Contributions to Meta-Modeling
Tools and Methods
Adrian Pop
Programming Environments Laboratory
Outline
ƒ Product Design Environments
ƒ Meta-Modeling
ƒ Modelica Meta-Model
ƒ Invasive Composition of Modelica
ƒ Model-driven Product Design using Modelica
ƒ Meta-Programming
ƒ Debugging of Natural Semantics Specifications
ƒ Conclusions and Future Work
2
Domain Specific Environments
Gearbox
Complex
physical
products
demultiplex
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Difficult
manual
process
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Compilers
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Design
environments
Model editors
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S
Debuggers
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Simulators
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Research Objectives
ƒ Context
ƒ Model-driven product design environments
ƒ Modeling and simulation
ƒ Modelica Framework
ƒ Objective
ƒ Efficient development of such environments
ƒ Meta-modeling and meta-programming
tools and methods
4
Modelica
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Declarative language
Multi-domain modeling
Everything is a class
Visual component
programming
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ƒ
ƒ
ƒ
demultiplex
ƒ Modelica
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ƒ Modelica Association
ƒ http://www.modelica.org
5
Meta-Modeling
World
The Modeling Space
Meta-Meta Model
Meta Model
Model
Physical system
6
Meta-Programming
MetaModelica and
Natural Semantics
Specification
formalisms
Abstraction
Meta- Meta Model
Meta-Model1
Model1
Model2
Meta-Model2
...
Model3
Modelica
language
specifications
Modelica
models
Meta-programming:
transformation
7
Outline
ƒ Product Design Environments
ƒ Meta-Modeling
ƒ Modelica Meta-Model
ƒ Purpose
ƒ Definition and Applications
ƒ Problems
ƒ Invasive Composition of Modelica
ƒ Model-driven Product Design using Modelica
ƒ Meta-Programming
ƒ Debugging of Natural Semantics Specifications
ƒ Conclusions and Future Work
8
Modelica Community
ƒ Fast growing model base
ƒ Needs flexible stand-alone tools for:
ƒ
ƒ
ƒ
ƒ
ƒ
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analysis of models (checkers and validators)
pretty printing (un-parsing)
interchange with other modeling languages
query and transformation of models
imposing code style guidelines
documentation generation (Html, SVG, MathML, etc)
Need of better support:
ƒ easy access to the language structure
ƒ interoperability, flexibility
9
Modelica Meta-Model
ƒ Store the structure (Abstract Syntax) of the
Modelica language using an alternative
representation
ƒ Create tools that use this alternative
representation
ƒ The alternative representation should
ƒ be easy accessible from any programming language
ƒ be easy to transform, query and manipulate
ƒ Support validation through a meta-model
XML has all these properties
10
ModelicaXML Representation
Modelica
code
Modelica Parser
Modelica
XML
class Test "comment"
modelicaxml
Real x;
Real xdot;
definition
equation
xdot = der(x);
component
end Test;
equation
component
<modelicaxml>
<definition ident= "Test"
comment="comment">
<component ident="x" type="Real"
visibility="public" />
<component ident="xdot" type="Real"
visibility="public" />
<equation>...</equation>
</definition>
</modelicaxml>
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Validation using Modelica Meta-Model
ƒ provides a vocabulary for
creating models
ƒ imposes constraints over
the model structure
ƒ is used to validate models
modelicaxml
definition
equation
component
equation
12
ModelicaXML Representation - Applications
ƒ Applications of ModelicaXML Representation
ƒ
ƒ
ƒ
ƒ
ƒ
Interoperability and transformation
Easy access from any programming language
Query facilities
Documentation generation
Validation of models using the meta-model
13
Outline
ƒ Product Design Environments
ƒ Meta-Modeling
ƒ Modelica Meta-Model
ƒ Invasive Composition of Modelica
ƒ Invasive Software Composition
ƒ Modelica Composition
ƒ Applications
ƒ Model-driven Product Design using Modelica
ƒ Meta-Programming
ƒ Debugging of Natural Semantics Specifications
ƒ Conclusions and Future Work
14
Invasive Software Composition
ƒ Composition of black
box components
ƒ Hard to adapt
