Macro shades::sw

macro_rules! sw {
    ($e:expr, . $a:tt) => { ... };
    ($e:expr, . $a:tt . $b:tt) => { ... };
    ($e:expr, . $a:tt . $b:tt . $c:tt) => { ... };
    ($e:expr, . $a:tt . $b:tt . $c:tt . $d:tt) => { ... };
}

Swizzle macro.

This macro allows to swizzle expressions to yield expressions reorganizing the vector attributes. For instance, sw!(color, .rgbr) will take a 4D color and will output a 4D color for which the alpha channel is overridden with the red channel.

The current syntax allows to extract and construct from a lot of types. Have a look at Swizzlable for a comprehensive list of what you can do.