practical models in practice

Practical Modelsin Practicewww.lukas-renggli.ch

Practical Models of Models in Practice

www.lukas-renggli.ch

Practical Meta-Models in Practice

www.lukas-renggli.ch

‣ Software Engineer at GoogleYouTube Video Analytics

‣ SCG AlumniBachelor, Master and PhD

‣ Open-Source CommunitiesSeaside, Magritte and PierHelvetia, PetitParser

Lukas Renggli

Roadmap1. Protocol Buffers

Meta-data model for serialization2. Magritte

Meta-model for generic services3. Google Web Toolkit

Model-driven web architecture4. Helvetia

Meta-model for programming languages

1Protocol BuffersMeta-data model for serialization

Protocol Buffers

‣ Encode structured data‣ Language-neutral‣ Platform-neutral‣ Extensible‣ Efficient

Protocol Buffer IDL

message Person {  required int32 id = 1;  required string name = 2;  optional string email = 3;}

message Person {  required int32 id = 1;  required string name = 2;  optional string email = 3;}

C++

protoc

Serialize in C++

Person person;person.set_name("John Doe");person.set_id(1234);person.set_email("jdoe@example.com");

fstream output("myfile", ios::out | ios::binary);person.SerializeToOstream(&output);

Deserialize in Python

file = open("myfile", "rb")person = Person()person.ParseFromString(file.read())file.close

print "Name: ", person.nameprint "E-mail: ", person.email

Demo

Why not XML/JSON?

‣ Protocol Buffers are– 3—10 times smaller– 20—100 times faster– consistent code generators– less ambiguous– evolvable

message Person {  required int32 id = 1;  required string name = 2;  optional string email = 3;}

message Person {  required int32 id = 1;  required string name = 2;  repeated string email = 3; repeated Phone phone = 4;}

:Person:Person

:Person

‣ Describe your data once, and use it across platforms and languages‣ Evolution supported by design‣ Used at Google for almost all

– data storage (file formats, database)– remote procedure protocols (RPC)

2MagritteMeta-model for generic services

Address Object

street = 'Schützenmattstrasse'plz = 3012place = 'Bern'canton = 'Bern'

:Address

Address Class

street = 'Schützenmattstrasse'plz = 3012place = 'Bern'canton = 'Bern'

:Address

street: Stringplz: Integerplace: Stringcanton: String

Address

class

Address Description

street = 'Schützenmattstrasse'plz = 3012place = 'Bern'canton = 'Bern'

:Address

label = 'Street'

:StringDescription

label = 'PLZ'required = truerange = 1000..9999

:NumberDescription

label = 'Place'required = true

:StringDescription

label = 'Canton'required = truesorted = trueoptions = #( 'Bern' 'Zurich' ... )

:SingleOptionDescription

label = 'Address'

:Containerdescription

Magritte

result := anAddress asMorph addButtons; addWindow; callInWorld

User Interfaces

result := self call: (anAddress asComponent addValidatedForm; yourself)

Web Interfaces

*

*

*

Other ServicesViewers

EditorsReports

ValidationFiltering

Serialization

Copying

IndexingInitialization

Initialization

ExtensionAdaptation

Customization

Domain Model

Metamodel

Meta-

Metamodel

<described-by>

<described-by>

Developer

End User

Domain Model

Metamodel

Meta-

Metamodel

Magritte

Developer

<described-by>

<described-by>

Magritte

End User

Adaptive Object Model

Run-time

End userscustomizability

Demo

‣ Very powerful and flexible‣ Runtime adaptive code‣ End-user programmable code‣ Can cause meta meta-confusion‣ Can be slower than hardcoding

Magritte

3Google Web ToolkitModel-driven web architecture

public class Main implements EntryPoint { public void onModuleLoad() { Label label = new Label(“Hello World”); RootPanel.add(label); }}

Is this really a model?

public class Main implements EntryPoint { public void onModuleLoad() { Label label = new Label(“Hello World”); RootPanel.add(label); }}

Is this really a model?

High-levelWidgets

public class Main implements EntryPoint { public void onModuleLoad() { Label label = new Label(“Hello World”); RootPanel.add(label); }}

Is this really a model?

High-levelWidgets

DescriptionLanguage

platformindependentmodel

modeltransformation

public class Main implements EntryPoint { public void onModuleLoad() { Label label = new Label(“Hello World”); RootPanel.add(label); }}

Transformation

Mozilla Chrome Safari IE ...

English

French

German

...

‣ Write JavaScript using a high-level widget library in a well defined (statically typed) language‣ Translate and optimize code towards

specific browsers‣ Debugging actually works nowadays

GWT

4HelvetiaMeta-model for programming languages

He vetia

ProgrammingLanguage

Model

a..z a..z

0..9

ID  ::=  letter  {  letter  |  digit  }  ;

scanIdentifier self step. ((currentCharacter between: $A and: $Z) or: [ currentCharacter between: $a and: $z ]) ifTrue: [ [ self recordMatch: #IDENTIFIER. self step. (currentCharacter between: $0 and: $9)or: [ (currentCharacter between: $A and: $Z) or: [ currentCharacter between: $a and: $z ] ] ] whileTrue. ^ self reportLastMatch ]

#(#[1 0 9 0 25 0 13 0 34 0 17 0 40 0 21 0 41] #[1 0 9 0 25 0 13 0 34 0 93 0 76 0 157 0 112] #[1 2 38 0 21 2 38 0 25 2 38 0 26 0 13 0 34] #[0 1 154 0 16 0 21 0 25 0 26 0 34 0 40 0 41] #[0 1 210 0 76 0 81] #[0 1 214 0 76 0 81] #[1 0 173 0 76 0 177 0 81] #[0 1 134 0 16 0 21 0 25 0 26 0 34 0 40 0 41] #[1 1 46 0 21 1 46 0 25 1 46 0 26 1 69] #[1 1 54 0 21 1 54 0 25 1 54 0 26 1 54 0 34] #[0 2 102 0 21 0 25 0 26 0 34 0 40 0 41 0 76]

#[0 2 50 0 21 0 25 0 26 0 76 0 79] #[1 1 13 0 76 2 85 0 124 1 21 0 125] #[1 2 89 0 17 2 30 0 21 2 30 0 82] #[1 2 93 0 21 2 97 0 82] )

a..z a..z

0..9

ID  ::=  letter  {  letter  |  digit  }  ;

44

letter

letter digit

sequence

choice

many

ID  ::=  letter  {  letter  |  digit  }  ;

45

letter

letter digit

sequence

choice

many

46

Transformable

Composable

Extensible

Customizable

letter

letter digit

sequence

choice

many

47

He vetiaContextual

Menus

NavigationSearch

CodeExpansion

ErrorCorrection

CustomInspector

Refactorings

CodeFolding

CodeHighlighting

Debuggers

Editors

Demo

‣ Grammar is the meta-model‣ Composable programming languages‣ Extensible programming languages‣ Tooling is built around the grammar

He vetia

StructuralModel

BehavioralModel

Run-

time

Stat

icRu

n-tim

eAd

aptiv

e

He vetia

“Meta-models are the enablers ofpractical software development.”

www.lukas-renggli.ch

He vetia