oracular (3) Stdlib.Fun.3o.gz

NAME

       Stdlib.Fun - no description

Module

       Module   Stdlib.Fun

Documentation

       Module Fun
        : (module Stdlib__Fun)

   Combinators
       val id : 'a -> 'a

       id is the identity function. For any argument x , id x is x .

       val const : 'a -> 'b -> 'a

       const c is a function that always returns the value c . For any argument x , (const c) x is c .

       val compose : ('b -> 'c) -> ('a -> 'b) -> 'a -> 'c

       compose f g is a function composition of applying g then f .  For any arguments f , g , and x , compose f
       g x is f (g x) .

       Since 5.2

       val flip : ('a -> 'b -> 'c) -> 'b -> 'a -> 'c

       flip f reverses the argument order of the binary function f . For any arguments x and y , (flip f) x y is
       f y x .

       val negate : ('a -> bool) -> 'a -> bool

       negate p is the negation of the predicate function p . For any argument x , (negate p) x is not (p x) .

   Exception handling
       val protect : finally:(unit -> unit) -> (unit -> 'a) -> 'a

       protect  ~finally  work  invokes  work () and then finally () before work () returns with its value or an
       exception. In the latter case the exception is re-raised after finally ()  .  If  finally  ()  raises  an
       exception, then the exception Fun.Finally_raised is raised instead.

       protect  can be used to enforce local invariants whether work () returns normally or raises an exception.
       However, it does not protect against unexpected exceptions raised inside finally () such as Out_of_memory
       , Stack_overflow , or asynchronous exceptions raised by signal handlers (e.g.  Sys.Break ).

       Note:  It  is  a  programming error if other kinds of exceptions are raised by finally , as any exception
       raised in work () will be lost in the event of a Fun.Finally_raised exception. Therefore, one should make
       sure to handle those inside the finally.

       exception Finally_raised of exn

       Finally_raised  exn  is  raised  by  protect  ~finally  work  when finally raises an exception exn . This
       exception denotes either an unexpected exception or a programming error. As a general  rule,  one  should
       not catch a Finally_raised exception except as part of a catch-all handler.