dagit: > data and newtype vary in one more subtle way, and that's how/when they > evaluate to bottom. Most of the time they behave identically, but in the > right cases they act sightly differently. newtype is usually regarded as > more efficient than data. This is because the compiler can choose to > optimize away the newtype so that it only exists at type check time. I > think this is also possible with data in some, but not all, uses.
The compiler *must* optimise away the use. They're sort of 'virtual' data, guaranteed to have no runtime cost. -- Don _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
