Transform the AST in “something” from which we are able to generate code

• It is better not to do it “by hand”▫ Textual Modeling Framework we will focus on

▫ Graphical Modeling Framework

What is Xtext?

• It is a tool to build DSLs or even GPLs

• It automatically generates various artifacts from a LL(*) grammar ▫ A parser

▫ A Ecore metamodel

▫ An IDE for Eclipse

Syntax highlighting

Assistance in completing sentences

Overview window

Checking of constrains in real time

Generador

Metamodelo

Gramática Xtext

(Petri.xtext)

Parser ANTLR

Editor Plug-in

Proyecto del DSL “Petri”

Proyecto UI

Xtextgrammar

ANTL Parser

Ecoremetamodel

Plugingfor

Eclipse

Xtextgenerator

DSL Project

What is our goal with Xtext?

1. Creating a domain-specific language (textual) based on Xtext

2. Creating programs (models) using the createdlanguage

3. Generaring artifacts from the models (e.g., Java source code, HTML, plain text, assembly code, …)

Developing process with Xtext

1. Part I. Creation of the language▫ Step 1. Creating a Xtext Project in Eclipse▫ Step 2. Defining the gramar of the language…and many

other things▫ Step 3. Generating the language of all of its components

2. Part II. Creation of programs (models) with the new language

▫ Step 1. Opening the development environment of thelanguage

▫ Step 2. Creating a program for the new language usingthe development environment

3. Part III. Generation of artifacts from the models

Installing the environment. Option 1

• Download Eclipse for Xtext

• http://www.eclipse.org/Xtext/download.html

• Download Eclipse Modeling Tools

• http://www.eclipse.org/downloads/packages/eclipse-modeling-tools/lunasr1

• Install Xtext as a plugin for the Eclipse IDE

do Creating a domain-specific language

Thank you