Changes between Version 2 and Version 3 of ClosedClasses


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Timestamp:
Dec 6, 2005 5:09:24 AM (9 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