SysTime in a Struct

[Ali Çehreli]

On 03/01/2012 03:46 PM, albatroz wrote:

 > Hi Ali, just tring to define a type that holds this information. It was
 > just an attempt to create a type DateTime with the values from the known
 > strings, I thought it was possible to create the definition directly in
 > the Struct, with no need for an external function.
 > edate and etime are strings that I will read in to the struct, but for
 > operations with time and dates I need to create/define a DateTime type.

 From that description, it looks like you can hold edate etc. as members 
and produce SysTime as needed. The following demonstrates how to convert 
preEv to SysTime by opCast implicitly and by sys_time explicitly:

import std.stdio;
import std.conv;
import std.datetime;

struct preEv
{
     string edate; //010112
     string etime; //00:00:00
     string etext; //

     SysTime opCast(T : SysTime)() const
     {
         return SysTime(DateTime(
                            Clock.currTime.year,
                            to!int(this.edate[2..4]),
                            to!int(this.edate[0..2]),
                            to!int(etime[0..2]),
                            to!int(etime[3..5]),
                            to!int(etime[6..8])));
     }

     SysTime sys_time() const @property
     {
         return to!SysTime(this);
     }
}

void main()
{
     auto pe = preEv("010312", "15:53:00", "The event");

     // Explicit conversion
     auto st0 = to!SysTime(pe);
     writeln(st0);

     // Casting
     auto st1 = cast(SysTime)(pe);
     writeln(st1);

     // As a property
     auto st2 = pe.sys_time;
     writeln(st2);
}

If you think that you need to cache SysTime in the object itself, you 
can do that for example in opCast.

On the other hand, if all you need to store is SysTime and etext, then 
you need to create SysTime in the constructor:

import std.stdio;
import std.conv;
import std.datetime;

struct preEv
{
     SysTime time;
     string etext;

     this (string edate, string etime, string etext)
     {
         this.time = SysTime(DateTime(
                                 Clock.currTime.year,
                                 to!int(edate[2..4]),
                                 to!int(edate[0..2]),
                                 to!int(etime[0..2]),
                                 to!int(etime[3..5]),
                                 to!int(etime[6..8])));
         this.etext = etext;
     }
}

void main()
{
     auto pe = preEv("010312", "15:53:00", "The event");

     writeln(pe.time);
}

Ali