I think they mean "new type" to mean a data declaration, rather than a newtype. I had to read it a few times before it clicked for me. Just a confusion in terminology. Adam Bergmark <adam@bergmark.nl> writes:
What you posted is the format for data declarations, not newtypes. Newtypes are required to have exactly one constructor:
newtype [context =>] simpletype = newconstr [deriving]
Adam
On Fri, Aug 12, 2016 at 4:43 PM, James Brown <james.brown5374@gmail.com> wrote:
In the Haskell report 2010, a data declaration has the format of:
For a new type, there could be zero or more data constructors. What's the use case for a new type that has zero data constructor?
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-- Jack