wuxianliang/furp.ls

## furp.ls
import prelude

Signal = -> new (class SignalClass
  (register) ->
    @handlers = []
    register @send

  send: (value) ~>
    @_value = value
    for handler in @handlers => handler value
    @_memo = value

  new: (adder) ~>
    Signal (send) ~>
      @handlers.push adder send

  lift: (fn) ~>
    @new (send) -> (value) ->
      send fn value

  keep-if: (test) ~>
    @new (send) -> (value) ~>
      if test value then send value

  when-true: ~> @keep-if -> it

  foldp: (def, fn) ~>
    signal = @new (send) -> (value) ->
      send (fn value, signal._memo ? def)

  drop-repeats: (def) ~>
    signal = @keep-if (value) ~>
      signal._memo != value

  count: ~>
    @foldp 0, (value, memo) ->
      memo + 1

  delay: (ms) ~>
    @new (send) -> (value) ->
      _.delay (-> send value), ms

  throttle: (ms) ~>
    @new (send) ->
      _.throttle ((value) -> send value), ms

  latch: (ms) ~>
    signal = @new (send) ->
      send-false = _.debounce (-> send false), ms
      (value) -> send true; send-false()
    signal.drop-repeats()

  sample-on: (signal) ~>
    @new (send) ~>
      signal.lift ~> send @_value
      ->
)(...arguments) # use Signal constructor without 'new'


DomInput = (event, el = document) ->
  Signal (send) ~> $ el .on event, send


class Keyboard
  @isDown = (keyCode) ->
    updown = Signal (send) ->
      reg = (event) -> DomInput event .keep-if (event) ->
        event.keyCode == keyCode
      reg \keydown .lift -> send true
      reg \keyup   .lift -> send false
    updown.drop-repeats()

  @arrows = ->


class Mouse
  @position =
    Signal (send) ->
      for event in <[ mousemove mousedown mouseup ]>
        DomInput event
          .lift -> send x: it.clientX, y: it.clientY
  @isDown =
    Signal (send) ->
      DomInput \mousedown .lift -> send true
      DomInput \mouseup   .lift -> send false
  @isClicked =
    Signal (send) ->
      DomInput \click .lift -> send true; send false
  @clicks =
    Mouse.isClicked.when-true()


# examples

__ = -> console.log ...arguments;  it

Mouse.position
  .sample-on Mouse.clicks
  .lift -> __ 'mouse position on click', it

Mouse.position
  .latch 1000
  .lift ->
    if it is true => __ 'mouse is active'
    else __ 'mouse is inactive: not moved in 1 sec'

Keyboard.isDown 32
  .keep-true()
  .delay 500
  .count()
  .lift -> __ 'space presses (delayed): ', it

## index.html
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8"/>
</head>
<body>
<script src="components/prelude-ls/prelude-browser.js"></script>
<script src="components/underscore/underscore.js"></script>
<script src="components/jquery/jquery.js"></script>
<script src="furp.js"></script>
</body>
</html>
	import prelude

	Signal = -> new (class SignalClass
	(register) ->
	@handlers = []
	register @send

	send: (value) ~>
	@_value = value
	for handler in @handlers => handler value
	@_memo = value

	new: (adder) ~>
	Signal (send) ~>
	@handlers.push adder send

	lift: (fn) ~>
	@new (send) -> (value) ->
	send fn value

	keep-if: (test) ~>
	@new (send) -> (value) ~>
	if test value then send value

	when-true: ~> @keep-if -> it

	foldp: (def, fn) ~>
	signal = @new (send) -> (value) ->
	send (fn value, signal._memo ? def)

	drop-repeats: (def) ~>
	signal = @keep-if (value) ~>
	signal._memo != value

	count: ~>
	@foldp 0, (value, memo) ->
	memo + 1

	delay: (ms) ~>
	@new (send) -> (value) ->
	_.delay (-> send value), ms

	throttle: (ms) ~>
	@new (send) ->
	_.throttle ((value) -> send value), ms

	latch: (ms) ~>
	signal = @new (send) ->
	send-false = _.debounce (-> send false), ms
	(value) -> send true; send-false()
	signal.drop-repeats()

	sample-on: (signal) ~>
	@new (send) ~>
	signal.lift ~> send @_value
	->
	)(...arguments) # use Signal constructor without 'new'


	DomInput = (event, el = document) ->
	Signal (send) ~> $ el .on event, send


	class Keyboard
	@isDown = (keyCode) ->
	updown = Signal (send) ->
	reg = (event) -> DomInput event .keep-if (event) ->
	event.keyCode == keyCode
	reg \keydown .lift -> send true
	reg \keyup .lift -> send false
	updown.drop-repeats()

	@arrows = ->


	class Mouse
	@position =
	Signal (send) ->
	for event in <[ mousemove mousedown mouseup ]>
	DomInput event
	.lift -> send x: it.clientX, y: it.clientY
	@isDown =
	Signal (send) ->
	DomInput \mousedown .lift -> send true
	DomInput \mouseup .lift -> send false
	@isClicked =
	Signal (send) ->
	DomInput \click .lift -> send true; send false
	@clicks =
	Mouse.isClicked.when-true()


	# examples

	__ = -> console.log ...arguments; it

	Mouse.position
	.sample-on Mouse.clicks
	.lift -> __ 'mouse position on click', it

	Mouse.position
	.latch 1000
	.lift ->
	if it is true => __ 'mouse is active'
	else __ 'mouse is inactive: not moved in 1 sec'

	Keyboard.isDown 32
	.keep-true()
	.delay 500
	.count()
	.lift -> __ 'space presses (delayed): ', it
	<!DOCTYPE html>
	<html>
	<head>
	<meta charset="utf-8"/>
	</head>
	<body>
	<script src="components/prelude-ls/prelude-browser.js"></script>
	<script src="components/underscore/underscore.js"></script>
	<script src="components/jquery/jquery.js"></script>
	<script src="furp.js"></script>
	</body>
	</html>