Changes between Version 2 and Version 3 of ClosedClasses


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Timestamp:
Dec 6, 2005 5:09:24 AM (10 years ago)
Author:
john@…
Comment:

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  • ClosedClasses

    v2 v3  
    1414this will mean that even if the class is exported no one may declare more instances for it
    1515
    16 == alternate ==
     16== alternate, better proposal ==
    1717
    1818specify it in the export list
     
    2222}}}
    2323
     24this has the advantage that you can create instances in several modules in a private implementation then export them closed in the public interface. it also fits in nicely with the idea of explicit namespaces in  the ModuleSystem and the readonly modifier in the ReadonlyConstructors proposal.
    2425
    2526== pro ==
     
    2728 * This sort of thing is often needed when doing phantom type and type class tricks.
    2829 * this is available in helium in order to increase the accuracy of error messages to good effect.
    29  * syntax is similar to 'class alias' and 'class overlapping' proposals
    30 
     30 
    3131== con ==
    3232