Making alias of a struct field needs "this".

[Stanislav Blinov]

On Tuesday, 2 June 2020 at 09:28:01 UTC, realhet wrote:

> I did it that way:
>   private enum fieldMap = [ // simple names for descriptive and 
> structured fields
>     "hauteur"       : "general.height",
>     "rayon"         : "profile.radius",
>     "plage"         : "profile.plage",
>     "offsetv"       : "profile.verticalOffset",
>     "offseth"       : "profile.horizontalOffset",
>     "varrad0"       : "profile.linearVariationBottom",
>     "varrad1"       : "profile.linearVariationTop",
>     "amplitude"     : "periphery.amplitude",
>     "varlin0"       : "periphery.linearVariationBottom",
>     "varlin1"       : "periphery.linearVariationTop",
>     "varsinp"       : "periphery.cosinusVariationPlage",
>     "varsino"       : "periphery.cosinusVariationOffset",
>     "periodes"      : "periphery.nbPeriods",
>     "revolution"    : "periphery.turn"
>   ];
>
>   static foreach(k, v; fieldMap){ mixin("@property auto $() 
> const{ return #; }".replace("$", k).replace("#", v)); } //I 
> know, i know -> AliasSeq :D
>
> But it doesn't look nice.

Try UDAs instead of a map:

struct A {
     struct G {
         @("hauteur") int height;
     }
     struct P {
         @("rayon")   int radius;
         @("plage")   int plage;
         @("offsetv") int verticalOffset;
         @("offseth") int horizontalOffset;

         int noShortcut;

         @("varrad0") int linearVariationBottom;
     }

     G general;
     P profile;
     /* ... */
     static foreach (i, m; typeof(this).tupleof)
         static foreach (j, f; typeof(m).tupleof)
             static if (__traits(getAttributes, f).length)
                 mixin("@property auto ", __traits(getAttributes, 
f)[0], "() const { return this.tupleof[i].tupleof[j]; }");
}

pragma(msg, __traits(allMembers, A));