Haskell的含义是什么？

Question

I'm trying to understand an example from plotlyhs :

plotly "div6"
    [points (aes & x .~ sepalLength 
                 & y .~ sepalWidth
                 & color ?~ (fromEnum . irisClass)) iris]
    & layout . margin ?~ thinMargins
    & layout . height ?~ 300

But I don't know what & means. Also I can't quite seem to google it.

I don't know what .~ or ?~ mean, either, but I guess I ask other questions for those.

Answer 1

More than likely, you're using the reverse function application operator , defined as

(&) :: a -> (a -> b) -> b
a & f = f a

It's simply a flipped version of ($) , frequently used in GUI libraries and other things where it makes sense to "apply" features and modifiers to existing values.

textbox & onClick foo & enabled

looks better and is often more straightforward than

enabled . onClick foo $ textbox

which reads backwards, in some sense. To know what the line is about, you have to start from the right.