Constrained genericity: Difference between revisions
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<lang haskell>instance (Food a) => Eatable a where |
<lang haskell>instance (Food a) => Eatable a where |
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eat x = munch x</lang> |
eat x = munch x</lang> |
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=={{header|J}}== |
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J is not a statically typed language, but I do not see why we should not implement this in J: |
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<lang j>coclass'Connoisseur' |
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isEdible=:3 :0 |
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0<nc<'eat__y' |
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) |
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coclass'FoodBox' |
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create=:3 :0 |
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assert isEdible_Connoisseur_ type=:y |
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collection=: 0#y |
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) |
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add=:3 :0"0 |
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'inedible' assert type e. copath y |
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collection=: collection, y |
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)</lang> |
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An edible type would be a class that has a verb with the name 'eat'. For example: |
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<lang j>coclass'Apple' |
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eat=:3 :0 |
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smoutput'delicious' |
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)</lang> |
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And here is a quicky demo of the above: |
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<lang j> |
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lunch=:(<'Apple') conew 'FoodBox' |
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a1=: conew 'Apple' |
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a2=: conew 'Apple' |
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add__lunch a1 |
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add__lunch a2 |
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george=: conew 'Connoisseur' |
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add__lunch george |
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|inedible: assert</lang> |
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=={{header|Java}}== |
=={{header|Java}}== |
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<lang java5>test.<EatableClass>bar();</lang> |
<lang java5>test.<EatableClass>bar();</lang> |
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The <code>foo</code> method from before can figure out <code>T</code> from its parameter, but this <code>bar</code> method needs to be told what T is. |
The <code>foo</code> method from before can figure out <code>T</code> from its parameter, but this <code>bar</code> method needs to be told what T is. |
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=={{header|OCaml}}== |
=={{header|OCaml}}== |
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