| [section:style_guide Terminology and style guidelines] |
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| The use of a consistent terminology is as important for __ranges__ and range-based algorithms as it is for iterators and iterator-based algorithms. If a conventional set of names are adopted, we can avoid misunderstandings and write generic function prototypes that are [*/self-documenting/]. |
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| Since ranges are characterized by a specific underlying iterator type, we get a type of range for each type of iterator. Hence we can speak of the following types of ranges: |
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| * [*/Value access/] category: |
| * Readable Range |
| * Writeable Range |
| * Swappable Range |
| * Lvalue Range |
| * [*/Traversal/] category: |
| * __single_pass_range__ |
| * __forward_range__ |
| * __bidirectional_range__ |
| * __random_access_range__ |
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| Notice how we have used the categories from the __new_style_iterators__. |
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| Notice that an iterator (and therefore an range) has one [*/traversal/] property and one or more properties from the [*/value access/] category. So in reality we will mostly talk about mixtures such as |
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| * Random Access Readable Writeable Range |
| * Forward Lvalue Range |
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| By convention, we should always specify the [*/traversal/] property first as done above. This seems reasonable since there will only be one [*/traversal/] property, but perhaps many [*/value access/] properties. |
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| It might, however, be reasonable to specify only one category if the other category does not matter. For example, the __iterator_range__ can be constructed from a Forward Range. This means that we do not care about what [*/value access/] properties the Range has. Similarly, a Readable Range will be one that has the lowest possible [*/traversal/] property (Single Pass). |
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| As another example, consider how we specify the interface of `std::sort()`. Algorithms are usually more cumbersome to specify the interface of since both [*/traversal/] and [*/value access/] properties must be exactly defined. The iterator-based version looks like this: |
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| `` |
| template< class RandomAccessTraversalReadableWritableIterator > |
| void sort( RandomAccessTraversalReadableWritableIterator first, |
| RandomAccessTraversalReadableWritableIterator last ); |
| `` |
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| For ranges the interface becomes |
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| `` |
| template< class RandomAccessReadableWritableRange > |
| void sort( RandomAccessReadableWritableRange& r ); |
| `` |
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| [endsect] |
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