[Seaside-dev] [Portability] WADynamicVariable >> defaultAction

[James Foster]

Philippe Marschall wrote:
> Hi
>
> Looking at the Gemstone port I found their implementation of
> WADynamicVariable >> defaultAction is:
>
> defaultAction
>     ^self class defaultValue
>
> which leaves it to the implementation how the problem should be solved
> whereas in normal Seaside it is:
>
> defaultAction
>     self resume: self class defaultValue
>
> In Squeak both work because in the later case is delegated to UndefinedObject
>
> handleSignal: exception
>     ^ exception resumeUnchecked: exception defaultAction
>
> From a portability point of view, which one is to be preferred?
>
> Cheers
> Philippe
>   
Hi Philippe,

"It is erroneous to directly or indirectly send this message [#resume:] 
from within a #defaultAction method to the receiver of the 
#defaultAction method." -- ANSI section 5.5.4.6

In GemStone, sending #resume: from within a #defaultAction method 
results in an walkback. Thus, the non-#resume: implementation is more 
portable and matches the ANSI Specification.

James