The document summarizes a talk on live modeling given by Benoit Combemale at a LangDev meetup at Amazon. Live modeling brings immediate feedback and direct manipulation capabilities to modeling environments. It allows users to see how changes to a model impact its runtime state or execution trace. Live modeling has various uses across different domains and can enhance modeling tools. The talk explored live modeling challenges and approaches from a language engineering perspective, with the goal of integrating these capabilities into domain-specific languages.

1. LANGDEV MEETUP, MARCH 21-22, 2019, AMSTERDAM, NL
BREATHE LIFE INTO YOUR IDE
BENOIT COMBEMALE
PROFESSOR, UNIV. TOULOUSE, FRANCE
HTTP://COMBEMALE.FR
BENOIT.COMBEMALE@IRIT.FR
@BCOMBEMALE
BENOIT COMBEMALE
PROFESSOR, UNIV. TOULOUSE & INRIA, FRANCE
HTTP://COMBEMALE.FR
BENOIT.COMBEMALE@INRIA.FR
@BCOMBEMALE

2. LangDev Meetup @ Amazon
Benoit Combemale, March, 2019
Model Execution: Why Should I care?
▸ Various engineering: software engineering, systems
engineering, enterprise architecture, scientific
modeling...
▸ Various domains: Business Processes, Orchestrations,
Functional chains, Activities, Protocols, Scenarios...
▸ Various objectives: dynamic analysis, design-space
exploration, tradeoff analysis, models@runtime
breathe life into your
(domain-specific) behavioral models

3. LangDev Meetup @ Amazon
Benoit Combemale, March, 2019
Model Execution: Main Challenges
• A behavioral model is a structural description of an intended
behavior
• Challenge: how to support modelers in bridging the gap between
the model structure and the corresponding behavior, over the
time
• (some) Expected facilities ?
• debug the execution results (i.e. runtime state) instead of the model itself
• consider the dimension of time natively (if not already reified in the
model, e.g. message sequence charts)
• bridge the gap between the model execution and its interpretation within
a particular domain (e.g., moldable debugger [Chis et al.])
• ease the understanding of the impact of a model change
3

4. LangDev Meetup @ Amazon
Benoit Combemale, March, 2019
Model Execution: Main Challenges
• A behavioral model is a structural description of an intended
behavior
• Challenge: how to support modelers in bridging the gap between
the model structure and the corresponding behavior, over the
time
• (some) Expected facilities ?
• debug the execution results (i.e. runtime state) instead of the model itself
• consider the dimension of time natively (if not already reified in the
model, e.g. message sequence charts)
• bridge the gap between the model execution and its interpretation within
a particular domain (e.g., moldable debugger [Chis et al.])
• ease the understanding of the impact of a model change
4

5. LangDev Meetup @ Amazon
Benoit Combemale, March, 2019
The GEMOC Studio
5
Model Animator
Operational Semantics
(executable)
Model
(executable)
Modeling
Language
Metamodeling
LanguagesKermeta Ecore
aModel
trace
manager,
timeline,
control
panel,
omniscient
debugger
Concrete Syntax
Graphical
representation
Sirius
Graphical
representation
DSA Executor
Interpreter
Diagram
Model Editor
Diagram
Domain-Specific
Actions
Execution
Functions
Execution
Data
Abstract Syntax
Domain Model
(Metamodel)
Legend
code generation
<<dependsOn>>
<<conformsTo>>
ALE
https://eclipse.org/gemoc

6. ALE
LangDev Meetup @ Amazon
Benoit Combemale, March, 2019 6
▸ An Action Language for EMF [EclipseCon’17]
▸ To complement an Ecore metamodel with Runtime Data and Eoperation impl.
▸ To define any Interpreter, compiler, model transformation, analysis tools…
▸ ALE extends AQL (Acceleo Query Language)
▸ Provides side effects and additional complex control structures
▸ Main characteristics:
▸ Interpreted (though, a compiler also exist)
▸ Static typing, type inference
▸ Open class support
▸ Contributed to Eclipse EcoreTools
▸ Define behavior over an Ecore metamodel
▸ Modular specification (thanks to Sirius layers and open class)
▸ Integrated into the Eclipse GEMOC Studio
▸ Binding to the debug UI, control panel and trace manager
Coulon’s PhD,
Obeo & Inria
https://github.com/gemoc/ale-lang
http://gemoc.org/ale-lang
open class arduino.If {
@step
def void execute() {
if (self.condition.evaluate()) {
self.block.execute();
} else {
if (self.elseBlock != null) {
self.elseBlock.execute();
}
}
}
}
LANGDEV’18

7. SiriusAnimator
Animator
LangDev Meetup @ Amazon
Benoit Combemale, March, 2019
LANGDEV’18

8. LangDev Meetup @ Amazon
Benoit Combemale, March, 2019
https://github.com/gemoc/arduinomodeling
ArduinoDebugger

9. LangDev Meetup @ Amazon
Benoit Combemale, March, 2019
ActivityDiagramDebugger
https://github.com/gemoc/activitydiagram
9

10. LangDev Meetup @ Amazon
Benoit Combemale, March, 2019
PacMan!
10

11. - 11
HIGH PERFORMANCE COMPUTING
in collaboration with
Fostering metamodels and grammars within a dedicated environment for HPC: the NabLab environment
Benoît Lelandais, Marie-Pierre Oudot, Benoît Combemale
In International Conference on Software Language Engineering (SLE), 2018

