Pythonic-Reactive

NOTE: THIS IS STILL BEING DEVELOPED AND IS THEREFORE NOT RECOMMENDED FOR ANY SERIOUS DEVELOPMENT AT THIS TIME. TEST COVERAGE IS INCOMPLETE AND FEATURES ARE CHANGING!

Pythonic-Reactive contains reactive programming components developed for both the qork engine and the PyWeek29 game Butterfly Destroyers.

It's main features are:

Signals, slots, and connections
Reactive variables (Variables w/ change listeners)
Lazy variables (Variables that observe reactive or other lazy variables)
Reactive timer system with interpolation and easing
Utility functions that make working with these more "pythonic"

Basic Features

Signal

sig = Signal()
sig += lambda: print('hello ', end='')
sig += lambda: print('world')
sig() # hello world

Slots

# Make a signal

sig = Signal()

# Connect some slots (Note this is different from the above Signal example)

hello += sig.connect(lambda: print('hello ', end=''))
world += sig.connect(lambda: print('world'))

sig() # hello world

# let's remove hello slot

hello.disconnect()

sig() # world

# here's another way to remove a slot

sig -= world

# or...

del world

# Node: The above `del` relies on the garbage collector, which is not fully reliable.

Reactive

Reactive variables are paired with an on_change signal.

x = Reactive(1)

x += lambda x: print('x is now', x)

x(2)  # This is sets to 2 and will print: "x is now 2"

# Inc/Dec operators of non-callable values are forwarded to enclosed value:

x += 1 # "x is now 3"

Lazy

Lazy values are functions that are called only when the value is needed


equation = Lazy(lambda: 2 * math.pi)
equation() # computed!
equation() # value is returned again, since it has already been computed

Both reactive and lazy values can depend on each other and be chained.

x = Reactive(2)
y = Reactive(3)
equation = Lazy(lambda: x() + y(), [x, y])

equation() # 5 (computed and cached)
equation() # 5 (return cached value)

x(1) # set x to 1, invalidating the equation

equation() # 4 (recomputes since it was invalidated)

Work-in-progress features

These features are incomplete so they are lacking documentation right now.

Reactive properties

player.team = ReactiveProperty('red')
player.team += lambda team: print('Player switched to', team)
player.team = 'blue' # 'Player switch to blue'

Reactive classes

Reactive methods

Reactive vectors


# set underlying type for colors, must have r,g,b accessors
Rvec.Type = glm.vec3

# XYZ
point = Rvec(1, 1, 1)

# print contents on change
point += lambda p: print(p.x, p.y, p.z)

# changing an individual property now fires change listeners
point.x = 100

Reactive colors


# RGB
rgb = Rcolor(1, 1, 1)

# print contents on change
rgb += lambda c: print(c.r ,c.g, c.b)

# changing an individual property now fires change listeners
rgb.r = .5

flipcoder / pythonic-reactive