components to context
ƒ Generates possibly
inefficient systems
ƒ Invasive Software Composition
ƒ Composition system can see inside the components
ƒ Components are hidden behind a composition interface
Components are composed using a composition language
ƒ Components can be configured by changing their actual
code at variation points (boxes and hooks) defined by the
component model
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Invasive Composition for Modelica
The Compost System
Composition
Programs
ModelicaComponent Model
Composed
System
ModelicaXML
Template
Components
Defines
ƒModelicaBoxes
ƒModelicaHooks
Modelica Models
ƒ The benefit of Invasive Modelica Composition
ƒ
ƒ
ƒ
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Generation of different version of models from product specifications
Automatic configuration of models using external sources
Fine grain support for library developers
Refactoring, reverse engineering, etc
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Modelica Component Model – Boxes
XMLBox
Defines a set of templates
for each language structure
ModelicaXMLBox
ModelicaContainer
0..*
ModelicaElement
ModelicaComponent
ModelicaClass
ModelicaType
ModelicaModel
ModelicaPackage
ModelicaEquationSection
ModelicaRecord
ModelicaFunction
ModelicaAlgorithmSection
ModelicaBlock
ModelicaConnector
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Example Box Hierarchy
<definition ident="Engine" restriction="class">
<component visibility="public” variability="parameter"
type="Integer" ident="cylinders">
<modification_equals>
<integer_literal value="4"/>
</modification_equals>
</component>
<component visibility="public" type="Cylinder" ident="c">
<array_subscripts>
<component_reference ident="cylinders"/>
</array_subscripts>
</component>
</definition>
class Engine
ModelicaClass
ModelicaComponent
parameter Integer
cylinders = 4;
Cylinder c[cylinders];
end Engine;
ModelicaComponent
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Modelica Component Model – Hooks
Hook
DeclaredHook
ImplicitHook
XMLImplicitHook
XMLDeclaredHook
ModelicaModifierHook
ModelicaParameterHook
ModelicaRealHook
Other Modelica Hooks
ModelicaIntegerHook
ModelicaStringHook
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Example: Hooks
<component visibility="public” variability="parameter"
type="Integer" ident="cylinders">
<modification_equals>
<integer_literal value="4"/>
ModelicaParameterHook
</modification_equals>
name
</component>
parameter Integer
cylinders = 4;
value
<definition ident=”NewEngine" restriction="class">
<extends type=”Engine”>
class NewEngine
....
extends Engine;
</definition>
....
end NewEngine;
<definition ident=”Engine” restriction="class">
<extract>
<component>..</component> ...
</extract>
</definition>
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Composition Programs: Mixin
ModelicaCompositionSystem cs =
new ModelicaCompositionSystem();
ModelicaClass resultBox =
cs.createModelicaClass(”Result.mo.xml”);
ModelicaClass firstMixin =
cs.createModelicaClass(”Class1.mo.xml”);
ModelicaClass secondBox =
cs.createModelicaClass(”Class2.mo.xml”);
resultBox.mixin(firstMixin);
resultBox.mixin(secondMixin);
resultBox.print();
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Outline
ƒ Product Design Environments
ƒ Meta-Modeling
ƒ Modelica Meta-Model
ƒ Invasive Composition of Modelica
ƒ Model-driven Product Design using Modelica
ƒ Product Design based on Function-Means decomposition
ƒ Integration with Modelica for Early Design Validation
ƒ Meta-Programming
ƒ Debugging of Natural Semantics Specifications
ƒ Conclusions and Future Work
22
Model-Driven Product Design
ƒ Product design
ƒ product concept modeling and evaluation
ƒ physical modeling and simulation
ƒ Need for integration of
ƒ conceptual modeling tools and
ƒ modeling and simulation tools
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Example: design phases of an Aircraft Product
ƒ Aircraft conceptual model in FMDesign
ƒ decomposition of the aircraft into functions and
means
ƒ mapping between means and Modelica
simulation components
ƒ simulation of various design choices
ƒ choosing the best design choice using the
simulation results
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FMDesign – Conceptual Product Design
