{"id":323561,"date":"2016-11-17T03:41:05","date_gmt":"2016-11-17T11:41:05","guid":{"rendered":"https:\/\/www.microsoft.com\/en-us\/research\/?post_type=msr-research-item&p=323561"},"modified":"2018-10-16T20:28:13","modified_gmt":"2018-10-17T03:28:13","slug":"levity-polymorphism","status":"publish","type":"msr-research-item","link":"https:\/\/www.microsoft.com\/en-us\/research\/publication\/levity-polymorphism\/","title":{"rendered":"Levity polymorphism"},"content":{"rendered":"

Parametric polymorphism is one of the lynchpins of modern typed programming. A function that can work seamlessly over a variety of types simplifies code, helps to avoid errors introduced through duplication, and is easy to \u00a0maintain. However, polymorphism comes at a very real cost, one that each language with support for polymorphism has paid in different ways. This paper describes this cost, proposes a theoretically simple way to reason about the \u00a0cost—that kinds<\/em>, not types, are calling conventions—and details one approach to dealing with polymorphism that works in the context of a language, Haskell, that prizes both efficiency and a principled type system.<\/p>\n

This approach, levity polymorphism<\/em>, allows the user to abstract over calling conventions; we detail and verify restrictions that are necessary in order to compile levity-polymorphic functions. Levity polymorphism has opened up surprising new opportunities for library design in Haskell.<\/p>\n","protected":false},"excerpt":{"rendered":"

Parametric polymorphism is one of the lynchpins of modern typed programming. A function that can work seamlessly over a variety of types simplifies code, helps to avoid errors introduced through duplication, and is easy to \u00a0maintain. However, polymorphism comes at a very real cost, one that each language with support for polymorphism has paid in […]<\/p>\n","protected":false},"featured_media":0,"template":"","meta":{"msr-url-field":"","msr-podcast-episode":"","msrModifiedDate":"","msrModifiedDateEnabled":false,"ep_exclude_from_search":false,"_classifai_error":"","msr-author-ordering":null,"msr_publishername":"ACM","msr_publisher_other":"","msr_booktitle":"","msr_chapter":"","msr_edition":"","msr_editors":"","msr_how_published":"","msr_isbn":"","msr_issue":"","msr_journal":"","msr_number":"","msr_organization":"","msr_pages_string":"525-539","msr_page_range_start":"525","msr_page_range_end":"539","msr_series":"","msr_volume":"","msr_copyright":"","msr_conference_name":"ACM Conference on Programming Language Design and Implementation 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