Editing Modelica (section)

==History==
The Modelica design effort was initiated in September 1996 by Hilding Elmqvist.
The goal was to develop an object-oriented language for modeling
of technical systems in order to reuse and exchange dynamic system models in
a standardized format. Modelica 1.0 is based on the
[[Doctor of Philosophy|PhD]] thesis<ref>{{cite web
| url=https://lup.lub.lu.se/search/ws/files/4602422/8570492.pdf
| title=A Structured Model Language for Large Continuous Systems.
}}</ref> of Hilding Elmqvist and on the experience with the modeling languages Allan,<ref>Jeandel A., Boudaud F.: [https://www.modelica.org/publications/papers/p303.pdf ''Physical System Modelling Languages: from ALLAN to Modelica''], Building Simulation'97, IBPSA Conference, Prague, September 8–10, 1997.</ref>
[[Dymola]], NMF<ref>{{cite web|url=http://www.equa.se/dncenter/handbook.pdf |author=Per Sahlin|title= NMF HANDBOOK. An Introduction to the Neutral Model Format. NMF version 3.02. |date=November 1996}}</ref> 
ObjectMath,<ref>{{cite web|url=http://www.ida.liu.se/labs/pelab/omath/|title=ObjectMath Home Page}}</ref> 
Omola,<ref>S.E. Mattsson, M. Andersson and K.J..Aström: Object-oriented modeling and simulation. In: Linkens, ed., CAD for Control Systems (Marcel Dekker, 1993) pp. 31-69.</ref> 
SIDOPS+,<ref>{{cite journal|title=CiteSeerX — Modeling Mechatronic Systems Using The Sidops+ Language| year=1997 | pages=301–306 |citeseerx = 10.1.1.56.4266}}</ref> and Smile.<ref>Ernst T., Jähnichen S., Klose M.: [https://www.modelica.org/publications/papers/imacs97.pdf ''Object-Oriented Physical Systems Modeling, Modelica, and the Smile/M Simulation Environment'']. 15th IMACS World Congress on Scientific Computation, Modelling and Applied Mathematics, Berlin, August 24–29, 1997.</ref>  Hilding Elmqvist is the key architect of Modelica, but many other people have contributed as well (see appendix E in the Modelica specification<ref name="3.5spec"/>). In September 1997, version 1.0 of the Modelica specification was released which was the basis for a prototype implementation within the commercial Dymola software system. In year 2000, the non-profit Modelica Association was formed to manage the continually evolving Modelica language and the development of the free Modelica Standard Library. In the same year, the usage of Modelica in industrial applications started.

This table presents the timeline of the Modelica specification history:<ref>{{cite web
| url=http://www.modelica.org/news_items/documents
| title=Documents
| publisher=Modelica Association
| access-date=2009-10-11}}</ref>
{| class="wikitable"
|-
!width=30| Release
!width=110| Release Date
!width=550| Highlights
|-
|1.0||1997, September||First version to model continuous dynamic systems.
|-
|1.1||1998, December||Language elements to model discrete systems (pre, when)
|-
|1.2||1999, June||Interface to C and Fortran, inner/outer for global variables, refined semantics of event handling
|-
|1.3||1999, December||Improved semantics for inner/outer connections, protected elements, array expressions.
|-
|1.4||2000, December||Removed declare-before-use rule, refined package concept, refined when-clause
|-
|2.0||2002, July||Initialization of models, standardization of graphical appearance, functions with mixed positional and named arguments, record constructor, enumerations
|-
|2.1||2004, March||Overdetermined connector to model 3-dim. mechanical systems, enhanced redeclaration of submodels, array and array indices of enumerations
|-
|2.2||2005, February||Expandable connector to model signal buses, conditional component declarations, arrays with dynamic size changes in functions
|-
|3.0||2007, September||Clean-up version: specification newly written, type system and graphical appearance refined, language flaws fixed, balanced model concept to detect model errors in a much better way
|-
|3.1||2009, May||Stream connector to handle bi-directional flow of fluid, operator overloading, mapping model parts to execution environments (for use in [[embedded systems]])
|-
|3.2||2010, March||Improved initialization with homotopy method, functions as formal inputs to functions, [[Unicode]] support, access control to protect [[Intellectual property|IP]], improved support of object libraries
|-
|3.3||2012, May||Added language elements to describe periodic and non-periodic synchronous controllers based on clocked equations, as well as synchronous state machines.
|-
|3.4||2017, April||Automatic conversion of models. Many minor improvements
|-
|3.5||2021, February||Annotations for predefined plots. Change of specification format, with many editorial changes. Clarifications to synchronous language elements and state machines. Many minor clarifications to functions, model conversions, and several other parts of the specification. 
|-
|3.6
|2023, March
|Removing modifiers with <code>break</code> and selective model extensions. Multilingual support to present Modelica libraries in multiple languages.
|-
|}