Module:FunList/Iterators
From Melvor Idle
Documentation for this module may be created at Module:FunList/Iterators/doc
-- BASE ENUMERATOR CLASS --
--enumerable = {}
local Enumerator = {}
local Enumerator_mt = {
__index = Enumerator,
__pairs = function(t) return t:overridePairs() end,
--__ipairs = function(t) return t:overrideiPairs() end
}
function Enumerator.new()
local self = setmetatable({}, Enumerator_mt)
self.current = nil
self.index = nil
return self
end
function Enumerator:moveNext()
error('Not implemented in base class.')
end
-- Hooks the moveNext function into the Lua 'pairs' function
function Enumerator:overridePairs()
self.index = nil
self.current = nil
local function iterator(t, k)
if self:moveNext() == true then
return self.index, self.current
end
return nil, nil
end
return iterator, self, nil
end
-- TABLE ENUMERATOR CLASS --
-- This is essentially a wrapper for the table object,
-- since it provides no state machine esque iteration out of the box
local TableEnumerator = setmetatable({}, { __index = Enumerator })
TableEnumerator.__index = TableEnumerator
TableEnumerator.__pairs = Enumerator_mt.__pairs
function TableEnumerator.new(tbl)
local self = setmetatable(Enumerator.new(), TableEnumerator)
self.data = tbl
return self
end
function TableEnumerator:moveNext()
-- Grab the next index for the internal table.
local key = self.index
key = next(self.data, key)
self.index = key
-- If the index exist, we have succesfuly moved to the next.
if key ~= nil then
self.current = self.data[key]
return true
end
return false
end
return {
Enumerator = Enumerator,
TableEnumerator = TableEnumerator
}