sorry to bother you. I'm new to haskell and trying to define a new type Person.
I'm using the GHCI compiler.
I'm running the file new.hs which includes:
Name = String
Age = Int
Weight = Int
Person = (Name, Age, Weight)
but I get not in scope errors. Can anyone help?
Jeremy D helped me with this and I solved that but how can I add a function such as:
isAdult :: Person -> Bool
George = ("George", 20, 80)
isAdult George = if Age >=18
try with:
type Name = String
type Age = Int
type Weigth = Int
type Person = (Name, Age, Weigth)
For a simple introduction, look here
To answer your second question, here is what I did:
newtype Name = Name String deriving (Show)
newtype Age = Age Int deriving (Show)
newtype Weigth = Weight Int deriving (Show)
newtype Person = Person (Name, Age, Weigth) deriving (Show)
isAdult :: Person -> Bool
isAdult (Person(_, Age a, _)) = a > 18
When executing it:
*Main> let p = Person(Name "Jeremy", Age 18, Weight 199)
*Main> p
Person (Name "Jeremy", Age 18, Weight 199)
*Main> isAdult p
False
*Main> let p = Person(Name "Jeremy", Age 20, Weight 199)
*Main> isAdult p
True
*Main>
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