SLE meets MDE and CompilationClément Guy, Steven Derrien, Benoît Combemale, Jean-Marc Jézéquel

Triskell & Cairn teams

IRISA-INRIA

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General-purpose

Language

<<represents>>

<<conformsTo>>

Complex software systems (including

compilers)

3

<<represents>>

DSL1

DSL2 DSL3

DSL4

<<conformsTo>>

<<conformsTo>><<conformsTo>>

<<conformsTo>>

DSL1

DSL2 DSL3

DSL4

<<represents>>

<<conformsTo>>

<<conformsTo>><<conformsTo>>

<<conformsTo>>

DSL1

DSL2 DSL3

DSL4

<<represents>>

<<conformsTo>>

<<conformsTo>><<conformsTo>>

<<conformsTo>>

4

<<represents>>

<<conformsTo>>

DSL1

DSL2 DSL3

DSL4

<<represents>>

<<conformsTo>>

<<conformsTo>><<conformsTo>>

<<conformsTo>>

Our Motivations and Challenges

• Language multiplication

▫ Need for operations capitalization

▫ Need for inter-languages mappings

• Language operations multiplication

▫ Need for ways to ensure a sound combination of these operations

• Need for “best practices” for language definition

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Capitalization Example:

Dead Code Elimination/Trimming

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if (true) {

…

• Introduction: From Software Language “Craft” to Software Language Engineering

• Compilation, MDE and Programming Languages

• Typing in MDE

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Motivations of SLE[Dagstuhl Seminar Proceedings: Language Engineering for Model-Driven Software

Development, 2004]

• Need for systematic approach of languages definition and tooling

• Go from “Software Language Craft” to Software Language Engineering

• Goals:

▫ Capture expert domains (DSLs)

▫ Process expert domains (analyses + transf.)

▫ Automate the path from expert domain to executable languages (compiler generation)

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Challenges

• Facilities for the definition of languages (abstract syntax, concrete syntax, semantic domain, semantic mapping)

• Suitable user interfaces

• Automate process whenever possible

• Coping with many languages

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• Introduction: From Software Language “Craft” to Software Language Engineering

• Compilation, MDE and Programming Languages

• Typing in MDE

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Cross-Fertilization of MDE and

Compilers Research Communities

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MDE

CompilationProgramming

Languages

Compilers Research

• Pros:

▫ Introduction of formal methods in languages

▫ Experience in program refactoring (e.g., tree rewritings)

▫ Experience in complex optimization problems (e.g., registers allocation, instructions selection, etc.)

• Cons:

▫ The number of transformations and their complexity increase:

Need for reuse and consistency

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General-Purpose Programming

Languages• Pros:

▫ Software languages formalization

Abstract syntax, concrete syntax, semantic domain, semantic mapping

▫ Type systems

• Cons:

▫ Difficult to use for a non-expert

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MDE

• System abstraction using domain specific models

• A model:

▫ Address one particular concern (security, business, UI…)

▫ Conforms to a metamodel

• A metamodel:

▫ Defines the concepts used in models (abstract syntax of a Domain Specific Modeling Language)

▫ Conforms to a metalanguage

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MDE

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The BPO has 154 agencies in 7 departments, employing 1470 persons. It has 341000 clients.…

Real world

Model BPO: Bank

RennesCentre:

Agency

RennesGare:

Agency

ClémentGuy:

Client: Account

: Account…

Metalanguage Class Reference

DSML

Bank: Class

Agency: Class Client: Class

Account: Classcontext Bank inv:

agencies.forall{ag|

accounts.forall{ac|

ac.owner.agency = ag

}

}

MDE

• Pros:

▫ Expertise on DSMLs definition and tooling:

Design by contract, generative approaches, metatools

• Cons:

▫ Lack of reuse

→Reuse of model operations through genericity

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MDE

CompilationProgramming

Languages

Compilers

generators

Genericity

in MDE

Automatic

parallelization

Genericity

Inheritance &

Polymorphism

Function

typing &

Higher order

V & V

Tree

rewriting

[CLU: reference manual, Liskov et al., 1981]

[Genericity in Java with virtual types, Thorup, 1997]

[The essence of functional programming, Wadler, 1992]

[Simula, an Algol-based simulation language, Dahl, 1966]

[A semantics of multiple inheritance, Cardelli, 1992]

[Subtyping is not a good "Match" for object-oriented languages, Bruce et al., 1997]

[Advanced compiler design and implementation, Muchnick, 1997]

[A brief history of just-in-time, Aycock, 1997]

[Eclipse Modeling Framework, Budinsky et al., 2003]

[GMF, http://www.eclipse.org/modeling/gmp/]

[Domain-specific modeling: enabling full code generation, Kelly et al., 2008]

[On Model Typing, Steel et al., 2007]

[Generic model refactorings, Moha et al., 2009]

[Templatable metamodels for semantic variation points, Cuccuru et al., 2007]

[Generic meta-modelling with concepts, templates and mixin layers, de Lara et al., 2010]

[Xtext, http://www.eclipse.org/Xtext/]

[ANTLR: A predicated-LL(k) parser generator, Parr et al., 1995]

[A pattern matching compiler for multiple target languages, Moreau et al., 2003]

[A structured approach to proving compiler optimizations based on dataflow analysis, Bertotet al., 2006]

