> FrEd (Functional Reactive Editor library)
  
MACROS
-------
To get the basic macros: 
(require (lib "mixin-macros.ss" "frtime" "demos" "gui"))

> (events->callbacks field-name update-call)
Generates a mixin for allowing an event stream to drive
callbacks. When an event stream is given as the init
value for field-name, that event stream is stored,
and whenever an event occurs on that stream, 
update-call is invoked on the value of the event. The
one argument to the resulting mixin is the class being
extended

> (callbacks->args-evts stream-name callback)
Generates a mixin that sends an event on stream-name when
callback is called. The class has an init field called
[stream-name]-event-processor, whose value is a function.
The public method (get-[stream-name]) of the resulting class
gets the result of applying [stream-name]-event-processor 
to the stream of args-evts. The events on the stream are
lists of the arguments to the callback. The default value 
for [stream-name]-event-processor is given as the first
argument to the mixin, and the class being extended is
the second argument to the mixin.

FtA provides event-is-val, split-mouse-events/type, and
split-key-events/type for use as initialization arguments.
event-is-val can be used for [stream-name]-event-processor
when the event should just be the value of the first 
argument of the callback. split-*-events/type sets up an
appropriate split (see FrTime docs for split information,
MrEd docs for key-event codes and mouse-event types) over
the type of event occurence.

                                                    
events->callbacks and callbacks->args-evts are the backbone
of the transition between an object-oriented library and
an event-stream based library. Some common utility macros
are provided from:
(lib "aux-mixin-macros.ss" "frtime" "demo" "gui")
                                                    
> (behavior->callbacks field-name update-call)
Generates a mixin for allowing a behavior to control a widget.
The mixin has two arguments. The mixin's first argument is the
default value for field-name, and the seconds argument is the
class being mixed. Whenever a behavior is supplied as the value
for field-name, the value-now of that behavior is used as the
super-new argument for filed-name, and whenever there is a
change in that behavior, update-call is invoked with the
current value of the behavior.

> (mixin-merge-e new-stream-name stream-getter1 stream-getter2)
Generates a mixin that provides access to the merge-e
of two event streams. The first argument is the name
of the merged stream. The merged stream can be accessed
by the public method (get-[new-stream-name]). The
method stream-getter1 and stream-getter2 are assumed to
be inherited public methods that return event streams.


For examples of how to use these macros, look at the file
"instr.ss" in collects/frtime/demos/gui/demo.



MIXINS
------
Some common mixins have already been defined and applied.
To get these: 
(require "fred.ss" "frtime" "demos" "gui")

> (add-mouse-access super-class)
Derived from callbacks->args-evts.
 stream-name: mouse-events
 
> (add-focus-access super-class)
Derived from callbacks->args-evts
 stream-name: focus-events

> (add-keypress-split super-class)
Derived from callbacks->args-evts.
 stream-name: key-events
 
> (add-callback-access value-extractor default-value super-class)
value-extractor is a method of two arguments (a widget
and a control event) that gets a value for the widget.
default-value is the default value for the widget. Adds
(get-value-e) and (get-value-b) to super-class, where
get-value-e returns an event stream representing the
value of the widget, and get-value-b returns a behavior
representing the value of the widget.

> (add-callback-access/loop value-extractor default-value super-class)
does the work of add-callback-access, but also adds
an initialization argument value-set, which is an
event stream that sets the value of the widget at
each event.

> (add-focus-on-event super-class)
Derived from events->callbacks.
 field-name: focus-when
 

UTILITY
-------

> (standard-lift widget value-method value-default)
standard-lift applys a common set of mixins to the
widget. It applies add-mouse-access, add-focus-access,
and it applys the result of behavior->callback for
label and enable. It also applies add-callback-access
with value-method as the value-extractor, and
value-default as the default-value.
Widgets that have been standard-lift'ed:
ft-button%
ft-radio-box%
ft-choice%
ft-list-box%


> (standard-lift/loop widget value-method value-default)
standard-lift/loop is the same as standard-lift,
except thatit applies add-callback-access/loop
instead of add-callback-access.
Widgets that have been standard-lift/loop'ed:
ft-check-box%
ft-slider%
ft-text-field%


simple.ss
---------

Many useful utilities have been put in
(require "simple.ss" "frtime" "demos" "gui")
feel free to look around and use the ones you think are
useful.
  
