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The current QVTi AS wraps any Statement that may have a hazardous property acess in an ObservableStatement that enumerates each of the hazradous properties. This was perhaps a sensible markup when OCL expressions could be unthinkingly copied directly from qvtm to qvti; no intervening qvts. The markup identifies the NavigationCallExp's for which the QVTi executor must await ready data. The markup is a pessimistic fudge that avoids the need (text+CS+AS) for observable property calls. With the addition of the QVTiProductionConsumption design rule check, the pessimism can report spurious missing notifies. (There are no observable operation calls since the operation caller is required to anticipate all hazrds within the operation as hazrds in the call preamble.) Solutions: - no QVTiProductionConsumption - richer observable markup - add derived source, target classes - ObservablePropertyCallExp - needs Bug 546497 - dedicated Statement Now that QVTi is fully synththesized from QVTs is should be possible to impose a 'let-variable' on each property call. var yyy : DerivedYYYType = ...; observe var xxx : DerivedXXXType = yyy.zzz; rather than observe YYY::zzz ..... ...zzz... The underlying executor pretty much needs the variable anyway as part of the is-it-ready checking. Bye bye ObservableStatement. Hello DeclareStatement.isObserve.
(In reply to Ed Willink from comment #0) > The current QVTi AS wraps any Statement that may have a hazardous property > acess in an ObservableStatement that enumerates each of the hazradous > properties. Correction. ObservableStatement is inherited by any Statement that might need observations. > Bye bye ObservableStatement. Hello DeclareStatement.isObserve. Bye Bye ObservableStatement::observedProperties. Hello ObservableStatement::isObserve. Semantics. If isObserve, all transitively contained PropertyCallExp's are observed using the prevailing OCL types as source/target. Corrolary a 'let-variable' is needed to have an unobserved sub-expression. Corrolary a 'let-variable' is needed to enforce stronger derived source/target classes.
