On Fri, Jul 01, 2011 at 09:05:05AM +1000, Ivan Lazar Miljenovic wrote: > On 1 July 2011 08:58, Joshua Ball <joshbb...@gmail.com> wrote: > > GHCi seems to be clever about some things: > > > > If I try to print the empty list in ghci, I encounter no problems: > > > > Prelude> [] > > [] > > Prelude> show [] > > "[]" > > Prelude> print [] > > [] > > > > Even though the type of the list is clearly unknown, it must be > > picking SOME type. (why does it print [] instead of "")? > > Type defaulting: if you don't specify a type, then ghci makes it > [Integer].
In this case I'm pretty sure it is [()] since there is only a Show constraint. If there were a Num constraint it would pick Integer. Prelude> sum [] 0 Prelude> :t it it :: Integer -Brent _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
