Model-Driven Software Development

Course IN4308Master Computer Science

Delft University of Technology

Eelco Visserhttp://eelcovisser.org

Lecture1: Introduction & Overview

“Generator spits out ‘mobile’ applications”

Source: Automatiseringsgids January 16, 2010

“Steape has developed a code generator that automatically generates code for a range of mobile phones”

Software Engineering

ProblemDomain

SolutionDomain

implement

validate

Programming Languages

"A programming language is low level when its programs require attention to the irrelevant."

Programming Languages

Alan J. Perlis. Epigrams on Programming. SIGPLAN Notices, 17(9):7-13, 1982.

Machine Language to Assembly Language

   Machine Language       169 1 160 0 153 0 128 153 0 129 153 130 153 0 131 200 208 241 96

   BASIC       5 FOR I=1 TO 1000: PRINT "A";: NEXT I

Program I-I. Disassembly.

., 0360 A9 01    LDA #$01

., 0362 A0 00    LDY #$00

., 0364 99 00 80 STA $8000,Y

., 0367 99 00 81 STA $8100,Y

., 036A 99 00 82 STA $8200,Y

., 036D 99 00 83 STA $8300,Y

., 0370 C8       INY

., 0371 D0 F1    BNE $0364

., 0373 60       RTS

.

Source: http://www.atariarchives.org/mlb/introduction.php

“Let's examine some advantages of ML, starting with the main one - ML runs extremely fast.”

From Instructions to Expressions

mov &a, &cadd &b, &cmov &a, &t1sub &b, &t1and &t1,&c

Source: http://sites.google.com/site/arch1utep/home/course_outline/translating-complex-expressions-into-assembly-language-using-expression-trees

c = ac += bt1 = at1 -= bc &= t1

c = (a + b) & (a - b)

From Calling Conventions to Procedures

calc: push eBP ; save old frame pointer mov eBP,eSP ; get new frame pointer sub eSP,localsize ; reserve place for locals . . ; perform calculations, leave result in AX . mov eSP,eBP ; free space for locals pop eBP ; restore old frame pointer ret paramsize ; free parameter space and return

f(e1,e2,...,en)

push eAX ; pass some register resultpush byte[eBP+20] ; pass some memory variable (FASM/TASM syntax)push 3 ; pass some constantcall calc ; the returned result is now in eAX

f(x) { ... }

http://en.wikipedia.org/wiki/Calling_convention

From Malloc/Free to Automatic Memory Management

/* Allocate space for an array with ten elements of type int. */

int *ptr = (int*)malloc(10 * sizeof (int));if (ptr == NULL) { /* Memory could not be allocated, the program should handle the error here as appropriate. */} else { /* Allocation succeeded. Do something. */ free(ptr); /* We are done with the int objects, and free the associated pointer. */ ptr = NULL; /* The pointer must not be used again, unless re-assigned to using malloc again. */}

http://en.wikipedia.org/wiki/Malloc

int [] = new int[10];/* use it; gc will clean up (hopefully) */

Abstractions in Programming Languages

❖ Structured control-flow

★ if-then-else, while

❖ Procedural abstraction

★ procedures, first-class functions (closures)

❖ Memory management

★ garbage collection

❖ Data abstraction

★ abstract data types, objects

❖ Modules

★ inheritance, traits, mixins

Abstraction

Programming Languages

procedures

expressions

garbage collection

structured control-flow

objects

machine

Scala

Abstractions in Programming Languages

Linguistic Abstraction

identify pattern

use new abstraction

language A language Bdesign abstraction

High-level languages reduce problem/solution gapWhat is the Next Level of Abstraction?

ProblemDomain HLL Machine

Do HLLs Eliminate All Irrelevant Detail?

What about

❖ data persistence

❖ data services

❖ concurrency

❖ distribution

❖ access control

❖ data invariants

❖ workflow

❖ ...

High-level languages reduce problem/solution gapWhat is the Next Level of Abstraction?

ProblemDomain HLL Machine

Model-Driven Software Development

ProblemDomain HLL MachineModel

models further reduce gap between problem domain and implementation

What is a model?

What is a model?

thingmodel

ofthing

abstraction

abstraction = forgetting details

What is a model?

“A model is a simplification of a system built with an intended goalin mind. The model should be able to answer questions in place of

the actual system.” Jean Bézivin

“A model is an abstraction of a (real or language based) systemallowing predictions or inferences to be made.” Kuehne

“Models help in developing artefacts by providing informationabout the consequences of building those artefacts before they

are actually made.” Ludewig

“A model of a system is a description or specification of that systemand its environment for some certain purpose.” OMG

What is a model?

A model

❖ is a simplification of a system

★ abstraction, description, specification, information

❖ can answer questions in place of actual system

★ analysis, inference, predictions

❖ is used for a purpose

★ understanding, planing, risk analysis, ...

A model is a UML diagram

simplification?analysis?purpose?

What is a model about?

❖ Structure

★ Data

★ Architecture

★ Configuration

❖ Behaviour

★ User interface

★ Access control

★ Business process

❖ About any aspects of a system

A model can be a UML diagram ...

A model can be a UML diagram ...

e = x | e + e | e - e | f(e,...,e)

... but it can be any other representation ...

... that serves the purpose of abstraction, analysis, etc.

For what purposes are models used?

