On Sat, 06 Oct 2012 04:07:41 -0400, monarch_dodra <[email protected]>
wrote:
On Saturday, 6 October 2012 at 05:24:06 UTC, Steven Schveighoffer
wrote:
On Fri, 05 Oct 2012 11:15:44 -0400, monarch_dodra
<[email protected]> wrote:
However, I that the "isOutputRange" definition should require
infinite-ness, as mentioned by others.
No, this is very wrong. A slice is an output range, but is finite.
A slice is an input range and can safely be used as such. What is
the merit of *also* defining it as an output range? Why even
bother with defining "OutputRange" if it just means "InputRange"
+ "functions"?
try doing this on a unix system
cat /dev/zero > ~/zeros
And see if the output file zeros is infinite :)
Even an appender is finite when you run out of memory.
Do you think output files make bad output ranges, even though they are
finite?
An output range is nothing but an interface to a storage location.
Whether the storage location is infinite or not is up to the location, the
output range has to support both infinite and finite targets.
What you are proposing would make it illegal to use std.algorithm.copy on
*any* memory-based construct, or else have it blissfully succeed by
throwing away any extra data. Neither of these situations are tenable.
If you are putting something that is larger into something that is
smaller and cannot be extended, I would expect an error. You don't?
Yes, but as shown the semantics of "put" are basically: "Cram
*anything* you want inside of me. I can take it".
No, definitely not. An output range can take input, but must obviously be
able to say "I'm full".
As evidenced by my two examples, this is clearly not the case,
and, even worse, the developer has _no way_ of knowing this.
I'm not against defining a standard way to say "I'm full", but proposing
it *can't* say that is not the solution. Clearly, we could do better in
defining a standard way to test for fullness (full property akin to
empty?). Even so, putting into a non-full range could generate an error.
However, I really don't like having a range tell me "yeah, I'm an Output
Range", just to choke on the first call to put.
What about an input range that is immediately empty? These are corner
cases, but certainly valid.
-Steve
