The Essence of the Iterator Pattern
The Iterator pattern gives a clean interface for element-by-element access to a collection. Imperative iterations using the pattern have two simultaneous aspects: <em>mapping</em> and <em>accumulating</em>. Various existing functional iterations model one or other of these, b...
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| Format: | Journal article |
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2009
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| _version_ | 1826283163206287360 |
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| author | Gibbons, J Oliveira, B |
| author_facet | Gibbons, J Oliveira, B |
| author_sort | Gibbons, J |
| collection | OXFORD |
| description | The Iterator pattern gives a clean interface for element-by-element access to a collection. Imperative iterations using the pattern have two simultaneous aspects: <em>mapping</em> and <em>accumulating</em>. Various existing functional iterations model one or other of these, but not both simultaneously. We argue that McBride and Paterson's <em>applicative functors</em>, and in particular the corresponding <em>traverse</em> operator, do exactly this, and therefore capture the essence of the Iterator pattern. We present some axioms for traversal, and illustrate with a simple example, the <em>wordcount</em> problem. |
| first_indexed | 2024-03-07T00:54:46Z |
| format | Journal article |
| id | oxford-uuid:87a8d92c-017c-4b3f-89a1-ac3056ad51d7 |
| institution | University of Oxford |
| last_indexed | 2024-03-07T00:54:46Z |
| publishDate | 2009 |
| record_format | dspace |
| spelling | oxford-uuid:87a8d92c-017c-4b3f-89a1-ac3056ad51d72022-03-26T22:12:08ZThe Essence of the Iterator PatternJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:87a8d92c-017c-4b3f-89a1-ac3056ad51d7Department of Computer Science2009Gibbons, JOliveira, BThe Iterator pattern gives a clean interface for element-by-element access to a collection. Imperative iterations using the pattern have two simultaneous aspects: <em>mapping</em> and <em>accumulating</em>. Various existing functional iterations model one or other of these, but not both simultaneously. We argue that McBride and Paterson's <em>applicative functors</em>, and in particular the corresponding <em>traverse</em> operator, do exactly this, and therefore capture the essence of the Iterator pattern. We present some axioms for traversal, and illustrate with a simple example, the <em>wordcount</em> problem. |
| spellingShingle | Gibbons, J Oliveira, B The Essence of the Iterator Pattern |
| title | The Essence of the Iterator Pattern |
| title_full | The Essence of the Iterator Pattern |
| title_fullStr | The Essence of the Iterator Pattern |
| title_full_unstemmed | The Essence of the Iterator Pattern |
| title_short | The Essence of the Iterator Pattern |
| title_sort | essence of the iterator pattern |
| work_keys_str_mv | AT gibbonsj theessenceoftheiteratorpattern AT oliveirab theessenceoftheiteratorpattern AT gibbonsj essenceoftheiteratorpattern AT oliveirab essenceoftheiteratorpattern |