Haskell Keywords

Define a “recip” function which takes the reciprocal of a fractional type value.

recip :: Fractional a => a → a
recip n = 1/n

How would you write the guarded equation version of the function abs, which finds the absolute value of an Int, Integer, Float or Double?

abs n | n >= 0 = n
| otherwise = -n

What does the ‘otherwise’ keyword imply?

It is defined in the prelude as otherwise = True.

What is the “:” symbol?

Called “cons”, it constructs a list by prepending a new element to teh start of an existing list.

What does the “\” symbol indicate?

A lambda expression!