Where to put user configurations/defaults for spacemacs?

Question

I am a vim user trying to covert to emacs/spacemacs, but I'm having a horribly difficult time configuring things that seem like a breeze others.

I want to limit the fill to 80 (mainly for .txt files and .org mode.. I thought the default was 80 anyway? Is this only for certain file extensions?), and I found this question which gives this line:

(setq-default fill-column 80)

but where do I put this?. I have tried putting it in init.el, the dotspacemacs/user-config section of my .spacemacs, and the dotspacemacs/user-init section of my .spacemacs. The keyboard combos C-u 80 C-x f work for setting the fill to 80 while I'm in the buffer, and M-q adjusts the fill if lines are overfilled.

Am I missing something here? From what I can see, this (dated) blog of a spacemacs contributor suggests placing such lines in dotspacemacs/user-config and not in init.el. Meanwhile, Eivind Fonn, another spacemacs contributor who has publicized his dotfiles on github, has everything in an init.el and no .spacemacs.

I should add that other statements such as (gobal-hl-line-mode) and (setq-default evil-escape-key-sequence "jk") work as expected for me. Do I have a big misunderstanding of how to configure spacemacs as my own or am I just mistaken on the intricacies of this specific function?

EDIT

I was mistaken on the command that I needed. I actually want auto-fill-mode instead of the default fill value. I tried putting

(auto-fill-mode 1)

in dotspacemacs/user-config and in dotspacemacs/user-init but neither work. If I simply execute it as a command, it works fine.

I decided to scrap spacemacs and start learning emacs with evil-mode from the ground up. If I put the (auto-fill-mode 1) into my ~/.emacs.d/init.el, it works fine. I even made a function that auto-enables this only in org-mode. Learning emacs from scratch has given me a much better understanding of how emacs works, but now that I am manually installing packages and configuring things on my own, I want all the pre-configured-ness of spacemacs back! So now my question is where do I put (auto-fill-mode 1) in my .spacemacs?

Version info:

OS: Ubuntu 14.04
Emacs: 24.4.2
Spacemacs: Develop Branch (Release 0.105.x)

Answer 1

setting default value for auto-fill-column

Normally, you'd put such configuration in dotspacemacs/user-config, which is a function in your dotfile (~/.spacemacs).

It's possible to use a ~/.spacemacs.d/init.el as your dotfile instead of ~/.spacemacs, which I assume is what Eivind Fond does.

The original default value for fill-column is 70. In current develop branch, Spacemacs configures fill-column to a default of 80, so you probably don't need to do it yourself.

As Kevin wrote in the comment, keep in mind that we only set the default value for fill-column, and the value can be different in buffers or modes that set their own value for fill-column. When the value is changed for a certain major-mode, it is usually done in the mode-hook. So if, for example, you want Org buffers to have a fill column of 72, you'd add something like this to dotpsacemacs/user-config:

(add-hook 'org-mode-hook (lambda () (setq fill-column 72)))

I've used a lambda, but I recommend using named functions instead of lambdas when you want to add them to hooks, since it makes it easier to use remove-hook later if necessary.

You might want to read the sections about buffer-local variables and hooks in the manual.

enabling auto-fill-mode

auto-fill-mode is a local mode, so when you add (auto-fill-mode 1) to your user-config, it activates auto-fill-mode only for the buffer that is current when that line is evaluated. Instead, you want to add auto-fill-mode to the hook of any major-mode where you want to activate auto-fill-mode. For example, if you want to activate auto-fill-mode in Org buffers, you need to add it the org-mode-hook:

(add-hook 'org-mode-hook #'auto-fill-mode)

If you want to activate auto-fill-mode everywhere, you'd probably want to hook it into text-mode-hook and prog-mode-hook. This way auto-fill-mode will be enabled in every major mode that derives from text-mode or from prog-mode, so basically that covers (almost?) every buffer where it's logical to have auto-fill-mode turned on:

(add-hook 'prog-mode-hook #'auto-fill-mode)
(add-hook 'text-mode-hook #'auto-fill-mode)

These lines should be placed in dotspacemacs/user-config as well.