buffered input

[Robert Jacques]

On Sun, 06 Feb 2011 23:01:12 -0500, Andrei Alexandrescu  
<SeeWebsiteForEmail at erdani.org> wrote:

> On 2/6/11 10:59 PM, Robert Jacques wrote:
>> On Sun, 06 Feb 2011 21:47:48 -0500, Torarin <torarind at gmail.com> wrote:
>>
>>> 2011/2/7 Robert Jacques <sandford at jhu.edu>:
>>>> On Sun, 06 Feb 2011 10:43:47 -0500, Andrei Alexandrescu
>>>> <SeeWebsiteForEmail at erdani.org> wrote:
>>>>
>>>>> On 2/6/11 6:01 EST, Tomek Sowiński wrote:
>>>>>>
>>>>>> Nick Sabalausky napisał:
>>>>>>
>>>>>>> discard and fetch?
>>>>>>
>>>>>> I like that.
>>>>>
>>>>> What's missing is the part that they refer to front. Maybe
>>>>> discardFromFront() and fetchToFront()? But then I like
>>>>> discardFromFront()
>>>>> and appendToFront() better - the latter is about as long and more
>>>>> informative.
>>>>>
>>>>> Don't forget that these are relatively rarely used.
>>>>>
>>>>>
>>>>> Andrei
>>>>>
>>>>
>>>> Actually, I don't think these functions would be relatively rarely
>>>> used. I
>>>> don't see that many people using a buffered input's popFront. Instead
>>>> I see
>>>> shiftFront in its place and an appendToFront call has to be made
>>>> whenever
>>>> buffer.front.empty.
>>>>
>>>
>>> Why not popFront if empty?
>>
>> Because even reading UTF-8 requires more than 1-byte of information.
>> Basically, any routine that processes a raw stream is going to have to
>> handle the case where what they're processing straddles the buffer
>> boundary. Now, if the routine wraps the raw stream in some higher-order
>> range, such as byLine, which guarantees them that none of their inputs
>> straddle, great. But it would be negligent to neglect those coders
>> writing the higher-level ranges.
>
> They aren't being neglected. If you need to get more stuff in the  
> current unit of work, use appendToFront().
>
> Let's restart this. What do you want to do that you can't do with the  
> proposed API?
>
> Andrei

Nothing. I like the API and it makes things like byChunk actually usable  
in my mind. My objection was to your 'relatively rarely used' comment and  
the implications of that with regard to API design. I have also just  
realized that made a typo when talking about appendToFront; I meant a call  
to appendToFront would be common when your working slice of .front has run  
out, but you're not ready to call shiftFront (because you're in the middle  
of parsing something, etc). The way I stated it, a call to popFront and a  
call to appendToFront would be (mostly) equivalent. Which may has confused  
people. Sorry.