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109 lines
1.9 KiB
Lua
109 lines
1.9 KiB
Lua
--[=[
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@c ArrayIterable x Iterable
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@mt mem
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@d Iterable class that contains objects in a constant, ordered fashion, although
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the order may change if the internal array is modified. Some versions may use a
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map function to shape the objects before they are accessed.
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]=]
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local Iterable = require('iterables/Iterable')
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local ArrayIterable, get = require('class')('ArrayIterable', Iterable)
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function ArrayIterable:__init(array, map)
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self._array = array
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self._map = map
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end
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function ArrayIterable:__len()
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local array = self._array
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if not array or #array == 0 then
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return 0
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end
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local map = self._map
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if map then -- map can return nil
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return Iterable.__len(self)
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else
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return #array
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end
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end
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--[=[@p first * The first object in the array]=]
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function get.first(self)
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local array = self._array
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if not array or #array == 0 then
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return nil
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end
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local map = self._map
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if map then
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for i = 1, #array, 1 do
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local v = array[i]
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local obj = v and map(v)
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if obj then
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return obj
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end
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end
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else
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return array[1]
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end
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end
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--[=[@p last * The last object in the array]=]
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function get.last(self)
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local array = self._array
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if not array or #array == 0 then
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return nil
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end
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local map = self._map
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if map then
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for i = #array, 1, -1 do
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local v = array[i]
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local obj = v and map(v)
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if obj then
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return obj
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end
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end
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else
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return array[#array]
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end
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end
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--[=[
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@m iter
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@r function
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@d Returns an iterator for all contained objects in a consistent order.
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]=]
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function ArrayIterable:iter()
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local array = self._array
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if not array or #array == 0 then
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return function() -- new closure for consistency
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return nil
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end
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end
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local map = self._map
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if map then
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local i = 0
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return function()
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while true do
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i = i + 1
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local v = array[i]
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if not v then
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return nil
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end
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v = map(v)
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if v then
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return v
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end
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end
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end
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else
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local i = 0
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return function()
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i = i + 1
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return array[i]
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end
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end
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end
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return ArrayIterable
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