Nix <nix version>
Type :? for help.

nix-repl> :l pretty-print-idempotent.nix
Added <number omitted> variables.

nix-repl> oneDeep
{ homepage = "https://example.com"; }

nix-repl> oneDeep
{ homepage = "https://example.com"; }

nix-repl> twoDeep
{
  layerOne = { ... };
}

nix-repl> twoDeep
{
  layerOne = { ... };
}

nix-repl> oneDeepList
[ "https://example.com" ]

nix-repl> oneDeepList
[ "https://example.com" ]

nix-repl> twoDeepList
[
  [ ... ]
]

nix-repl> twoDeepList
[
  [ ... ]
]