12. - 12
HIGH PERFORMANCE COMPUTING
in collaboration with

13. - 13
HIGH PERFORMANCE COMPUTING
in collaboration with
in collaboration with
Current technical limitations:
• technical integration of Monaco, JupyterLab and the
language server
• Integration of Monaco in notebook’s cells
• syntax highlighting not supported by LSP
• collaborative editing
Ongoing work:
• automatic generation of REPL language servers
• graphical representation based on Sirius on the web

14. - 14
WATER FLOOD PREDICTION
in collaboration with
A. Cheron, Master Thesis, 2017

15. - 15
WATER FLOOD PREDICTION
in collaboration with
J. Sallou, PhD, 2018-…
Description / documentation of
the simulation process
Code of one step of the
simulation process
Visualization of the simulation
results

16. LangDev Meetup @ Amazon
Benoit Combemale, March, 2019
Towards Live Modeling
• Model execution and debugging ease the
understanding of the actual behavior that
describes a given model
• But are limited for understanding the impact of a
model change in the resulting behavior
17

17. LangDev Meetup @ Amazon
Benoit Combemale, March, 2019
Some Scenarios for Live Modeling
Live coding
Design Space
Exploration
Tradeoff analysis &
Decision making
Arts
Computational
Sciences
Engineering
Digital twins

18. Rationales for Live Modeling
▸ Focus on executable modeling, where:
▸ the model(s) gathers the data and the behavior
▸ the model(s) conforms to a gray box operational semantics
▸ Live modeling should support the following main scenarios:
▸ Immediate feedback: changes at runtime of the model structure
(data or behavior)
▸ Direct manipulation: changes at runtime of the model state
▸ Additional scenarios: change at runtime of the input scenario, the
language semantics…
LangDev Meetup @ Amazon
Benoit Combemale, March, 2019 19

19. Live Modeling: Towards a Conceptual Model
▸3 dimensions of abstraction:
▸ structure (data/behavior)
▸ state
▸ time
▸Immediately observe the impact on the model state
▸ surimposition on top of the running model
▸ through specific views of the model state, and over the time
LangDev Meetup @ Amazon
Benoit Combemale, March, 2019 20
(BretVictor,http://worrydream.com)

20. Live Modeling: Processes
LangDev Meetup @ Amazon
Benoit Combemale, March, 2019 21
GEMOC Engine
(executable)
Model
(executable)
Modeling
Language
Metamodeling
Languages
ALE Ecore
MyDSML
.ale
MyDSML
.ecore
aRunningModel
VM
Model
State
AST
aRunningModel
Model
State
AST
Change on the model (AST):
• Compute the delta
• Check delta validity (e.g.,
conformity)
• Reconcile delta (i.e., compute
how to apply it to the static
model, and apply it)
• Reflect the syntactic delta in
the model state
Change on the model state:
• Compute the delta
• Check delta validity (e.g.,
conformity)
• Reconcile delta
NB: checking vs. reconciliation?

21. Breathe life into your…
LangDev Meetup @ Amazon
Benoit Combemale, March, 2019 22
▸ Operational Semantics
▸ Static introduction
with open classes
▸ Kermeta v1, v2, v3 and
ALE
metamodel
model execution
designer
animation and debug
IDE
live modeling
2005 2012 2018
▸ Execution trace
management
▸ Forward/backard step-
by-step execution
▸ GEMOC Studio
▸ Immediate feedback &
direct manipulation
▸ Reconciliation operators
▸ Extending LSP, GSP &
DAP
Pierre-Alain Muller, Franck Fleurey,
Jean-Marc Jézéquel: Weaving
Executability into Object-Oriented Meta-
languages. MoDELS 2005: 264-278
Erwan Bousse, Thomas Degueule, Didier
Vojtisek, Tanja Mayerhofer, Julien DeAntoni,
Benoît Combemale: Execution framework of the
GEMOC studio (tool demo). SLE 2016: 84-89
Jean-Marc Jézéquel, Benoît Combemale, Olivier Barais, Martin
Monperrus, François Fouquet: Mashup of metalanguages and
its implementation in the Kermeta language workbench.
Software and System Modeling 14(2): 905-920 (2015) …

22. Live Modeling: (some) Open Challenges
▸Model change:
▸ what to open to modification in the model and the model state?
▸ explicit language interfaces (similarly to debugging)
▸ how to ensure the validity of the changes?
▸Reconciliation operators:
▸ Pattern, techniques and heuristics for reconciliation operators?
▸ when can we reconcile or restart?
▸Impact visualization:
▸ what to open to visualization?
▸ Live modeling over related, heterogeneous, models
LangDev Meetup @ Amazon
Benoit Combemale, March, 2019 23

23. Breathe life into your IDE
Abstract.
Live modeling brings facilities to enhance modeling environments with immediate feedback
(from changes on the model to the runtime state, and possibly the execution trace), and direct
manipulation (from changes on the runtime state to the model). Such facilities are helpful in
tuning specific solutions, exploring design spaces, or performing tradeoff analysis. Hence, live
modeling have a growing appeal among very different stakeholders, ranging from software
and systems engineers, to scientists, decision makers, artists or the general public.
After a brief introduction of several case studies illustrating the different scenarios expected by
language users, I explore in this talk live modeling from the point of view of a language
engineer. I describe a general approach to bring this new concern in the specification of
domain-specific languages. Then I explore the underlying challenges, review the current
initiatives, and propose a research roadmap.
As take away messages, the audience will learn about live modeling and how to support it in
the development of domain-specific languages. A description of the current initiatives, the
open challenges and an associated research roadmap is given to help the community in future
investigations.
LangDev Meetup @ Amazon
Benoit Combemale, March, 2019