2,875
edits
Module:FunList/Iterators: Difference between revisions
Add SelectEnumerator
No edit summary |
(Add SelectEnumerator) |
||
| Line 16: | Line 16: | ||
function Enumerator:moveNext() | function Enumerator:moveNext() | ||
error('Not implemented in base class.') | |||
end | |||
function Enumerator:getEnumerator() | |||
error('Not implemented in base class.') | error('Not implemented in base class.') | ||
end | end | ||
| Line 42: | Line 46: | ||
function TableEnumerator.new(tbl) | function TableEnumerator.new(tbl) | ||
local self = setmetatable(Enumerator.new(), TableEnumerator) | local self = setmetatable(Enumerator.new(), TableEnumerator) | ||
self. | self.tbl = tbl | ||
return self | return self | ||
end | end | ||
function TableEnumerator:moveNext() | function TableEnumerator:moveNext() | ||
if self.state == 0 then | |||
self.state = 1 | |||
end | |||
-- Grab the next index for the internal table. | -- Grab the next index for the internal table. | ||
local key = self.index | local key = self.index | ||
key = next(self. | key = next(self.tbl, key) | ||
self.index = key | self.index = key | ||
-- If the index exist, we have succesfuly moved to the next. | -- If the index exist, we have succesfuly moved to the next. | ||
if key ~= nil then | if key ~= nil then | ||
self.current = self. | self.current = self.tbl[key] | ||
return true | return true | ||
end | end | ||
return false | return false | ||
end | |||
function TableEnumerator:getEnumerator() | |||
if self.state == 0 then | |||
return self | |||
else | |||
return TableEnumerator.new(self.tbl) | |||
end | |||
end | |||
-- SELECT ENUMERATOR -- | |||
local SelectEnumerator = setmetatable({}, { __index = Enumerator }) | |||
SelectEnumerator.__index = SelectEnumerator | |||
SelectEnumerator.__pairs = Enumerator_mt.__pairs | |||
function SelectEnumerator.new(source, selector) | |||
local self = setmetatable(Enumerator.new(), TableEnumerator) | |||
self.state = 0 | |||
self.source = source | |||
self.selector = selector | |||
self.enumerator = nil | |||
self.position = 0 | |||
return self | |||
end | |||
function SelectEnumerator:moveNext() | |||
if self.state == 0 then | |||
self.state = 1 | |||
self.position = 0 | |||
self.enumerator = self.source:getEnumerator() | |||
end | |||
if self.state == 1 then | |||
local enumerator = self.enumerator | |||
if enumerator:moveNext() == true then | |||
local sourceElement = enumerator.current | |||
self.position = self.position + 1 | |||
self.current = selector(sourceElement, self.position) | |||
return true | |||
end | |||
end | |||
return false | |||
end | |||
function SelectEnumerator:getEnumerator() | |||
if self.state == 0 then | |||
return self | |||
else | |||
return SelectEnumerator.new(self.source, self.selector) | |||
end | |||
end | end | ||