Semantics for DSL

Group Members: Ritu Arora, Diyang Chu, Zekai Demirezen,

Jeff Gray, Jacob Gulotta, Luis Pedro, Arturo Sanchez, Greg Sullivan,Ximing Yu

What do semantics mean for a modeling language?

• The details about the concepts that are in the mind of the domain-experts should be written formally.

• The semantics represent the meaning of the phrases and sentences that the domain expert may express.– Box: Represents a State? Class? Foo?

Why do we want a clear and precise representation of model semantics?

• A clean formalism enables reasoning about desired properties– Analysis

• deadlock analysis • ambiguity? • consistency?

• Generation of associated tools from the semantics definition– Code generators– Debugging tools– Test cases– Visualization of execution/animation

How to define the semantics for DSL?

• The state of the art represents model semantics at a low-level– Defined in model interpreters

• Emerging approaches– …

Domain-Specific Semantics• Are the semantics of the DSL actually domain-

specific? – Lack of a standard for defining semantics for DSLs– The notion of static semantics is easy and already

defined in many tools; dynamic semantics represent the clear challenge

– Proving properties of a GPL is challenging, but should be easier for DSLs (e.g., behavioral preservation of transformations, ambiguity)

– Domain-specific properties • would be helpful if semantics are defined in a formal,

declarative language

Concerns for defining DSLs

• Concern: – separate syntax & semantics– define roles (language engineer, end-user)– define appropriate semantic domain• Document object model• Abstract state machine

Current Approaches 1

• Graph rewriting– ATOM3 (multi -formalism approach)

• Any thing that can be defined as a model can be used as a meta-model

• Subset of Python, OCL to define pre and post conditions• Used for simulation purposes

• Combine Syntax and Semantic definition formalisms in one language.– Kermeta

• Extends EMOF to enable behavior definitions of meta-elements

Current Approaches 2

• Semantic Anchoring through transformation• Mapping meta elements in to semantic elements in

another formalism with well-defined semantics• Example

– Finite State Machine can be used along to define the semantics of the DSL

– Transformation view on the next slide

M3

M2

M1

myDSLMetamodel

myDSL.dsl

EBNFEBNF

myDSL.gGrammar

myDSL Model

KM3

myDSL Technical Space Model-Driven Engineering Technical Space

FSMDSLMetamodel

FSMDSL.gGrammar

FSM.fsmdslExtractionInjection

Legend:M1 = Terminal model level M2 = Metamodel levelM3 = Meta- metamodel level

Anchor FSM Technical Space

myDSL to FSMDSLTransformation

Conforms to

Conforms to

Conforms to

Conforms to

Conforms to

Conforms to

Conforms to

FSMDSL Model

Operational Semantics