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fix bug and explain closure iterators better

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This commit is contained in:
flaviut 2014-07-18 18:53:03 -04:00
commit a868603482
1 changed files with 11 additions and 3 deletions
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content/for_iterators.md
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@ -84,7 +84,7 @@ $ nimrod c -r ./inline_iter.nim
## Closure Iterators ## Closure Iterators
Closure iterators hold on to their state and can be resumed at any time. The `finished()` function can be used to check if there are any more elements available in the iterator. Closure iterators hold on to their state and can be resumed at any time. The `finished()` function can be used to check if there are any more elements available in the iterator, however raw iterator usage is unintuitive and difficult to get right.
``` nimrod ``` nimrod
proc countTo(n: int): iterator(): int = proc countTo(n: int): iterator(): int =
@ -99,8 +99,16 @@ let countTo20 = countTo(20)
echo countTo20() echo countTo20()
var output = "" var output = ""
while not finished(countTo20): # Raw iterator usage:
output.add($countTo20() & " ") while true:
# 1. grab an element
let next = countTo20()
# 2. Is the element bogus? Its the end of the loop, discard it
if finished(countTo20):
break
# 3. Loop body goes here:
output.add($next & " ")
echo output echo output
output = "" output = ""