What are the best std algo for testing a range implementation ?
monarch_dodra via Digitalmars-d-learn
digitalmars-d-learn at puremagic.com
Tue May 27 04:43:11 PDT 2014
On Tuesday, 27 May 2014 at 10:50:54 UTC, BicMedium wrote:
> Let's say I have a set of containers, using a
> D-unfriendly-semantic. They rather use a kind of ADA vocabulary
> (according to https://en.wikipedia.org/wiki/Deque). I want to
> make them "range-aware".
>
> If the input/output ranges are easy to implement(so it's just
> reading/writing an element, keeping an index for the writer and
> another for the reader, and reseting it, isn't it ? So if
> (isInputRange!MyCont && isOutputRange!MyCont) then it's a
> "Deque", right ?).
> The bidirectionnal ranges or the forward ranges become more
> difficult to interpret with the idioms I
> use(Insert,Add,Remove)...Is this a kind of 3rd plane ("time":
> "return to previous state", "make a backup": copy/roll-back -
> undo/redo ?)
Just keep in mind that a container is not a range. A container is
an object that can hold items, and you can add and remove items
from said object. The Range is a way to iterate your container.
For example, a range definitely does NOT make insertion, removals
or duplactes of your items. You can "save" a range, but that's
NOT the same thing as making a duplicate of your container that
you can roll back.
I'd suggest you take a look at std.container.array to see what
I'm talking about.
> Could you recommend me the algos from std.algo to test
> efficiently my implementations ? (example, if you want to be
> sure that the input ranges work then you'd use this...if you
> want to be sure that output ranges work then you'd use that
> ...Some kind of "reference" unit tests ?). At the present time,
> each time I try one I get rejected by the template
> constraints...
If the algos are turning you down, then you must have missed
something. Check that:
alias Range = YourRangeTypeHere;
static assert(isInputRange!Range);
static assert(isForwardRange!Range);
static assert(isBidirectionalRange!Range);
static assert(hasLength!Range);
static assert(isRandomAccessRange!Range);
static assert(hasSlicing!Range);
At the *very least*, the first 3 should pass for a deque. The 3
others depend on what primitives you want to offer.
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