[phobos] Split std.datetime in two?

[Andrei Alexandrescu]

On 2/11/11 1:52 PM, spir wrote:
> On 02/11/2011 08:20 PM, Steve Schveighoffer wrote:
>> At some point, factoring out repetitive code becomes more harmful than
>> the alternative. I feel like unit tests are one of those cases.
>
> Hum, had a similar thought recently. I started to "unfactor out" some
> pieces of code into very basic caller funcs (the kind that constantly
> get called, thus would appear on top of a profiler's output in terms of
> number of executions). The initial reason was lack of knowledge about
> whether the tool funcs would be inlined or not (reason for the other
> thread).
> Then, I realised the result is sometimes easier to understand, provided
> the initially factored out part is properly "titled" by a comment,
> especially when it is non-obvious to identify as a kind of sub-task.

Consider the code below. It is a simplification of 60 lines of code in 
std.datetime, which I paste at the end of this message. The code is 
formatted at 80 columns, at the same time showing that you can write 
compact _and_ good _and_ simple _and_ effective code in 80 columns. (It 
wraps in the email because email wraps at 75 columns or so.)

The space taken is 24/60 lines = 40%. Less than half of the original - 
all with generous indentation and narrow columns. Clarity greatly 
gained, bulk saved, maintenance simplified, failure clarified, and your 
shoes are shiny. "What else can we do?" Really if there's any debate 
that this is not a huge improvement I give up. Behead me.

     unittest
     {
         auto badDates =
             [
                 "", "990704", "0100704", "2010070", "2010070 ",
                 "120100704", "-0100704", "+0100704", "2010070a", 
"20100a04",
                 "2010a704", "99-07-04", "010-07-04", "2010-07-0", 
"2010-07-0 ",
                 "12010-07-04", "-010-07-04", "+010-07-04", "2010-07-0a",
                 "2010-0a-04", "2010-a7-04", "2010/07/04", "2010/7/04",
                 "2010/7/4", "2010/07/4", "2010-7-04", "2010-7-4", 
"2010-07-4",
                 "99Jul04", "010Jul04", "2010Jul0", "2010Jul0 ", 
"12010Jul04",
                 "-010Jul04", "+010Jul04", "2010Jul0a", "2010Jua04", 
"2010aul04",
                 "99-Jul-04", "010-Jul-04", "2010-Jul-0", "2010-Jul-0 ",
                 "12010-Jul-04", "-010-Jul-04", "+010-Jul-04", 
"2010-Jul-0a",
                 "2010-Jua-04", "2010-Jal-04", "2010-aul-04", "2010-07-04",
                 "2010-Jul-04",
             ];

         foreach (badDate; badDates)
         {
             assertThrown!DateTimeException(Date.fromISOString(badDate),
                 "Accepts bad date: " ~ badDate);
         }
     }


Andrei

P.S. Original code:

     unittest
     {
         version(testStdDateTime)
         {
             assertThrown!DateTimeException(Date.fromISOString(""));
             assertThrown!DateTimeException(Date.fromISOString("990704"));
             assertThrown!DateTimeException(Date.fromISOString("0100704"));
             assertThrown!DateTimeException(Date.fromISOString("2010070"));
             assertThrown!DateTimeException(Date.fromISOString("2010070 "));
 
assertThrown!DateTimeException(Date.fromISOString("120100704"));
             assertThrown!DateTimeException(Date.fromISOString("-0100704"));
             assertThrown!DateTimeException(Date.fromISOString("+0100704"));
             assertThrown!DateTimeException(Date.fromISOString("2010070a"));
             assertThrown!DateTimeException(Date.fromISOString("20100a04"));
             assertThrown!DateTimeException(Date.fromISOString("2010a704"));

             assertThrown!DateTimeException(Date.fromISOString("99-07-04"));
 
assertThrown!DateTimeException(Date.fromISOString("010-07-04"));
 
assertThrown!DateTimeException(Date.fromISOString("2010-07-0"));
 
assertThrown!DateTimeException(Date.fromISOString("2010-07-0 "));
 
assertThrown!DateTimeException(Date.fromISOString("12010-07-04"));
 
assertThrown!DateTimeException(Date.fromISOString("-010-07-04"));
 
assertThrown!DateTimeException(Date.fromISOString("+010-07-04"));
 
assertThrown!DateTimeException(Date.fromISOString("2010-07-0a"));
 
assertThrown!DateTimeException(Date.fromISOString("2010-0a-04"));
 
assertThrown!DateTimeException(Date.fromISOString("2010-a7-04"));
 
assertThrown!DateTimeException(Date.fromISOString("2010/07/04"));
 
assertThrown!DateTimeException(Date.fromISOString("2010/7/04"));
             assertThrown!DateTimeException(Date.fromISOString("2010/7/4"));
 
assertThrown!DateTimeException(Date.fromISOString("2010/07/4"));
 
assertThrown!DateTimeException(Date.fromISOString("2010-7-04"));
             assertThrown!DateTimeException(Date.fromISOString("2010-7-4"));
 
assertThrown!DateTimeException(Date.fromISOString("2010-07-4"));

             assertThrown!DateTimeException(Date.fromISOString("99Jul04"));
             assertThrown!DateTimeException(Date.fromISOString("010Jul04"));
             assertThrown!DateTimeException(Date.fromISOString("2010Jul0"));
             assertThrown!DateTimeException(Date.fromISOString("2010Jul0 
"));
 
assertThrown!DateTimeException(Date.fromISOString("12010Jul04"));
 
assertThrown!DateTimeException(Date.fromISOString("-010Jul04"));
 
assertThrown!DateTimeException(Date.fromISOString("+010Jul04"));
 
assertThrown!DateTimeException(Date.fromISOString("2010Jul0a"));
 
assertThrown!DateTimeException(Date.fromISOString("2010Jua04"));
 
assertThrown!DateTimeException(Date.fromISOString("2010aul04"));

 
assertThrown!DateTimeException(Date.fromISOString("99-Jul-04"));
 
assertThrown!DateTimeException(Date.fromISOString("010-Jul-04"));
 
assertThrown!DateTimeException(Date.fromISOString("2010-Jul-0"));
 
assertThrown!DateTimeException(Date.fromISOString("2010-Jul-0 "));
 
assertThrown!DateTimeException(Date.fromISOString("12010-Jul-04"));
 
assertThrown!DateTimeException(Date.fromISOString("-010-Jul-04"));
 
assertThrown!DateTimeException(Date.fromISOString("+010-Jul-04"));
 
assertThrown!DateTimeException(Date.fromISOString("2010-Jul-0a"));
 
assertThrown!DateTimeException(Date.fromISOString("2010-Jua-04"));
 
assertThrown!DateTimeException(Date.fromISOString("2010-Jal-04"));
 
assertThrown!DateTimeException(Date.fromISOString("2010-aul-04"));

 
assertThrown!DateTimeException(Date.fromISOString("2010-07-04"));
 
assertThrown!DateTimeException(Date.fromISOString("2010-Jul-04"));
         }
     }