CODEWITHSUNDEEP
haskell
A. Lindberg
A. Lindberg

Reputation: 316

Convert operator character to corresponding function

Is there a way to convert the characters '+', '-', '*', '/' to the corresponding functions? I mean a function like this (obviously I tried it and it didn't work):

toOperator :: Num a => String -> a -> a -> a
toOperator c = read c :: Num a => a -> a -> a

Upvotes: 2

Views: 1145

Answers (1)

karakfa
karakfa

Reputation: 67497

You can easily define a partial function for this purpose with pattern matching

Prelude> :set +m
Prelude> let f '+' = (+)
Prelude|     f '-' = (-)
Prelude|     f '*' = (*)
Prelude|     f '/' = (/)
Prelude|
Prelude> f '*' 3 4
12.0
Prelude> f '+' 1 2
3.0
Prelude>

and the deduced type

Prelude> :t f
f :: Fractional a => Char -> a -> a -> a

Upvotes: 3

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