Strings

Strings are essentially lists of (Unicode) characters and therefore many functions that operate on lists can also be used with strings:

(+) :: Additive a => a -> a -> a (Prelude)

Adds two objects (numbers, vectors, strings, etc.) together.

sum :: Additive a => [a] -> a (Prelude)

Sum of the elements:

sum [e1,e2,...,eN] = e1 + e2 + ... + eN

Implemented usually more efficiently than with repetitive application of (+).

length :: Sequence a => a -> Integer (Prelude)

Length of the sequence

take :: Sequence a => Integer -> a -> a (Prelude)

take n s returns the first n elements of the sequence s.

drop :: Sequence a => Integer -> a -> a (Prelude)

drop n s removes the first n elements of the sequence s.

sub :: Sequence a => a -> Integer -> Integer -> a (Prelude)

sub s begin end returns a subsequence of s starting from index begin and ending just before index end.

Strings have currently their own function for accessing indivial characters (but in the future they may also support ! operator).

charAt :: String -> Integer -> Character (Prelude)

charAt string i returns the ith character of the string.

The following operations are often useful for