24 May
2013
24 May
'13
1:41 p.m.
On Sat 25 May 2013 00:37:59 SGT, TP wrote:
Is this the right way to go? Is there any other solution?
I believe whether it's right or just depends on what you want to express.
Do you confirm that tilde in s~s1 means "s has the same type as s1"?
It means: Both your s and s1 are "Eq"s but not necessarily the same one. Your first example allows that, so you could have one with an Int and one with a String inside (both are Eqs). a = Box 1 b = Box "hello" Now if that first code compiled, your code (Box s1) == (Box s2) = s1 == s2 would effectively perform ... = 1 == "hello" which is not possible.