auto osmData = datastream.take(size).array;
datastream.popFrontN(size);
auto header = BlobHeader(osmData);
http://he-the-great.livejournal.com/49636.html
How do I know if popFrontN is needed? If I was given a value
base range then it is. If I was given a reference range (in its
many forms) the extra call to popFrontN will result in an
unneeded data jump. I could require that a forward range is
passed in, then I can save() before calling .array and thus
always require popFrontN.
The best option is probably to use the RefRange wrapper, but it
does create an annoying element of surprise.
Yes. I agree. It's good example of problem. I just had problem
like this with *take* function, *startsWith* and others. So we
have two kinds of ranges: with reference and value semantics. But
both of them could be of reference or value *types* (struct or
class). So how would we determine at CT (by generic algorithms)
wheter current range has ref or value semantics (we couldn't just
rely on testing if it's class or struct)!? I think it's
important, because it can make influence on programme logic. And
again I want to say that we must explicitly say (in doc) that we
have two logical range categories, so new users would not make
stupid mistakes. Also unittests would be good for ref and value
ranges to illustrate our intentions.
