TRADUCTION D4UN TEXTE EN ANGLAIS

MERCI DE ME TRADUIRE CE TEXTE QUI PARLE D'OCL (LANGAGE DE CONTRAINTE)

For example, OCL allows postconditions like self.attr1 = self.attr2, but does not specify whether this means that
attr1 has changed, attr2 has changed or both or neither of them have changed. To interpret such statements LEIRIOS
Test Designer™ distinguishes to kinds of predicates, active ones and passive ones, based on the desired semantics of
each OCL operator. For example, the condition part of an if-then-else is passive, while the then and else parts are active
(provided that whole if-then-else itself is active). Preconditions and transition guards are always passive. In P1 implies P2,
P1 is passive and P2 is active, in E->select(P), P is passive, while in E->forall(P) and E->exists(P), P is active. LEIRIOS
Test Designer™ assumes that variables that are not mentioned at all in a postcondition do not change, and that equality
should be interpreted as an assignment only in certain active contexts within postconditions. Any equality that is active
and whose left hand side is an attribute (without a @pre modifier) or an output variable is interpreted as an assignment.
That is, an active equality attr1=E is interpreted as an assignment to attr1, so the final value of attr1 will be equal to E. To
avoid ambiguities, the expression E must refer only to input values and the previous state (using @pre). So if we want the
above postcondition to mean that attr2 is assigned the original value of attr1, we must write it as self.attr2 =
self.attr1@pre.


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