I’m trying to work out if there’s a nicer way (i.e. more clever) of using lens-aeson to set a key based on the value of another key.
I have a YAML structure like this:
yaml' :: Value
yaml' =
[yamlQQ|
- panda:
x-image: panda
- goat:
x-image: goat
|]
that I want to transform into this:
yaml' :: Value
yaml' =
[yamlQQ|
- panda:
image: panda:latest
x-image: pada
- goat:
image: goat:latest
x-image: goat
|]
That is, I want to add/set the value of image based on the value of x-image of the same object.
The way I came up with was to write a helper function
foo o = o & _Object . at "image" ?~ String (iN <> ":latest")
where
iN = o ^. key "x-image" . _String
and using that I can do what I want:
λ> yaml' & values . members %~ foo
Array [Object (fromList [("panda",Object (fromList [("image",String "panda:latest"),("x-image",String "panda")]))]),Object (fromList [("goat",Object (fromList [("image",String "goat:latest"),("x-image",String "goat")]))])]
Is there another, nicer way of doing this?