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Import Aggregators

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2010-01-20 11:50 by benjk -
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The following two approaches to import aggregation were discussed and rejected:

!!!!Re-Export by Default
Any module imported by a module might automatically be re-exported.

*Advantages: No additional syntax required.
*Disadvantages: Re-export cannot be turned off.

!!!!Implicit Re-Export
A definition part which imports one or more modules but exports no items on its own might be deemed to have the purpose of re-exporting all the imported modules ...

[@DEFINITION MODULE Collections;

IMPORT Stack, Queue, BinarySearchTree, Trie, HashTable, DynamicArray;

END Collections.@]

*Advantages: No additional syntax required.
*Disadvantages: Re-export will no longer work if the aggregate module is extended with declarations.

!!!!Importing the Aggregator
Importing @@Collections@@ brings all re-exported modules into scope ...

[@MODULE UseCollections;

IMPORT Collections;

VAR
    stack : Stack;
...

stack := Stack.New(size, status);
...

END UseCollections.@]
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