What is the most proper way to add org modules?

[Anton-Latukha]

Description

Spacemacs has a specially crafted structure for Org-mode.

I want to clarify a question to solve for me and others in a doc/PR about this.

Officially by org-mode - additional (especially official) extensions to org-mode recommended to be installed by extending the org-modules list.
I asked a question on Gitter, and recieved some responses, as also found my own, but nothing really solid.
I what to clarify what is the most proper way to add official org modules to extend org-mode from the org layer.

---

Also good to have some input to maybe open other issue/PR. Default org-modules list has many modules enabled by default:

(org-w3m org-bbdb org-bibtex org-docview org-gnus org-info org-irc org-mhe org-rmail org-eww)

And most of them probably not used by many if not majority people that use Spacemacs. Browsers AFAIK in Spacemacs not in great shape.
Probably it can be right to allow people to populate org-modules from the ground-up.

Reproduction guide 🪲

• Start Emacs
  Wonder what is the proper way to add org-habit to extend org layer.

Observed behaviour: 👀 💔
Declare installation of org-habit after the initialization of org layer.

Expected behaviour: ❤️ 😄
Something beautiful. Like:

(org :variables
  org-modules '(
    org-habit
    org-capture
    org-id
    org-protocol
    org-brain
    )
)

System Info 💻

• OS: gnu/linux
• Emacs: 26.1
• Spacemacs: 0.300.0
• Spacemacs branch: develop (rev. 95422ae)
• Graphic display: t
• Distribution: spacemacs
• Editing style: vim
• Completion: helm

[agzam]

Modules have to be extended, not in prescriptive manner like you suggesting using :variables. Simply doing something like this should work (add-to-list 'org-modules 'org-tempo t).

[Anton-Latukha]

1. On every module - Emacs runs an add-to-list expression that adds a single element (by default to the beginning of the list).
2. Official org-mode documentation states to add new entries to the end of the list. So if respect that - indeed add-to-list ... t to append to the end.

I did:

require 'org
(nconc org-modules
       '(
         org-capture
         org-habit
         org-id
         org-protocol
         org-brain
         )) 

It is one invocation and code easily readable/modefiable. nconc in this form adds values to the back, back to the referred list.

But I want to know is I am doing the completely right thing regarding Spacemacs org layer.

[michaelherold]

This is what I'm using in a private layer:

# packages.el
(with-eval-after-load 'org
  (add-to-list 'org-modules 'org-habit t))

[github-actions]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Please let us know if this issue is still valid!

[Anton-Latukha]

Basically I got sure that Org packages just need to be loaded, there is no need to declare them as modules explicitly.