Re: [Reuseware-devel] type casting in composition programs

[Jakob H. <jak...@tu...>]

On Fri, 07 Sep 2007 23:38:44 +0200, Sven Karol  =

<s78...@in...> wrote:

> Hello again!
>
> We could do something which compares attribute types of two fragment  =

> types to determine if a cast is possible. And if the attributes are  =

> compatible we could create a new fragment of the type to which  we wan=
t  =

> to cast having the same values as the old fragment. But this is in fac=
t  =

> not casting, it is more like cloning or converting, since casting (in =
 =

> the classical java sence) allways threats one object/fragment which  =

> might be referenced by different variables/fragmentlists.
>
>  >However, I'm guessing that this situation will appear in other  =

> scenarios
>  >in the future as well. So, the question is what we should do.
>
> It happend allready to me, but I thought the string concatenation was =
 =

> the way to go because it was implemented and used in some examples.

Right, it works, which is nice for the moment. But in the long run it's =
 =

not really desirable, since it is type unsafe.

Cheers,
Jakob

>
> Sven.
>
>
>
>
> Jakob Henriksson schrieb:
>> Hi,
>>
>> They might not be type compatible, I'm not really sure. What I'm sure=
   =

>> about is that I want a solution which doesn't step outside the type  =

>> system  (which is currently the case). Maybe a solution for Modular  =

>> Xcerpt is  possible to find, by using different types from Xcerpt, no=
t  =

>> to use  componentmodel.Location etc. I don't know exactly in this ver=
y  =

>> moment how  it can be solved, but probably somehow.
>>
>> However, I'm guessing that this situation will appear in other  =

>> scenarios  in the future as well. So, the question is what we should =
do.
>>
>> Going back to the example. What I want to bind is a QuotedString (i.e=
.  =

>> the  slot). What I have is a Location. The value of a location is a  =

>> string. If  you define a QuotedString to be:
>>
>> QuotedString	=3D	"\"" value:S "\"";
>>
>> (or something to that effect), then the values of Location and   =

>> QuotedString are really the same. Here, the '"'s are really just  =

>> concrete  syntax, aren't they? Somehow it seems that the values from =
 =

>> the different  types in this case can be cast to each other (it might=
  =

>> not always be  possible, but in this case it is, which is why we coul=
d  =

>> successfully  employ a cast).
>>
>> Anyway, discussion will hopefully continue.
>>
>> Please CC "Reuseware Developer"   =

>> <reu...@li...> on all mailing discussion=
s  =

>> so  that everybody can follow the discussions and so that it will end=
  =

>> up in  the mailing list archives later on. It will be interesting to =
 =

>> have. It  also shows some activity to the outside world ;)
>>
>> Cheers,
>> Jakob
>>
>>
>> On Fri, 07 Sep 2007 17:37:20 +0200, Sven Karol   =

>> <s78...@in...> wrote:
>>
>>
>>> Hi!
>>>
>>> I really dont know if a simple cast would be the right solution here=
,   =

>>> since "componentmodel.Location" and  "xcerpt.QuotedString" are not  =

>>> type  compatible (aren't they?). Because of that, you really need   =

>>> that  information  about concrete syntax as it is used by the string=
   =

>>> concatenation,  so something like
>>>
>>>     > bind moduleID on qtWrapper with   =

>>> (xcerpt.QuotedString)'"'moduleID'"'.mxcerpt;
>>>
>>> is possible to be implemented. If we really want to have
>>>
>>>     > bind moduleID on qtWrapper with (xcerpt.QuotedString)moduleID;=

>>>
>>> reuseware would have to check all concrete Syntaxes registered as   =

>>> parser/printer for "xcerpt.QuotedString" for prefixes and suffixes  =

>>> ('"'  and '"' in the case of mxcerpt) and do the string concatenatio=
n   =

>>> internally. Of course this would work in some very special cases onl=
y   =

>>> and has no clear semantics to the user. Additionally I currently do =
 =

>>> not  know if the concrete Syntax is accessible as far as one would  =

>>> need for  implementation of that feature, but I guess not.
>>>
>>>
>>> greetz,
>>>     Sven.
>>>
>>
>>
>>
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