| 1 | #ifndef ITERATOR_H
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| 2 | #define ITERATOR_H
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| 3 | 
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| 4 | #include "iostream.h"
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| 5 | 
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| 6 | // An iterator can be used to traverse a data structure.
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| 7 | context iterator( type iterator_type, type elt_type ) {
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| 8 |     // point to the next element
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| 9 | //    iterator_type ?++( iterator_type * );
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| 10 |     iterator_type ++?( iterator_type * );
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| 11 |     iterator_type --?( iterator_type * );
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| 12 | 
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| 13 |     // can be tested for equality with other iterators
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| 14 |     int ?==?( iterator_type, iterator_type );
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| 15 |     int ?!=?( iterator_type, iterator_type );
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| 16 | 
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| 17 |     // dereference to get the pointed-at element
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| 18 |     lvalue elt_type *?( iterator_type );
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| 19 | };
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| 20 | 
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| 21 | context iterator_for( type iterator_type, type collection_type, type elt_type | iterator( iterator_type, elt_type ) ) {
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| 22 | //    [ iterator_type begin, iterator_type end ] get_iterators( collection_type );
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| 23 |     iterator_type begin( collection_type );
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| 24 |     iterator_type end( collection_type );
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| 25 | };
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| 26 | 
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| 27 | forall( type iterator_type, type elt_type | iterator( iterator_type, elt_type ) )
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| 28 | void for_each( iterator_type begin, iterator_type end, void (*func)( elt_type ) );
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| 29 | 
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| 30 | // writes the range [begin, end) to the given stream
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| 31 | forall( type elt_type | writeable( elt_type ),
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| 32 |         type iterator_type | iterator( iterator_type, elt_type ),
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| 33 |         dtype os_type | ostream( os_type ) )
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| 34 | void write_all( iterator_type begin, iterator_type end, os_type *os );
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| 35 | 
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| 36 | forall( type elt_type | writeable( elt_type ),
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| 37 |         type iterator_type | iterator( iterator_type, elt_type ),
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| 38 |         dtype os_type | ostream( os_type ) )
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| 39 | void write_reverse( iterator_type begin, iterator_type end, os_type *os );
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| 40 | 
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| 41 | #endif // ITERATOR_H
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