Thank you so much :)
On Tue, Nov 24, 2015 at 2:01 PM, Francesco Ariis
On Tue, Nov 24, 2015 at 01:20:03PM -0500, Jeon-Young Kang wrote:
Dear All.
I'd like to compare fields of each record.
here is my record.
data Person = Person {name:: String, age:: Int } deriving(Show) data Relations = Friend | Older | Younger
class Comparison a where compare:: a -> a -> Relations
instance Comparison Person where compare Person a b Person a b | b1 == b2 = Friend | b1 > b2 = Older | b1 < b2 = Younger
How can I fit it?
Sincerely,
Jeon-Young Kang
Hello Jeon-Young, I attach a version that compiles. Keep in mind that
compare (Person x y) (Person q w) -- this is legal
compare Person x y Person q w -- "space" takes precedence over everything, -- so this function has 6 arguments -- instead of the expected 2!
λ> Main.compare (Person "cdsac" 1) (Person "cdscasd" 20) Younger
-- Department of Geography State University of New York at Buffalo jykang22@gmail.com Jeon-Young Kang