On Sun, Nov 18, 2012 at 7:27 AM, Albert Y. C. Lai
<trebla@vex.net> wrote:
On 12-11-17 02:19 AM, damodar kulkarni wrote:
Let's see tthis:
Prelude> :t 3 "a"
3 "a" :: (Num ([Char] -> t)) => t
No complaint from GHC; but now see this:
Prelude> :t "a" 3
<interactive>:1:0:
Couldn't match expected type `t1 -> t'
against inferred type `[Char]'
In the expression: "a" 3
Why does it not fail for (:t 3 "a") but does fail for (:t "a" 3)?
To make "a" polymorphic, turn on OverloadedStrings:
:set -XOverloadedStrings
:type "a"
"a" :: Data.String.IsString a => a
:type "a" 3
"a" 3 :: (Num a, Data.String.IsString (a -> t)) => t
Success!
This is clearly depravity.