On Monday, 5 June 2023 at 13:57:20 UTC, Ki Rill wrote:
How do I generate `setX` methods for all private mutable
variables in my class? Do I need to use `__traits`?
I need this for my
[tiny-svg](https://github.com/rillki/tiny-svg) project to
generate `setX` methods for all Shapes.
Example:
```D
class Rectangle {
private immutable ...;
private Color fillColor;
private Color strokeColor;
private uint strokeWidth;
this(int x, int y) {...}
mixin(???);
// I need this:
Rectangle setFillColor(Color color) {...}
Rectangle setStrokeColor(Color color) {...}
Rectangle setStrokeWidth(uint color) {...}
}
```
Usage:
```D
new Rectangle(10, 10)
.setFillColor(Colors.white)
.setStrokeColor(Colors.black)
.setStrokeWidth(3);
```
You need to put an user attribute on the fieldd then to use
static introspection to generate the setters.
Very basically that works like that
```d
enum Set;
class Color {}
auto generateSetters(T)()
{
string result;
import std.traits;
static foreach (m; __traits(allMembers, T))
{{
alias member = __traits(getMember, T, m);
static if (hasUDA!(member, Set))
result ~= "void set" ~ m ~ "(" ~
typeof(member).stringof ~ "){}\n";
}}
return result;
}
class Rectangle {
@Set private Color fillColor;
@Set private Color strokeColor;
@Set private uint strokeWidth;
mixin(generateSetters!(Rectangle)());
}
void main()
{
with (new Rectangle) {
setstrokeWidth(0);
setstrokeColor(null);
setfillColor(null);
}
}
```
although I did not spent time on the setter body... I suppose the
question was more about the metprogramming technic, and that you
don't want a pre-mashed solution ;)
