Kermeta is a modeling and programming language for metamodel engineering.
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The Kermeta language was initiated by Franck Fleurey in 2005 within the Triskell team of IRISA (gathering researchers of the INRIA, CNRS, INSA and the University of Rennes 1).
The Kermeta language borrows concepts from languages such MOF, OCL and QVT, but also from BasicMTL, a model transformation language implemented in 2004 in the Triskell team by D. Vojtisek and F. Fondement. It is also inspired by the previous experience on MTL, the first transformation language created by Triskell, and by the Xion action language for UML.
The name Kermeta is an abbreviation for "Kernel Metamodeling" and reflects the fact that the language is conceived as a core for (meta-)modeling. The Breton language consonance of this name is an intentional reflection of the Triskell team's location in Britanny.
Kermeta, and its execution platform under Eclipse is currently available under its version 1.4.1. It is open-source, under the Eclipse Public License.
Kermeta is a modeling and aspect oriented programming language. Its underlying metamodel conforms to the EMOF standard. It is designed to write programs which are also models, to write transformations of models (programs that transform a model into another), to write constraints on these models, and to execute them 1). The goal of this model approach is to bring an additional level of abstraction on top of the "object" level and thus to see a given system like a set of concepts (and instances of concepts) that form an explicitly coherent whole, which one will call a model.
Kermeta thus brings:
The main characteristics of the Kermeta language are :
The curious reader will find further information on the Kermeta website.
package fsm;
require kermeta
using kermeta::standard
class FSM
{
attribute ownedState : set State[0..*]#owningFSM
reference initialState : State[1..1]
reference currentState : State
/**
* Print the FSM on the standard output
*/
operation printFSM() is do
self.ownedState.each
{ s |
stdio.writeln("State : " + s.name)
s.outgoingTransition.each
{ t |
stdio.writeln(" Transition : " + t.source.name +
"-(" + t.input + "/" + t.output + ")->" + t.target.name)
}
}
end
}
class State {
attribute name : String
reference owningFSM : FSM#ownedState
attribute outgoingTransition : set Transition[0..*]#source
reference incomingTransition : set Transition[0..*]#target
operation step(c : String) : String is do
// Get the valid transitions
var validTransitions : Collection<Transition>
validTransitions := outgoingTransition.select { t | t.input.equals(c) }
// Check if there is one and only one valid transition
if validTransitions.empty then raise "No Transition!" end
if validTransitions.size > 1 then raise "Non Determinism" end
// fire the transition
result := validTransitions.one.fire
end
}
class Transition
{
reference source : State[1..1]#outgoingTransition
reference target : State[1..1]#incomingTransition
attribute output : String
attribute input : String
operation fire() : String is do
// update FSM current state
source.owningFSM.currentState := target
result := output
end
}