A Default Identity Value for Programmingmichaelfeathers.silvrback.com 2 pointsfarginay12 years ago2 commentsSaveHideCopy link On HNComments−npryce12yJ has a similar feature: when applied to an empty array, /+ returns 0 and /* returns 1.J doesn't have user-defined types. In a language with user-defined types, you would probably have to declare which operations are monoids.−dvberkel12yI would concur with npryce. I your structure would adhere to the monoid interface and the default value could be cast automatically to the corresponding identity this will work. It wouldn't even break mathematics
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J has a similar feature: when applied to an empty array, /+ returns 0 and /* returns 1.
J doesn't have user-defined types. In a language with user-defined types, you would probably have to declare which operations are monoids.
I would concur with npryce. I your structure would adhere to the monoid interface and the default value could be cast automatically to the corresponding identity this will work. It wouldn't even break mathematics