package fmlib

A list of values of type 'a.

return a makes a singleton list with the element a.

l >>= f applies the function f to all elements of the list l and concatenates all lists.

let* a = m in f a is equivalent to m >>= f.

f >=> g composes the two monadic functions f and g.

flst <*> lst is equivalent to flst >>= fun f -> map f lst i.e. it maps all functions contained in flst over the list lst and then concatenates the results.

join is the same as concat.

find p l finds an element e in the list l which satisfies p e.

append a b concatenate the lists a and b.

Synonym a @ b.

concat ll concatenates all lists contained in the list of lists ll.

Transform a list of pairs into a pair of lists.

rev a reverses the list a.

rev_append a b prepends the lists rev a in front of the list b.

length l The length of the list l.

filter p l Returns a list with all the elements of l which satisfy the predicate p.

fold_left f s l

Compute f (f ... (f a b1) ... bn-1) bn where l = [b1; ...; bn-1; bn]

like fold_left, just iterate from right to left.

map f l returns a list where all elements of l are mapped by the function f.

mapi f l map all elements of the list l with the mapping function f which receives the index of the element (starting at zero) and the element.

rev_map f l The same as map (rev l). rev_map is tail recursive.

for_all p l checks, if all elements in the list l satisfy the predicate p.

exists p l checks, if some element in the list l satisfies the predicate p.

split_head_tail l split the list in its head and tail part.

Precondition: The list is not empty.

map_and_filter f list maps the list with f and removes the element for which f e = None.

split_at p lst scans the list until it finds the first element satisfying p and returns the prefix and the remainder starting at the encountered element. If the second list is empty, then there is no element in the list satisfying p.

transpose list_of_rows returns the list of columns.

Preconditions:

• The list of rows must not be empty.

• All rows in the list of rows must not be empty and have the same length.

Example:

transpose [ [1; 2; 3]; [4; 5; 6] ]
=
[ [1; 4]; [2; 5]; [3; 6] ]

Monadic list functions