Comprehension lists

[manuel-rubio]

As a good Erlanger, I like the possibility to perform this kind of action. I know that it's like a shortcut for something we could do with list.map/2 and list.filter/2, but I think that's very expressive and convenient.

It could be implemented in the Erlang way:

[ car || car <- cars, car.country == "DE" ]

or it could be implemented in the Elixir (and almost Python) way:

for car <- cars if car.country == "DE" { car }

what do you think?

[lpil]

In Gleam we avoid having multiple ways to do things, and comprehensions don't enable the programmer to do anything new, so I don't think they would be a high value addition.

Having said that, you can achieve the same effect with use expressions.

let pairs = {
  use x <- list.flat_map(xs)
  use y <- list.map(ys)
  #(x, y)
}