[Genericity versus inheritance, Meyer, 1986]

[Typing in Model Management, Vignaga et al., 2009]

Domain

Specific

Modeling

Optimization

[Automatic Program Parallelization, Banerjeeet al, 1993]

Function

typing in

MDE Typing in MDE

• Introduction: From Software Language “Craft” to Software Language Engineering

• Compilation, MDE and Programming Languages

• Typing in MDE

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DSL2 DSL3

DSL4

DSL1

DSL2 DSL3

DSL4

DSL1

DSL2 DSL3

DSL4

DSL1

<<conformsTo>>

<<conformsTo>><<conformsTo>>

<<conformsTo>>

<<conformsTo>><<conformsTo>><<conformsTo>>

<<conformsTo>><<conformsTo>>

<<conformsTo>>

<<conformsTo>>

<<conformsTo>>

<<represents>>

<<represents>><<represents>>

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DSL2 DSL3

DSL4

DSL1

DSL2 DSL3

DSL4

DSL1

DSL2 DSL3

DSL4

DSL1 Model Typing

ModelType1

ModelType2 Model

Type3 ModelType4

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DSL2 DSL3

DSL4

DSL1

DSL2 DSL3

DSL4

DSL1

DSL2 DSL3

DSL4

DSL1 Model Typing

ModelType1

ModelType2 Model

Type3 ModelType4

Define a type system allowing substitutability of models, reusability of model operations and operations typing

Typing in MDE

• Type models with respect to:

▫ Their model elements

▫ Their model operations

• Type model operations with respect to:

▫ The type of their parameters (models or other transformations)

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Typing in MDE

• Type of a model:

MT = (C, O) s.t. C a set of classes and O a set of model operations

• Type of a model operation:

OT = T1 x … x Tn → Tr s.t. T1, …, Tn, Tn = MT or OT

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Type vs Metamodel vs Language

• Model typing with respect to:

▫ Their model elements

Looks like a metamodel

▫ Their model operations

Not so much

• Metamodel + Model operations = Abstract syntax + Semantics = Language

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Substitutability and Reuse

Genericity• Already existing approaches

• Parameterize languages with other languages

• Parameters have to match a structure on which operations are defined

[Generic model refactorings, Moha et al., 2009]

[Templatable metamodels for semantic variation points, Cuccuru et al., 2007]

[Generic meta-modelling with concepts, templates and mixin layers, de Lara et al., 2010]

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Substitutability and Reuse

Genericity• Operations defined on a structure

• Languages which match this structure can reuse the operations

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A

B C

Str1

A

B C

D

L1

var a: L1::A init L1::A.new

op<L1>(a)

operation op<T:Str1>(a: T::A)

is do

…

Substitutability and Reuse

Inheritance• Inherit structure and operations from “super-

languages”

• Define languages incrementally

• Need to define when a language is a subtype of an other

[On Model Typing, Steel et al., 2007]

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Substitutability and Reuse

Inheritance• Allow to define a new language

from existing one(s)

▫ Allow to reuse operations defined on “super-languages”

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var a2: L2::A init L2::A.new

a2.op()

A

B C

L1

A

B C

D

L2

<<inherits>>

class L1::A {

operation op() is do

…

Substitutability and Reuse

Inheritance• Allow to define a new language

from existing one(s)

▫ Allow to reuse operations defined on “super-languages”

▫ Allow a type hierarchy

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var a2: L2::A init L2::A.new

a2.op()

class L1::A {

operation op() is do

…

var a4: L4::A init L4::A.new

a4.op()

L1

L2 L3

L5L4

<<inherits>>

<<inherits>>

Covariance, Contravariance

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Mammal FoodMammal m := Mammal.new

Food f1 := Food.new

Food f2 = m.getFood()

m.setFood(f1)

food

Covariance, Contravariance

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Mammal FoodMammal m := Mammal.new

Food f1 := Food.new

Food f2 = m.getFood()

m.setFood(f1)

food

Covariance, Contravariance

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Mammal Food

Herbivore Plant

Mammal m := Mammal.new

Food f1 := Food.new

Food f2 = m.getFood()

m.setFood(f1)

Mammal m := Herbivore.new

Food f1 := Food.new

Food f2 = m.getFood()

m.setFood(f1)

food

food

Covariance, Contravariance

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Mammal Food

Herbivore Plant

Mammal m := Mammal.new

Food f1 := Food.new

Food f2 = m.getFood()

m.setFood(f1)

Mammal m := Herbivore.new

Food f1 := Food.new

Food f2 = m.getFood()

m.setFood(f1)

food

food

Covariance, Contravariance

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L1

A’

L2

A B

B’ C

Substitutability and Reuse

Adaptation• When languages are too different for inheritance

or genericity

• Differences may include:

▫ Renaming

▫ Gathering and separation of concepts

▫ …

• Need to know when an adaptation is possible

[IGraphAdapters@Cairn]

[An experiment of a MDE approach for the design of reusable DSL tools, Kerboeuf et al., IDM2011]

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Conclusion and Perspectives

• Multiplication of languages brings a need for Software Language Engineering

• MDE, compilers research and programming languages communities have experience in languages definition and tooling

• One of the challenges SLE must face is the need for reasoning on sets of languages

• We propose to define a type system for models, model operations, etc.

• And to validate this type system with real use cases from compilation community

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Questions, discussions ?

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