26da50ab0e
@kha I've added iterator.extract : iterator -> iterator -> option string It returns `none` if the iterators are "incompatible". If this function is inconvenient to use, we can change it and return the empty string in these cases. Given iterators `it1` and `it2`, if they are sharing the same string object in memory, then the cost is O(pos(it2) - pos(it1)). If not, we have an extra O(N) step where we check whether the strings being iterated by it1 and it2 are equal (`N` is the size of the strings). In most applications, I believe the iterators will share the string object. I didn't test the code much. BTW, I found an unrelated bug at vm_string.cpp. So, I'm not very confident this code is rock solid.
12 lines
118 B
Text
12 lines
118 B
Text
"abc"
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(some "a")
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(some "")
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none
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(some "abc")
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(some "bcde")
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(some "abcde")
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(some "ab")
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none
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none
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(some "a")
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(some "a")
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