Complex types formatting

[wojtekmach]

Currently it's only broken on |, and so e.g. on complex structs it looks like this:

(https://hexdocs.pm/ecto/Ecto.Changeset.html#t:t/0)

Ideally, we'd get back something similar to what formatter can do:

iex> IO.puts Code.format_string!("t() :: %Ecto.Changeset{action: action, changes: %{optional(atom) => term}, constraints: [constraint], data: Ecto.Schema.t | map | nil, empty_values: term, errors: [{atom, error}], filters: %{optional(atom) => term}, params: %{optional(String.t) => term} | nil, prepare: [(t -> t)], repo: atom | nil, repo_opts: Keyword.t, required: [atom], types: nil | %{optional(atom) => Ecto.Type.t}, valid?: boolean, validations: Keyword.t}")
t() :: %Ecto.Changeset{
  action: action,
  changes: %{optional(atom) => term},
  constraints: [constraint],
  data: Ecto.Schema.t() | map | nil,
  empty_values: term,
  errors: [{atom, error}],
  filters: %{optional(atom) => term},
  params: %{optional(String.t()) => term} | nil,
  prepare: [(t -> t)],
  repo: atom | nil,
  repo_opts: Keyword.t(),
  required: [atom],
  types: nil | %{optional(atom) => Ecto.Type.t()},
  valid?: boolean,
  validations: Keyword.t()
}

[josevalim]

Yeah, we can start using the formatter if it available but we may lose cross linking. -- *José Valimwww.plataformatec.com.br <http://www.plataformatec.com.br/>Founder and Director of R&D*

[wojtekmach]

Yup, bringing in formatter without auto linking is pretty trivial. To have it both ways though: do you think it should be approached from the angle of parsing ast or constructing some special algebra docs or something entirely different?

[josevalim]

@wojtekmach no idea. We may be able to do this:

1. Convert the AST with Macro.to_string and convert each function we want to link to a unique id. For example, autolink_1, autolink_2. The result is AST as a string and a map with function names (autolink1 and friends) as keys and the link as values.

2. Format the result if the formatter is available

3. Use a regex to convert function names back to autolinks.

[wojtekmach]

@josevalim brilliant, that should work. autolinkX is definitely a good start. Possible next step to consider is to have these unique ids have the same length as the identifiers that they're replacing so that formatter works as if on the real thing. Generating such ids should be fine for long identifiers, but for short identifiers it's easy to get a conflict so I'm thinking that some weird unicode code points could be used there :)

Edit: I'd like to give it a shot sometime next week

[wojtekmach]

@josevalim so far so good, stay tuned!

[josevalim]

Generating such ids should be fine for long identifiers, but for short identifiers it's easy to get a conflict so I'm thinking that some weird unicode code points could be used there

I think we can go with a minimum and that should be fine for most purposes as the nesting doesn't need to be exact. Maybe just a bunch of ts followed by a number with a minimum of 3 ts (it doesn't need to be t, you get the idea). :)

The end result looks great btw.

[wojtekmach]

yup, I ended up making placeholders in the form of _p000_ for now :)