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Contents
module React
alias CellValue = Int32
abstract class Cell
@dependents = [] of ComputeCell
def initialize(initial : CellValue)
@value = initial
end
getter :value
protected getter :dependents
end
class InputCell < Cell
def value=(new_value : CellValue)
@value = new_value
@dependents.each(&.propagate)
@dependents.each(&.fire_callbacks)
end
end
class ComputeCell < Cell
alias CallbackID = Int32
@callbacks_given = 0
@callbacks = {} of CallbackID => CellValue ->
@last_callback_value : CellValue
def initialize(input : Cell, &compute : CellValue -> CellValue)
initialize(->{ compute.call(input.value) }, input)
end
def initialize(input1 : Cell, input2 : Cell, &compute : (CellValue, CellValue) -> CellValue)
initialize(->{ compute.call(input1.value, input2.value) }, input1, input2)
end
private def initialize(@new_value : -> CellValue, *dependencies : Cell)
super(@new_value.call)
@last_callback_value = @value
dependencies.each { |i| i.dependents << self }
end
def add_callback(&block : CellValue ->) : CallbackID
@callbacks_given += 1
@callbacks[@callbacks_given] = block
@callbacks_given
end
def remove_callback(id : CallbackID)
@callbacks.delete(id)
end
protected def propagate
new_value = @new_value.call
return if new_value == @value
@value = new_value
@dependents.each(&.propagate)
end
protected def fire_callbacks
return if @value == @last_callback_value
@last_callback_value = @value
@callbacks.each_value { |c| c.call(@value) }
@dependents.each(&.fire_callbacks)
end
end
end
Version data entries
396 entries across 396 versions & 1 rubygems