2,875
edits
Module:FunList/Iterators: Difference between revisions
Add SelectManyEnumerator
No edit summary |
(Add SelectManyEnumerator) |
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| Line 163: | Line 163: | ||
else | else | ||
return WhereEnumerator.new(self.source, self.predicate) | return WhereEnumerator.new(self.source, self.predicate) | ||
end | |||
end | |||
-- WHERE ENUMERATOR -- | |||
local SelectManyEnumerator = setmetatable({}, { __index = Enumerator }) | |||
SelectManyEnumerator.__index = SelectManyEnumerator | |||
SelectManyEnumerator.__pairs = Enumerator_mt.__pairs | |||
function SelectManyEnumerator.new(source, selector) | |||
local self = setmetatable(Enumerator.new(), SelectManyEnumerator) | |||
self.state = 0 | |||
self.source = source | |||
self.selector = selector | |||
self.position = 0 | |||
self.enumerator = nil -- Enumerator of the source Enumerable | |||
self.sourceEnumerator = nil -- Enumerator of the nested Enumerable | |||
return self | |||
end | |||
function SelectManyEnumerator:moveNext() | |||
while true do | |||
-- Setup state | |||
if self.state == 0 then | |||
self.position = 0 | |||
self.enumerator = self.source:getEnumerator() | |||
self.state = -3 -- signal to get (first) nested enumerator | |||
end | |||
-- Grab next value from nested enumerator | |||
if self.state == -4 then | |||
if self.sourceEnumerator:moveNext() then | |||
self.current = self.sourceEnumerator.current | |||
self.index = self.sourceEnumerator.index | |||
self.state = -4 -- signal to get next item | |||
return true | |||
else | |||
self.state = -3 -- signal to get next enumerator | |||
end | |||
end | |||
-- Grab nest nested enumerator | |||
if self.state == -3 then | |||
if self.enumerator:moveNext() then | |||
local current = self.enumerator.current | |||
self.position = self.position + 1 | |||
local sourceTable = self.selector(current, self.position) | |||
-- We need to turn the nested table into an enumerator | |||
self.sourceEnumerator = TableEnumerator.new(sourceTable):getEnumerator() | |||
self.state = -4 -- signal to get next item | |||
else | |||
-- enumerator doesn't have any more nested enumerators. | |||
return false | |||
end | |||
end | |||
end | |||
end | |||
function SelectManyEnumerator:getEnumerator() | |||
if self.state == 0 then | |||
return self | |||
else | |||
return SelectManyEnumerator.new(self.source, self.predicate) | |||
end | end | ||
end | end | ||
| Line 170: | Line 234: | ||
TableEnumerator = TableEnumerator, | TableEnumerator = TableEnumerator, | ||
SelectEnumerator = SelectEnumerator, | SelectEnumerator = SelectEnumerator, | ||
WhereEnumerator = WhereEnumerator | WhereEnumerator = WhereEnumerator, | ||
SelectManyEnumerator = SelectManyEnumerator | |||
} | } | ||