Re: [qvtd-dev] ClassToRDBMSSchedule.qvti review

[Ed Willink <ed@xxxxxxxxxxxxx>]

HI

You are using a very odd mail tool; your comments are hard to distinguish.

Hopefully mine are more distinct.

    Regards

        Ed


On 22/04/2013 12:38, Horacio Hoyos Rodriguez wrote:
> [Horacio Hoyos Rodriguez]
> This will mean analysing the mapping guard predicates to change their
> direction and to make the binding change them to assignments. On a mapping
>
> call perspective it means that not all variables need to be bind in the
> mapping call (optional parameters?). My initial proposal is not optimal
> but for the moment I think it is more straight forward to compute. Your
> proposal is more optimal but requires more intelligence on the QVTc to
> QVTi translation. I think we should start with a simple and not optimal
> QVTc to QVTi translation which we can easily program into Epsilon (and
> then QVT) and once that is working see how we can optimize it. The syntax
> error can be fixed by allowing mapping call variables to be used in the
> oclexpressions if they have been defined previously.
But the QVTc to QVTi does not yet exist, we are still designing 
it/manually prototyping its output..

The QVTi executor does and we're trying to get that right.

Introducing a new visibility to support a very inefficient 
mis-inplementation cannot be right.
> Clearly the underlying mapping call implementation should have a recipient
>
> type filter so that it is sufficient to write
>
>       map associationToForeignKeyLM {
>           p := p;
>           a <= p.elements;
>           p2s := p2s;
>       }
>
> [Horacio Hoyos Rodriguez]
> I was thinking about this too. The GuardPatternVisitor will need
> modification to test if the binded value of the variable is of the precise
>
> type. Should the match be exact or will super types be accepted as valid
> matches?
In OO tools, types should almost always be compared with support for 
inheritance.

Type.conformsTo(Type) is probably what you need.
> --------------------------------------------------------------------------
>
> ------
>
> The queries need implementation.
> [Horacio Hoyos Rodriguez]
> How do I pass the queries to the environment? Do I need to visit them so
> OCL knows to what type to associate the query?
> On a side note on this, the getAllForwards query in the QVT specification
> refers to the forward attribute of the Class class. I don't have this
> reference in my SimpleUML metamodel, so will you agree this is the
> opposite of the source reference in the Association class?
>
> You might postpone this for now by inlining them with the aid of the
> closure iteration.
In many respects the correct implementation of a Query is the same as a 
Mapping (without loops).
You create a new nested environment and bind all the query parameters to 
the invoking arguments.

    Regards

        Ed