The signal module provides a basic implementation of the listener pattern
using the "Signals and Slots" model from Qt.
License:
BSD style: see license.txt
Authors:
Sean Kelly
- struct
Signal
(Args...);
- A signal is an event which contains a collection of listeners (called
slots). When a signal is called, that call will be propagated to each
attached slot in a synchronous manner. It is legal for a slot to call a
signal's attach and detach methods when it is signaled. When this occurs,
attach events will be queued and processed after the signal has propagated
to all slots, but detach events are processed immediately. This ensures
that it is safe for slots to be deleted at any time, even within a slot
routine.
Example:
class Button
{
Signal!(Button) press;
}
void wasPressed( Button b )
{
printf( "Button was pressed.\n" );
}
Button b = new Button;
b.press.attach( &wasPressed );
b.press( b );
Please note that this implementation does not use weak pointers to store
references to slots. This design was chosen because weak pointers are
inherently unsafe when combined with non-deterministic destruction, with
many of the same limitations as destructors in the same situation. It is
still possible to obtain weak-pointer behavior, but this must be done
through a proxy object instead.
- alias
SlotDg
;
- alias
SlotFn
;
- alias
call
;
- Alias to simplify chained calling.
- void
opCall
(Args args);
- The signal procedure. When called, each of the attached slots will be
called synchronously.
args = The signal arguments.
- void
attach
(SlotDg dg);
- Attaches a delegate to this signal. A delegate may be either attached
or detached, so successive calls to
attach
for the same delegate will
have no effect.
dg = The delegate to
attach
.
- void
attach
(SlotFn fn);
- Attaches a function to this signal. A function may be either attached
or detached, so successive calls to
attach
for the same function will
have no effect.
fn = The function to
attach
.
- void
detach
(SlotDg dg);
- Detaches a delegate from this signal.
dg = The delegate to
detach
.
- void
detach
(SlotFn fn);
- Detaches a function from this signal.
fn = The function to
detach
.
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