• via Digitalmars-d-bugs (41/41) Nov 12 2014 https://issues.dlang.org/show_bug.cgi?id=13724

via Digitalmars-d-bugs <digitalmars-d-bugs puremagic.com> writes:

https://issues.dlang.org/show_bug.cgi?id=13724

          Issue ID: 13724
           Summary: std.datetime.timeIt
           Product: D
           Version: D2
          Hardware: x86
                OS: Windows
            Status: NEW
          Severity: enhancement
          Priority: P1
         Component: Phobos
          Assignee: nobody puremagic.com
          Reporter: bearophile_hugs eml.cc

I suggest to add to Phobos a very simple function like this timeIt:


import std.stdio, std.datetime, std.typecons;

ulong fibonacci(uint n) {
    if (n == 0 || n == 1)
        return 1;
    else
        return fibonacci(n - 1) + fibonacci(n - 2);
}

auto timeIt(Callable)(lazy Callable f) {
    StopWatch sw;
    sw.start;
    auto result = f();
    sw.stop;
    return tuple(result, sw.peek.nsecs / 1_000_000_000.0);
}

void main() {
    37.fibonacci.timeIt.writeln;
}



Output (the second item of the tuple is always in seconds):

Tuple!(ulong, double)(39088169, 2.38505)


The point of this function is to have something very quick and easy to use (so
no configuration arguments, and nothing complex to remember) to time a function
while you write code. For more refined performance testing other things should
be used. This function is useful because it has a minimal cognitive burden and
minimal code to be used.

It's very similar to the Timing function of Mathematica, that is used often:
http://reference.wolfram.com/language/ref/Timing.html

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