Vote for the new std.hash (oops, std.digest)

[Manu]

On 26 August 2012 16:43, Johannes Pfau <nospam at example.com> wrote:

> Am Sun, 26 Aug 2012 13:19:35 +0300
> schrieb Manu <turkeyman at gmail.com>:
>
> > Looks good, though one thing annoys me as always throughout the D
> > docs, liberal use of auto can make them very difficult to understand.
> >
> > auto result = hash.finish();
> >
> > >From the examples where this appears, I have absolutely no idea what
> > 'result' could possibly be and what I can do with it, and you're
> > forcing me to go and dig further for that information (waste of time).
> > Surely there would be no harm in just writing the type there for
> > clarity?
> >
> > <rant>
> > I'd personally like to see auto abolished, or at least heavily
> > discouraged for the sake of clarity from code examples throughout the
> > docs. I'm constantly having to chase up what auto's may resolve to
> > when reading examples >_<
> > You may argue this demonstrated un-idiomatic code, and my trouble is
> > due to inexperience; I ask, who is most likely to be reading docs?
> >
>
> OK, I'll fix this if std.digest is accepted into phobos.
>
> However, in this example auto is not just used for convenience, it has
> an actual use case:
>
> As documented here
>
> http://dl.dropbox.com/u/24218791/d/phobos/std_digest_digest.html#ExampleDigest
> (finish method) the type returned by finish can differ between different
> hash implementations. It's always a static array of ubyte, but for crc
> it's ubyte[4] for sha1 it's ubyte[20] and for md5 it's ubyte[16]. So
> in templated methods, auto is more generic than hardcoding a type. The
> equivalent to auto is using digestType!Digest, so
>
> auto result = hash.finish();
> digestType!(typeof(hash)) result = hash.finish();
>
> are equivalent. But
>
> ubyte[4] result = hash.finish();
>
> does only work if hash is a CRC32 digest. It does not work for md5, sha1
> digests, etc.
>
> But I agree that examples are easier to read without auto, so I'll
> change them to use the explicit type where possible.
>

Case in point, look how much information you just gave us that is
completely obscured by 'auto' :)
My suggestion, simplify the example, or, at least the example associated
with the direct function documentation:

 auto md5   = digest!MD5(  "The quick brown fox jumps over the lazy dog");
 auto sha1  = digest!SHA1( "The quick brown fox jumps over the lazy dog");
 auto crc32 = digest!CRC32("The quick brown fox jumps over the lazy dog");

Those autos can be ubyte[n].
Though that said, looking at the API doc for finish(), it appears to return
a dynamic array, not a static array as you say... so ubyte[] could be used
everywhere, and that would be nice and clear?
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