An IO Streams Library

[ikod via Digitalmars-d]

On Wednesday, 27 July 2016 at 06:18:07 UTC, Sönke Ludwig wrote:
> Am 26.07.2016 um 16:50 schrieb Johannes Pfau:
>> Am Mon, 25 Jul 2016 13:10:42 +0000
>>>
>>> Hello,
>>>
>>> I don't know if it is good practice or not, but sometimes it 
>>> make
>>> life easier if you can put part of the data back into the 
>>> input
>>> stream.
>>>
>>
>> Writing data back to a stream is quite uncommon. The standard 
>> way to
>> solve such problems is a peek method for buffered streams:
>>
>> auto buf = stream.peek(length)
>> // You can now look at the data in buf
>> stream.read() will still return the data read by peek, no need 
>> to write
>> data back into the stream.
>>
>
> With the notable exception of ungetc() for C's file streams. 
> But working on the byte level is something that ranges should 
> be used for in D's case and not streams, because the latter 
> tend to have a high call overhead. So such a feature could make 
> sense for a StreamInputRange/InputStreamRange wrapper.

Yes, and here is simple use-case for this: you have to process 
input stream of data chunks mixed with separators from the 
socket. To read only data and not separators, you can either ask 
stream code to "read until separator", or you can read as much as 
possible, then split on separator, return split-tail back to 
stream and process split-head. Now all your reads from stream 
will either start from the new data chunk or continue reading 
from it.

Of course, application code can manage all this on its own, but 
why not to help application programmer keep his code clean?