exists : ('a -> bool) -> 'a list -> bool

SYNOPSIS

Check if a predicate holds somewhere in a list

DESCRIBE

An invocation exists P l returns true if P holds of some element of l. Since there are no elements of [], exists P [] always returns false.

FAILURE

When searching for an element of l that P holds of, it may happen that an application of P to an element of l raises an exception. In that case, exists P l raises an exception.

EXAMPLE
    - exists (fn i => i mod 2 = 0) [1,3,4];
    > val it = true : bool

    - exists (fn _ => raise Fail "") [];
    > val it = false : bool

    - exists (fn _ => raise Fail "") [1];
    ! Uncaught exception: 
    ! Fail  ""

SEEALSO  Lib,   all,   first,   tryfind

HOL  Kananaskis 0