The review of std.hash package

[deadalnix]

Le 08/08/2012 11:49, Walter Bright a écrit :
> On 8/8/2012 1:44 AM, Johannes Pfau wrote:
>> Am Tue, 07 Aug 2012 17:39:15 -0700
>> schrieb Walter Bright <newshound2 at digitalmars.com>:
>>
>>> On 8/7/2012 10:39 AM, Dmitry Olshansky wrote:
>>>> std.hash.hash is a new module for Phobos defining an uniform
>>>> interface for hashes and checksums. It also provides some useful
>>>> helper functions to deal with this new API.
>>>
>>> The hash functions must use a Range interface, not a file interface.
>>>
>>> This is extremely important.
>>
>> I guess this is meant as a general statement and not specifically
>> targeted at my std.hash proposal?
>
> Both.
>
>> I'm a little confused as all hashes already are OutputRanges in my
>> proposal. It's probably not explicit enough in the documentation, but
>> it's mentioned in one example and in the documentation for 'put';
>
> It should accept an input range. But using an Output Range confuses me.
> A hash function is a reduce algorithm - it accepts a sequence of input
> values, and produces a single value. You should be able to write code like:
>
> ubyte[] data;
> ...
> auto crc = data.crc32();
>
> For example, the hash example given is:
>
> foreach (buffer; file.byChunk(4096 * 1024))
> hash.put(buffer);
> auto result = hash.finish();
>
> Instead it should be something like:
>
> auto result = file.byChunk(4096 * 1025).joiner.hash();
>
> The magic is that any input range that produces bytes could be used, and
> that byte producing input range can be hooked up to the input of any
> reducing function.
>
> The use of a member finish() is not what any other reduce algorithm has,
> and so the interface is not a general component interface.
>
> I know the documentation on ranges in Phobos is incomplete and confusing.
>
> I appreciate the effort and care you're putting into this.
>

That is a really good point. +1