[phobos] Proposal of StopWatch module

[SHOO]

(2010/08/21 5:04), Andrei Alexandrescu wrote:
> I think the code is ready for prime time, modulo the issues below. What
> do you all think?
>
> Overall this is a good example of modern, idiomatic D code. Everything
> is clear, simple, and in the right place. Congratulations, Shoo!
>
> *******
>

> Line 80: You could an assert or even an enforce here for TICKSPERSPEC.
>

A program does not work at all when a function failed in a module 
constructor. I'll set 0 for TICKSPERSEC when a function failed.
And, had better I make TICKSPERSEC -> TicksPerSec?


 > Line 737: I'm afraid you can't put @trusted here because you don't know
 > the safety level of BaseFunc and TargetFunc. You'll need to use @system.
 >

This is a source of worry very much.
I hit on the idea that manage to do:

private @safe void dummySafeFunc(alias FN)()
{
	FN();
}

template isSafe(alias FN)
{
	enum isSafe = is(typeof({dummySafeFunc!(FN)();}()));
}
@safe
ComparingBenchmarkReturnValue comparingBenchmark(
     alias baseFunc, alias targetFunc, int CNT = 0xfff)()
     if (isSafe!baseFunc && isSafe!targetFunc)
{
....
}

@system
ComparingBenchmarkReturnValue comparingBenchmark(
     alias baseFunc, alias targetFunc, int CNT = 0xfff)()
     if (!(isSafe!baseFunc && isSafe!targetFunc))
{
....
}

It is dirty slightly...

May I put isSafe in std.traits?


> Line 21: please add a comment that you're adding this "import inside
> struct" curiosity with an experimental purpose only.
>
> Line 99: I'm a bit worried that we allow toSeconds for all integer
> widths. Probably if (isIntegral!T && T.sizeof >= 4) would be better.
>
> Line 170: same concern about toMilliseconds - even bigger because there
> are lots more milliseconds out there :o).
>
> Line 197: the parameter name should be msec
>
> Line 218: same discussion about the allowed integral types
>
> Line 245: parameter name
>
> Line 431: "Unused"
>
> Line 469: typedef is deprecated (sorry). That's partly why I'm
> suggesting to go with the enum.
>
> Line 739: Since the two aliases are actually functions, you may want to
> start their names with lowercase.
>

I see.

> Line 762: Beautiful idiom!
>

Thanks! But, I want to write like this:
with (measureTime!((a){assert(a.seconds);}))
{
     doSomething();
}

I don't want to name a nonuse variable.
In this usage, I think that With is proper.
But, this doesn't call destructor. (for bug 3516?
Though I think that how to use is free.