@node Atomic Operations and Datastructures
@section Atomic Operations and Datastructures

@code{(hnh util atomic)}

@defmac with-mutex mutex body ...
Equivalent to Guile's @code{with-mutex} from
@code{(ice-9 threads)}.
Re-implemented to be able to drop an ice-9 dependency@c
@footnote{As if Scheme will ever be portable enough for that to matter}.
@end defmac

A few ``atomic'' data structures are also available. These allow
synchronized insertion and removal from the set.

@node Atomic Queue
@subsection Atomic Queue

@code{(hnh util atomic-queue)}

@defun atomic-queue
Create a new atomic queue. Each queue will internally syncronize all
modifications of state. Sepparate queue's don't affect each other.
@end defun

@defun atomic-queue? x
Check if @var{x} is an atomic queue?
@end defun

@defun enqueue! value queue
Add @var{value} to the back of @var{queue}.
@end defun

@defun queue-peek queue
Returns the first element of @var{queue}, or raises an exception if
the queue is empty.
@end defun

@defun dequeue! queue
remove and retrun the first element of @var{queue}, or @code{#f} if the queue is
empty.
@end defun

@defun queue->list queue
Extract contents of @var{queue}. With the front of the list in the car
slot, and subsequent elements following.
@end defun

@node Atomic Stack
@subsection Atomic Stack

@code{(hnh util atomic-stack)}

@defun atomic-stack
Creates a new atomic stack. See @code{atomic-queue} further details.
@end defun

@defun atomic-stack? x
Check if @var{x} is an atomic stack.
@end defun

@defun push! value stack
@end defun

@defun stack-peek stack
@end defun

@defun pop! value stack
@end defun

@defun stack->list stack
Extract the contents of @var{stack}. The topmost element will be first
in the returned list.
@end defun