Improving import handling in VS Code

General
,
1

Based on the reasoning from @anthony and @cocreature have a custom prelude is not such a good idea. It could easily be misused, could be hard to follow.

I guess the real issue here is to manually import things.

DAML Studio already has a feature that offers import of types, functions. This is fantastic! However, it seems it works only for “built-in” types, modules, e.g. Optional, functions in DA.Action etc.

Can we improve this in the way that this works for types, modules in the current project as well?

1 Like
2

Trying to ascertain I understand this correctly (I don’t use VSCode much myself). Is the issue that:

  1. When trying to autocomplete an import statement, the VSCode extension only suggests packages from the stdlib, and should in addition suggest packages from all (data-)dependencies, or that
  2. When you use a function from a stdlib module you have not imported, the extension automatically suggests adding the import and can do it as a quickfix, and you would like that to also work for all modules in (data-)dependencies?

Or both?

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3

I thought of the second one. The first one would be just nice to have for me, not that important.

Typical use case for example is that I type somewhere in the code fromOptional. Now VSCode highlights it with error if it’s not important, I can hit Cmd/Ctrl + . and the IDE offers to import the missing function.

This is a production booster for me.

1 Like
4

Hi Tamas,

I was trying to reproduce in the process of writing the issue, and the behaviour I am observing does not seem to match your description. Would you mind helping me understand where I’m going wrong?

If my DAML project consists entirely of this Main.daml file:

module Main where

setup : Scenario ()
setup = scenario do
  let x : Int = fromOptional 0 $ Some 4
  debug $ show x

I do not get any useful auto-import suggestion. If, however, my file looks like (note the existing import):

module Main where
import DA.Optional ()

setup : Scenario ()
setup = scenario do
  let x : Int = fromOptional 0 $ Some 4
  debug $ show x

then I do get a suggestion to add fromOptional to the list of imports for the DA.Optional module. Is this the feature you were referring to?

If so, at least on my machine (using 1.4.0-snapshot.20200722.4796.0.28ab504b), if I make a 2-file project with MyLib.daml as

module MyLib where

fun : Int -> Int
fun x = x + 1

and Main.daml as

module Main where
import MyLib ()

setup : Scenario ()
setup = scenario do
  let x = fun 3
  debug $ show x

I do get the suggestion to automatically add fun to the import list of MyLib, just like with the built-in library DA.Optional.

Is this different from what you observe? Am I misunderstanding what feature you were referring to?

1 Like
5

Hm, this is quite interesting. Trying out your example VSCode only offered import fromRational which is strange.

Because I was certain it offered me fromOptional the way I described I started to play with it. If you add an import for instance to DA.Assert then all of a sudden fromOptional appears in the suggested imports. E.g.:

import DA.Assert ((===))

setup : Scenario ()
setup = scenario do
  let x : Int = fromOptional 0 $ Some 4
  debug $ show x

Apparently it seems any module from DA would make this work, i.e. having an import for DA.List or DA.Functor. See the attached screenshot.

autoimport
autoimport840×490 103 KB

I tried having an empty import list as you suggested, like import DA.Optional (). That works, however it’s a bit inconvenient in my mind, as I have to add it manually. I do admit that it does help if I do not want a whole module, but specific functions, and after one manual step I get auto import.

6

Also, I think this thread about the imports is worth having while the original discussion about prelude is not. Can we split the topic somehow? :thinking:

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7

Moved, let me know if this works, feel free to edit the title if you think it can be more specific.

2 Likes
8

Hi Tamas,

I can reproduce, but it seems so weird I can’t imagine this is the intended behaviour. I’ll have to let someone who knows a bit more about how our autocomplete is implemented, and what the intended behaviour was, chime in.

1 Like