Better assert's status? (Was: Proposal for std.path replacement)

[Jacob Carlborg]

On 2011-03-07 13:55, spir wrote:
> On 03/07/2011 07:20 AM, Jonathan M Davis wrote:
>> On Sunday 06 March 2011 21:57:30 Nick Sabalausky wrote:
>>> "Jonathan M Davis"<jmdavisProg at gmx.com> wrote in message
>>> news:mailman.2293.1299467610.4748.digitalmars-d at puremagic.com...
>>>
>>>> On Sunday 06 March 2011 18:08:49 Andrei Alexandrescu wrote:
>>>>> Yah, thing is people work on stuff they care about, not the most
>>>>> urgent
>>>>> stuff - surprise! :o) As such we don't have a ton of proposals for
>>>>> networking and xml, but we do have one (and I won't argue it's a bad
>>>>> one) for rehashing a module that basically worked.
>>>
>>> I'm not sure I'd say the current std.path "basically works", but I
>>> get what
>>> you mean.
>>>
>>>> I _was_ thinking of putting forward a new proposal which includes the
>>>> unit testing functionality that assertPred had which won't end up in an
>>>> improved
>>>> assert,
>>>
>>> Speaking of which: Now that assertPred has been rejected on the
>>> grounds of
>>> an improved assert that doesn't yet exist, what is the current status of
>>> the improved assert?
>>
>> There's an enhancement request for it:
>>
>> http://d.puremagic.com/issues/show_bug.cgi?id=5547
>>
>> I have no idea of any work is actually being done on it or not. It hasn't
>> actually been assigned to anyone yet, for whatever that's worth.
>> Honestly, it
>> wouldn't surprise me if it doesn't happen for a while. I'm not sure
>> that anyone
>> who is capable of doing it is particularly motivated to do it (though
>> I'm not
>> sure that they're _not_ either). It was clear that a number of people
>> wanted
>> assert to be smarter rather than having assertPred, but it isn't clear
>> that
>> assert is going to be made smarter any time soon. I suspect that it
>> will be a
>> while before it's done. We'll have to wait and see though.
>
> IIUC:
> The problem is this feature belongs to the category of things that
> cannot be implemented by any D programmer, in D, as a lib feature, even
> by an expert in the domain.
> It needs to get a representation of the unevaluated expression beeing
> asserted, meaning compiler support, meaning hard low-level C/++ and a
> great knowledge of the compiler architecture, esp the construction of
> the AST. If there was a way to "quote" D expressions, and get their
> representation at runtime, then we could do it ourselves (would imply
> some perf penalty, but I consider this worth compared to the terrible
> expressive power gained, and in fact totally neglectible for an assert
> statement).
> Please tell me where I'm wrong.
>
> With the same power, I would implement at once 'varWrite':
> int x = 3; s = square(x);
> varWrite("value: 'x' --> square: 's'");
> // --> "value: 3 --> square: 9"
> or even maybe:
> int x = 3;
> varWrite("value: 'x' --> square: 'x*x'");
> // --> "value: 3 --> square: 9"
>
>
> Denis

String mixins ?

-- 
/Jacob Carlborg