Created
November 9, 2012 14:00
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newtype vs data in haskll
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| Prelude> data D = D Int | |
| Prelude> let f (D i) = "ok" | |
| Prelude> f undefined | |
| "*** Exception: Prelude.undefined | |
| Prelude> newtype D = D Int | |
| Prelude> let f (D i) = "ok" | |
| Prelude> f undefined | |
| "ok" |
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Just ran in to the same issue and got the same result as you ... took forever to figure out what the issue was. Thanks for posting this.
I found this link from this StackOverflow comment.