Courtesy of Olof Johansson. Developed in cooperation with Peter Krus, IKP
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Simulation Components for an Aircraft Product
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A Framework for Product Design
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Framework Integration Tools
ƒ ModelicaDB – Modelica Model Database
ƒ is populated with simulation models by importing their
ModelicaXML representation
ƒ is a simulation models repository
ƒ provides search and organizational features
ƒ flexibility, scalability and collaborative development
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Framework Integration Tools (cont)
ƒ The Selection and Configuration Tool
ƒ searches ModelicaDB for simulation models
ƒ calls modeling tools for creating/editing simulation
models
ƒ configuration dialogs for selected simulation models
for specific means implementation
ƒ The Automatic Model Generator Tool
ƒ generates Modelica models of the product
ƒ calls external simulation tools for simulation
ƒ feeds the simulation results back to the designer to
help him/her choose the best design choice
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Architecture Overview
F = Function
M = Means
Requirements
Database
Product Concept
Design Tool
(FMDESIGN)
Reference Links
Means
Evaluations
Product Concept Design
Database
F1
M1a
F1a.1
F1a.2
M1b
Operation
Cases
M1c
Engineering
Design
System X
F1a.3
Selection and Configuration
Tool
Simulation
Evaluation
Optimisation
Automatic
Model
Generator
Tool
ModelicaXML
Generated
Models
Modelica
Simulation
Source code
Modelica Model
Database
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Outline
ƒ Product Design Environments
ƒ Meta-Modeling
ƒ Modelica Meta-Model
ƒ Invasive Composition of Modelica
ƒ Model-driven Product Design using Modelica
ƒ Meta-Programming
ƒ Debugging of Natural Semantics Specifications
ƒ Natural Semantics and Relational Meta-Language
ƒ Debugging framework
ƒ Conclusions and Future Work
31
ModelicaXML Representation - Problems
ƒ Problems
ƒ XML can only express syntax
ƒ No easy way to automatically handle semantics
ƒ Possible solutions when expressing semantics
ƒ use markup languages developed by Semantic Web to
express some of the Modelica semantics
ƒ use other formalisms like Natural Semantics
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Meta-Programming
ƒ Meta-Programs
ƒ programs that manipulate other programs
ƒ Natural Semantics, a formalism widely used for
specification of programming language aspects
ƒ type systems
ƒ static, dynamic and translational semantics
ƒ few implementations in real systems
ƒ Relational Meta-Language (RML)
ƒ a system for generating efficient executable code from
Natural Semantics specifications
ƒ fast learning curve, used in teaching and specification
of languages such as: Java, Modelica, MiniML, etc.
ƒ previously no support for debugging
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Natural Semantics vs. Relational Meta-Language
Natural Semantics formalism
integers:
v ∈ Int
expressions (abstract syntax):
e ∈ Exp ::= v
| e1 + e 2
| e1 − e 2
| e1* e 2
| e1 / e 2
| −e
(1) v ⇒ v
(2)
Relational Meta-Language
module exp1:
(* Abstract syntax of language Exp1 *)
datatype Exp = INTconst of int
| ADDop of Exp * Exp
| SUBop of Exp * Exp
| MULop of Exp * Exp
| DIVop of Exp * Exp
| NEGop of Exp
relation eval: Exp => int
end
relation eval: Exp => int =
axiom eval(INTconst(ival)) => ival
rule eval(e1) => v1 & eval(e2) => v2 & v1 + v2 => v3
----------------------------------------------eval( ADDop(e1, e2) ) => v3
rule eval(e1) => v1 & eval(e2) => v2 & v1 - v2 => v3
----------------------------------------------eval( SUBop(e1, e2) ) => v3
...
end (* eval *)
e 1⇒ v 1 e 2 ⇒ v 2 v1+v2 ⇒ v3
e 1+ e 2 ⇒ v 3
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The Need for RML Debugging
ƒ Facilitate language learning
ƒ run, stop and inspect features
ƒ Large specifications are hard to debug
ƒ Example: OpenModelica compiler
ƒ 43 packages
ƒ 57083 lines of code and counting
ƒ 4054 functions
ƒ 132 data structures
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Debugger Implementation - Overview
module Dump
with “absyn.rml”
relation dump: Absyn.Program => ()
...
