Revised RFC on range design for D2

[Bill Baxter]

On Fri, Sep 12, 2008 at 11:22 PM, Sergey Gromov <snake.scaly at gmail.com> wrote:
> Bill Baxter <wbaxter at gmail.com> wrote:
>> But I do have some suggestions nonetheless!  Marked with ==> below.
>>
>> -- Universal --
>> r.done
>> r.init
>>
>> --- Input : Universal ---
>> e=r.head
>> e=r.next
>> r1=r.release  ==> r.transfer?  Release sounds like ref counting (e.g. in COM)
>>                           Also seems like r.transfer(r1) could make
>> implementation more efficient.
>>                           Or perhaps make it a .swap like STL.  Maybe
>> you have something against .swap?
>>
>> -- Output : Universal --
>> r.put(e)
>>
>> -- Forward : Input, (optional) Output  --
>> r1 = r
>> r.head = e
>> t=r.after(s)
>>
>> -- Bidirectional : Forward --
>> e = r.toe
>> r.toe = e
>> r.reduce           ==> r.retreat  -- aka "pull back"
>> t = r.before(s)
>>
>> -- Random access : Bidirectional --
>> l = r.length
>> e = r[n]
>> r[n] = e
>> r1 = r[n1..n2]
>> ------------
>>
>> Just those two!
>
> I've got a bit of insight!  XD
>
> -- Common
> r.empty
>
> -- InOut
> v = r.next;     => T R.next();
> r.next = v;     => T R.next(T v);
>
> -- Forward: InOut, copyable
> v = r.tip
> r.tip = v
> r1 = r.before(s)
> r1 = r.after(s)
>
> -- Bidir: Forward
> v = r.prev
> r.prev = v
> v = r.toe
> r.toe = v
>
> -- Random: Bidir
> no changes
>
> prev() seems very misleading, otherwise I like it.
>

So basically you changed
done ==> empty
head ==> tip
retreat ==> prev
?

I'm actually ok with either "done" or "empty".  "Done" is weird on a
random access range, but "empty" is weird on file input range, or a
generator.  Or on the HMM example which is "done" when it reaches an
end state, but is not really "empty".

"head to toe" is a perfectly common expression, at least in American
English.  Not sure why you don't like it.  But tip to toe is kinda
cool for being 1 less letter!  And no less clear.

"prev" is horrible.  I still like "retreat" best so far.  We need the
contrapositive of "next" not the "opposite".  :-)  And since that
doesn't exist we should just go for a word that sorta means the right
thing and won't be  confused with being the opposite (or with being
something else entirely like "reduce").

--bb