Description

❖ of something that exists

Analysis

❖ understanding of properties

Blueprint

❖ guidelines to build something

Specification

❖ precise instruction for construction (code gen)

Model-Driven Architecture (MDA)

Vision from OMG

❖ Models at different level of abstraction

★ Platform Independent Model (PIM)

★ Platform Specific Model (PSM)

❖ Model transformation

★ e.g. PIM to PSM to implementation

★ transformations not necessarily automatic

❖ UML as standard modeling language

★ models are ‘visual’ or ‘graphical’

‘Formal Methods’ Formal Methods

ProblemDomain HLL Machine

Logic

A Critique of MDA & Formal Methods

General purpose modeling languages

❖ High coverage

★ large class of software systems

❖ Low expressivity

★ irrelevant details

★ Requirements/implementation gap not reduced

Domain-Specific Languages

ProblemDomain HLL MachineDSL

domain-specific languages: models specialized to an application domain

DSLs Provide Domain-Specific ...

Abstractions

★ directly represent domain concepts

Concrete syntax

★ natural notation

Optimization

★ based on domain assumptions

Error checking

★ report errors in terms of domain concepts

Tool support

★ interpreter, compiler, code generator, IDE

Example Domain-Specific Languages (1)

Spreadsheet

★ formulas, macros

Querying

★ SQL, XQuery, XPath

Graph layout

★ GraphViz

Web

★ HTML, CSS, RSS, XML, XSLT

★ Ruby/Rails, JSP, ASP, JSF, WebDSL

Example Domain-Specific Languages (2)

Games

★ Lua, UnrealScript

Modeling

★ UML, OCL, QVT

Language processing

★ YACC, LEX, RegExp, ANTLR, SDF

★ TXL, ASF+SDF, Stratego

TransformationTransformation

System

ModelmigrationModel

construct

analysisModel

extract

External DSL

Dedicated language

★ independent of host/target language (portable)

★ implementation with interpreter or compiler

Advantages

★ language tuned to domain

★ domain-specific errors, analysis, optimizations

Disadvantages

★ cost of learning new language

★ cost of maintaining language

Internal DSL

Library in HLL

★ Haskell, Scala, Ruby, ...

★ API is language

★ language features for ‘linguistic abstraction’

Advantages

★ host language = implementation language

Disadvantages

★ host language = implementation language (encoding)

★ lack of portability

★ no domain-specific errors, analysis, optimization

Course Goal

Learn to design and implement domain-specific languages

Understand DSL design choices and make reasoned decisions about their application

Course Goal

abstraction

ApplicationDomain

domain analysis

ProgrammingPatterns

LanguageDesign

DSLlanguage definition

The Linguistic Abstraction Process

Lectures* (15x)

Designs (2x)

Essay (1x)

*we have 15 slots for lectures; we don’t need to use them all

Course Ingredients

Software Development with Domain-Specific Languages

Quarter 3(February - March 2011)

Extension and Evolution of DSLs

Lecture 2

Codecustomize

Model

generate

Lecture 4

WebDSL: a DSL for Web Programming

Lecture 4

Mobl: a DSL for Mobile Web Applications

Guest Lecture by Markus Voelter

Lectures 5

A Reactive State-Based DSL for Fountain Control

Guest Lecture by Sander Vermolen

Lectures 6

Automated Coupled Data Evolution

Lectures 7

Domain-Driven Design

Guest Lecture by André Boonzaaijer

(Sogyo)

Domain-Driven Design

Design1: Software Development with DSLs

Facebook

❖ Status updates selectively accessible to friends

❖ Web application in WebDSL

❖ Mobile application in mobl connected to web app using services

❖ Work in group of 2 to 4 students

Deadline: April 7

❖ submit code and arrange demonstration

Quarter 4(April - May 2011)

Design and Implementation of Domain-Specific Languages

Spoofax: a DSL for Editor Services

Lecture 8

SDF: a DSL for Syntax Definition

Lecture 8

Stratego: a DSL for Transformation

Lecture 9

Code Generation Techniques and Applications

Lecture 10

Code Generation

❖ Print statements

❖ String composition

❖ Template engines

❖ String interpolation

❖ Abstract syntax

❖ Concrete object syntax

Embedded DSLs

❖ MetaBorg, StringBorg

Advanced Topics

Lectures 11-15

❖ Portability

★ supporting multiple platforms

❖ Internal DSLs

★ library as a language

❖ Language composition

★ combining multiple DSLs

❖ Economics

★ costs and benefits of developing (with) DSLs

Design 2: Design and Implementation of DSLs

Design and implement a DSL with Spoofax

❖ use rule-based DSLs for language definition

❖ create full fledged IDE

You propose web app and language to design

❖ (We can give tips if you’re stuck)

❖ Deadline for proposal: March 22

Essay: Individual Writing Project

Read

❖ recommended papers

❖ http://researchr.org/bibliography/mdsd

Write

❖ a paper about software development with and of domain-specific languages.

★ Reflect on your experience in design projects

★ Reflect on the literature you’ve read

final grade =

❖ 0.35 * design1

❖ 0.4 * design2

❖ 0.25 * essay

all grades should be >= 6

Grading

Feedback

I’d like to get feedback early; not when it is too late to fix

Schedule

Read

❖ Czarnecki: Overview of Generative Development

❖ Muller et al.: Modeling Modeling

Lecture 2 (February 3)

❖ Extension and evolution of DSLs

Lecture 3 (February 8)

❖ WebDSL: a DSL for Web Programming

Lecture 4 (February 10)

❖ Mobl: a DSL for Mobile Web Applications