RML
Compiler
External
Program
Database
RML Data Browser
ANSI-C
RML Debugging
Emacs Mode
Linking with the
RML
debugging runtime
Executable
with
Debugging
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Debugger Implementation - Instrumentation
(* Evaluation semantics of Exp1 *)
relation eval: Exp => int =
axiom eval(INTconst(ival)) => ival
rule
eval(e1) => v1 &
eval(e2) => v2 &
v1 + v2 => v3
--------------------------eval( ADDop(e1, e2) ) => v3
(* Evaluation semantics of Exp1 *)
relation eval: Exp => int =
axiom eval(INTconst(ival)) => ival
rule
...
end (* eval *)
) &
RML.debug_push_in01("e1",e1) &
RML.debug(...) &
eval(e1) => (v1) &
RML.debug_push_out01("v1",v1) &
RML.debug_push_in01("e2",e2) &
RML.debug(...) => () &
eval(e2) => (v2) &
RML.debug_push_out01("v2",v2) &
RML.debug_push_in02("v1",v1,"v2",v2
RML.debug(...) &
RML.int_add(v1,v2) => (v3)
-----------------------------------
---eval(ADDop(e1,e2)) => (v3)
...
end (* eval *)
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Debugger Functionality (1)
Breakpoints
Stepping and Running
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Debugger Functionality (2)
ƒ Additional functionality
ƒ viewing status information
ƒ printing backtrace
information (stack trace)
ƒ printing call chain
ƒ setting debugger defaults
ƒ getting help
Examining data
ƒprinting variables
ƒsending variables to an
external browser
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Browser for RML Data Structures (1)
Variable value
inspection
Current Execution
Point
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Browser for RML Data Structures (2)
Data structure
browsing
Data structure
definition
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Conclusions
ƒ Meta-Modeling
ƒ Alternative Modelica Representation (ModelicaXML)
ƒ Conform to a Meta-Model for Modelica
ƒ Invasive Composition of Modelica
ƒ Model configuration and adaptation
ƒ Based on ModelicaXML and a Component Model for Modelica
ƒ Model-driven Product Design using Modelica
ƒ Integration of conceptual product modeling with modeling and
simulation tools
ƒ Flexibility, scalability
ƒ Uses ModelicaXML as a middleware
ƒ Meta-Programming
ƒ Debugging of Natural Semantics Specifications
ƒ large specification debugging (OpenModelica Compiler)
ƒ Debugging of MetaModelica models
42
Future Work
ƒ Meta-Modelica Compiler
ƒ Unified equation-based meta-modeling and meta-programming
specification language for both:
ƒ language models and physical system models
ƒ Work in progress, first version based on RML
ƒ Compilation of a Modelica extended with features such as:
ƒ pattern matching, tree structures, lists, tuples, etc.
ƒ More Meta-Modeling capabilities (constraints on models, etc)
ƒ Improvement of the debugging framework
ƒ Experimenting with an Eclipse-IDE that integrates these tools
ƒ Add new features to the Relational Meta-Language system
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End
Thank you!
Questions?
44
Resources
ƒ ModelicaXML and ModelicaOWL
ƒ http://www.ida.liu.se/~adrpo/modelica/xml
ƒ http://www.ida.liu.se/~adrpo/modelica/owl
ƒ The Invasive Composition System Compost
ƒ http://www.the-compost-system.org/
ƒ Relational Meta-Language (RML)
ƒ http://www.ida.liu.se/~pelab/rml
ƒ MetaModelica Compiler (MMC)
ƒ http://www.ida.liu.se/~adrpo/mmc
ƒ Licentiate Thesis
ƒ http://www.ida.liu.se/~adrpo/lic
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Thesis Structure
Meta-Modeling
RML Specification of Modelica
Thesis Structure
Chapter 1 – Introduction
Chapter 2 – ModelicaXML, the Meta-Model of Modelica
Chapter 3 – Invasive Composition of Modelica using COMPOST and ModelicaXML
Chapter 4 – Integration of Product Design Tools with Modeling and Simulation Tools
Chapter 5 – Comparison between Modelica Libraries and Ontologies
Chapter 6 – Debugging framework for RML
Chapter 7 – Related research contributions
Chapter 6
RML
System
Debugging
Product Concept
C Code
Product
Design
Tools
C
Compiler
Composition
Program
Chapter 4
Modelica Database
COMPOST
Open
Modelica
Compiler
Chapter 3
Virtual Product
XML
Tools
ModelicaXML
C Code
Chapter 2
Modelica
Parser
Modelica
C
Compiler
Modeling
and
Simulation
Tools
Modelica
Simulation
Meta-Programming
46