Creating pools (for example pools of connections to a database).
Instead of creating a new connection each time you need one, keep a pool of opened connections and reuse opened connections that are free.
Type of pools
create n ?check ?validate f
creates a new pool with at most
n
members. f
is the function to use to create a new pool
member.
An element of the pool is validated by the optional validate
function before its use. Invalid elements are re-created.
The optional function check
is called after a use
of an
element failed. It must call its argument exactly once with
true
if the pool member is still valid and false
otherwise.