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digitalmars.D.learn - opEquals code generation

reply drug <drug2004 bk.ru> writes:
I iterate over struct members and check against equality depending on 
member type. is there more simple/cleaner/better way to achieve this 
functionality? Especially without string mixins?
Sep 19 2017
next sibling parent drug <drug2004 bk.ru> writes:
19.09.2017 15:01, drug пишет:

 I iterate over struct members and check against equality depending on 
 member type. is there more simple/cleaner/better way to achieve this 
 functionality? Especially without string mixins?


oops, https://run.dlang.io/is/PbZE5i
Sep 19 2017
prev sibling parent reply Steven Schveighoffer <schveiguy yahoo.com> writes:
On 9/19/17 8:01 AM, drug wrote:

 I iterate over struct members and check against equality depending on 
 member type. is there more simple/cleaner/better way to achieve this 
 functionality? Especially without string mixins?


Why not just use tupleof directly instead of having to find the member 
name and using mixins?

-Steve
Sep 19 2017
parent reply drug <drug2004 bk.ru> writes:
19.09.2017 15:38, Steven Schveighoffer пишет:

 On 9/19/17 8:01 AM, drug wrote:

 I iterate over struct members and check against equality depending on 
 member type. is there more simple/cleaner/better way to achieve this 
 functionality? Especially without string mixins?


 
 Why not just use tupleof directly instead of having to find the member 
 name and using mixins?
 
 -Steve


Hmm, I'm sure I had tried it before and failed, but now I've managed to 
do so and it's really simpler (https://run.dlang.io/is/GJkokW):
```
auto opEquals()(auto ref const(typeof(this)) rhs)
     {
         import std.math : approxEqual, isNaN;
         import std.traits : isFloatingPoint, isIntegral;

         static foreach(i; 0..this.tupleof.length)
         {
             {
                 alias FType = typeof(this.tupleof[i]);

                 // a field of this structure
                 auto tf = this.tupleof[i];
                 // a field of other structure
                 auto of = rhs.tupleof[i];

                 static if (isFloatingPoint!FType)
                 {
                     if (!tf.isNaN || !of.isNaN)
                     {
                         if (!approxEqual(tf, of))
                             return false;
                     }
                 }
                 else static if (isIntegral!FType)
                 {
                     if (tf != of)
                         return false;
                 }
                 else
                     static assert (0);
             }
         }
         return true;
     }
```

Thank you, Steven!
Sep 19 2017
parent reply Neia Neutuladh <neia ikeran.org> writes:
On Tuesday, 19 September 2017 at 13:18:04 UTC, drug wrote:

 19.09.2017 15:38, Steven Schveighoffer пишет:

 On 9/19/17 8:01 AM, drug wrote:

 I iterate over struct members and check against equality 
 depending on member type. is there more simple/cleaner/better 
 way to achieve this functionality? Especially without string 
 mixins?


 
 Why not just use tupleof directly instead of having to find 
 the member name and using mixins?
 
 -Steve


 Hmm, I'm sure I had tried it before and failed, but now I've 
 managed to do so and it's really simpler


Could be a bit simpler than that, depending on your needs:

bool opEquals(Object other) const nothrow  nogc
{
     auto f = cast(typeof(this)) other;
     if (f is null) return false;
     return this.tupleof == other.tupleof;
}
Sep 19 2017
parent Steven Schveighoffer <schveiguy yahoo.com> writes:
On 9/19/17 4:28 PM, Neia Neutuladh wrote:


 Could be a bit simpler than that, depending on your needs:
 
 bool opEquals(Object other) const nothrow  nogc
 {
      auto f = cast(typeof(this)) other;
      if (f is null) return false;
      return this.tupleof == other.tupleof;
 }


That doesn't compare floating point in the way he wants.

-Steve
Sep 19 2017