Destructuring records into custom variable names - elm

Question

Consider this function:
mix : Color -> Color -> Color
mix c1 c2 =
let
{ red, green, blue, alpha } = toRgb c1
{ red, green, blue, alpha } = toRgb c2
in
...
The above won't work because it's introducing duplicate variable names. Is it possible to destructure the above values into r1, r2, g1, g2, etc?
For clarification, toRgb has this signature:
toRgb : Color -> { red:Int, green:Int, blue:Int, alpha:Float }
A hypothetical syntax might express better what I'd like to do:
mix : Color -> Color -> Color
mix c1 c2 =
let
{ red as r1, green as g1, blue as b1, alpha as a1 } = toRgb c1
{ red as r2, green as g2, blue as b2, alpha as a2 } = toRgb c2
in
...

Answer 1

I had trouble figuring out if this was possible and realized that field accessors are so powerful that it didn't matter.
Presumably your code might look something like:
mix : Color -> Color -> Color
mix c1 c2 =
{ red = avg c1.red c2.red
, green = avg c1.green c2.green
, blue = avg c1.blue c2.blue
, alpha = avg c1.alpha c2.alpha
}
Not so terrible or unreadable. BUT, you could even do something like:
mix : Color -> Color -> Color
mix c1 c2 =
{ red = avg .red c1 c2
, green = avg .green c1 c2
, blue = avg .blue c1 c2
, alpha = avg .alpha c1 c2
}
Are those worse than:
mix : Color -> Color -> Color
mix c1 c2 =
let
{ red1, green1, blue1, alpha1 } = toRgb c1
{ red2, green2, blue2, alpha2 } = toRgb c2
in
{ red = avg red1 red2
, green = avg green1 green2
, blue = avg blue1 blue2
, alpha = avg alpha1 alpha2
}

Answer 2

EDIT:
I did not realize Color is part of Core, so I edit.
You can destruct Record with property names.
In case of having multiple values, then you have to have some helper.
Following example, I defined toTuple to do that.
import Color exposing (Color)
toTuple {red, green, blue, alpha}
= (red, green, blue, alpha)
mix : Color -> Color -> Color
mix c1 c2 =
let
(r1, g1, b1, a1) = toTuple <| Color.toRgb c1
(r2, g2, b2, a2) = toTuple <| Color.toRgb c2
in
Color.rgba
(avg r1 r2)
(avg g1 g2)
(avg b1 b2)
(avgf a1 a2)
avg i j = (i + j) // 2
avgf p q = 0.5 * (p + q)
Original:
I'm not sure this is what you are looking for but, you do not need to convert it to record.
case of allows you to pattern match via constructor function. e.g.
type Color = RGB Int Int Int
purple = RGB 255 0 255
printRedVal =
case purple of
RGB r g b -> text (toString r)