Module:FunList/Iterators: Difference between revisions
From Melvor Idle
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local Enumerator_mt = { | local Enumerator_mt = { | ||
__index = Enumerator, | __index = Enumerator, | ||
__pairs = function(t) return t:overridePairs()end | __pairs = function(t) return t:overridePairs() end, | ||
__ipairs = function(t) return t:overrideiPairs() end | |||
} | } | ||
Line 18: | Line 19: | ||
end | end | ||
function Enumerator:moveINext() | |||
error('Not implemented in base class.') | |||
end | |||
-- Hooks the moveNext function into the Lua 'pairs' function | |||
function Enumerator:overridePairs() | function Enumerator:overridePairs() | ||
local function iterator(t, k) | local function iterator(t, k) | ||
if self:moveNext() == true then | if self:moveNext() == true then | ||
return self.index, self.current | return self.index, self.current | ||
end | end | ||
return nil, nil | |||
end | end | ||
self.index = nil | |||
self.current = nil | |||
return iterator, self, nil | return iterator, self, nil | ||
end | |||
-- Hooks the moveNext function into the Lua 'ipairs' function | |||
function Enumerator:overrideiPairs() | |||
local function iterator(t, k) | |||
if self:moveINext() == true then | |||
return self.index, self.current | |||
end | |||
return nil, nil | |||
end | |||
self.index = 0 | |||
self.current = nil | |||
return iterator, self, self.index | |||
end | end | ||
Line 51: | Line 70: | ||
-- If the index exist, we have succesfuly moved to the next. | -- If the index exist, we have succesfuly moved to the next. | ||
if key then | if key ~= nil then | ||
self.current = self.data[key] | self.current = self.data[key] | ||
return true | |||
end | |||
return false | |||
end | |||
function TableEnumerator:moveINext() | |||
self.index = self.index + 1 | |||
self.current = self.data[self.index] | |||
if self.current ~= nil then | |||
return true | return true | ||
end | end |
Revision as of 15:43, 21 July 2024
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
function Enumerator:moveINext()
error('Not implemented in base class.')
end
-- Hooks the moveNext function into the Lua 'pairs' function
function Enumerator:overridePairs()
local function iterator(t, k)
if self:moveNext() == true then
return self.index, self.current
end
return nil, nil
end
self.index = nil
self.current = nil
return iterator, self, nil
end
-- Hooks the moveNext function into the Lua 'ipairs' function
function Enumerator:overrideiPairs()
local function iterator(t, k)
if self:moveINext() == true then
return self.index, self.current
end
return nil, nil
end
self.index = 0
self.current = nil
return iterator, self, self.index
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
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
function TableEnumerator:moveINext()
self.index = self.index + 1
self.current = self.data[self.index]
if self.current ~= nil then
return true
end
return false
end
return {
Enumerator = Enumerator,
TableEnumerator = TableEnumerator
}