Lambdas in for-each loops

[Maurizio Cimadamore]

On 05/09/12 15:02, Remi Forax wrote:
> On 09/05/2012 03:55 PM, Sergey Kuksenko wrote:
>> On 09/05/2012 05:51 PM, Remi Forax wrote:
>>> On 09/05/2012 03:26 PM, Brian Goetz wrote:
>>>>> At such case I have a serious question - why for-each loop doesn't
>>>>> allow
>>>>> to use Iterator? Why do we need only Iterable (and arrays of course) ?
>>>>> May be it may sense to expand for-each loop itself and detach the
>>>>> problem from lambda? it looks like we something like project
>>>>> Coin2.0 for
>>>>> such things.
>>>> This was a hot issue during the development of the foreach loop. In
>>>> the end, the EG decided that allowing Iterator in foreach loop was
>>>> potentually confusing, since as a side effect of being iterated, the
>>>> iterator was "drained".
>>>>
>>>>
>>> Also, you can write horrible things like,
>>>    Iterator<String> it = collection...
>>>    for(String s: it) {   // ok, simple loop
>>>     if (...) {
>>>        ...
>>>        it.remove();   // not a simple loop anymore
>>>      }
>>>    }
>>>
>>> if you read the code, a foreach loop should always be a simple loop
>>> with no side effect on the iterable.
>>>
>>> Rémi
>>>
>> Ok. Let's do:
>>
>>    Iterator<String> it = collection...
>>    for(String s: asIterable(it) /*or lambda*/) {   // ok, simple loop
>>     if (...) {
>>        ...
>>        it.remove();   // not a simple loop anymore
>>      }
>>    }
>>
>> I see the same.
>>
> No, because the header of your loop is not simple anymore.
> BTW, that's why I prefer the lambda syntax, because you add syntax 'noise',
> the lambda or the method reference, to the foreach loop,
> so the fact that's it's a not a plain old loop is clearly visible.
>
> for(String s: getACollection()) {  // simple loop
> }
>
> for(String s: () -> getAnIterator()) {  // not a simple loop
> }
>
> As a writer, you pay a syntactic price (burger arrow?) in order to warn
> the reader.
>
> Rémi
>
>
I think that's a weak argument - what about:

List<String> ls = new ArrayList<>();
ls.add("Hello");
ls.add("World!");
for (String s : ls) {
     if (true) { ls.remove("World!"); }
}


Simple or not simple?

Maurizio