core: dotspacemacs-themes entries now accept package properties

It is now possible to use package properties like :location in
dotspacemacs-themes.

Added hooks ran at the beginning and end of configuration-layer/sync:
- configuration-layer-pre-sync-hook
- configuration-layer-post-sync-hook

configuration-layer-pre-sync-hook is used to hook the new function
spacemacs//add-theme-packages-to-additional-packages. This new function updates
dotspacemacs--additional-theme-packages variables.

Update documentation to mention the new feature.

core/core-configuration-layer.el

@@ -69,6 +69,12 @@ ROOT is returned."
              (dir (car (directory-files elpa-dir 'full pkg-match))))
         (when dir (file-name-as-directory dir))))))
 
+(defvar configuration-layer-pre-sync-hook nil
+  "Hook executed at the beginning of configuration synchronization.")
+
+(defvar configuration-layer-post-sync-hook nil
+  "Hook executed at the end of configuration synchronization.")
+
 (defvar configuration-layer-rollback-directory
   (concat spacemacs-cache-directory ".rollback/")
   "Spacemacs rollback directory.")
@@ -407,6 +413,7 @@ refreshed during the current session."
 (defun configuration-layer/sync (&optional no-install)
   "Synchronize declared layers in dotfile with spacemacs.
 If NO-INSTALL is non nil then install steps are skipped."
+  (run-hooks 'configuration-layer-pre-sync-hook)
   (dotspacemacs|call-func dotspacemacs/layers "Calling dotfile layers...")
   (setq dotspacemacs--configuration-layers-saved
         dotspacemacs-configuration-layers)
@@ -462,7 +469,8 @@ If NO-INSTALL is non nil then install steps are skipped."
   ;; configure used packages
   (configuration-layer//configure-packages configuration-layer--used-packages)
   (configuration-layer//load-layers-files configuration-layer--used-layers
-                                          '("keybindings.el")))
+                                          '("keybindings.el"))
+  (run-hooks 'configuration-layer-post-sync-hook))
 
 (defun configuration-layer/load-auto-layer-file ()
   "Load `auto-layer.el' file"
@@ -952,7 +960,7 @@ variable as well."
   "Read the additonal packages declared in the dotfile and create packages.
 USEDP if non-nil indicates that made packages are used packages."
   (dolist (pkg (append dotspacemacs-additional-packages
-                       dotspacemacs--additional-packages))
+                       dotspacemacs--additional-theme-packages))
     (let* ((pkg-name (if (listp pkg) (car pkg) pkg))
            (obj (configuration-layer/get-package pkg-name)))
       (if obj

core/core-dotspacemacs.el

@@ -100,9 +100,9 @@ wrapped in a layer. If you need some configuration for these
 packages then consider to create a layer, you can also put the
 configuration in `dotspacemacs/user-config'.")
 
-(defvar dotspacemacs--additional-packages '()
+(defvar dotspacemacs--additional-theme-packages '()
-  "Same as `dotspacemacs-additonal-packages' but reserved for Spacemacs
+  "Same as `dotspacemacs-additonal-packages' but reserved for themes declared
-internals.")
+in `dotspacemacs-themes'.")
 
 (defvar dotspacemacs-editing-style 'vim
   "One of `vim', `emacs' or `hybrid'.

core/core-spacemacs.el

@@ -104,8 +104,7 @@ the final step of executing code in `emacs-startup-hook'.")
                                     dotspacemacs-editing-style))
   (configuration-layer/initialize)
   ;; theme
-  (spacemacs/load-theme (car dotspacemacs-themes)
+  (spacemacs/load-default-theme spacemacs--fallback-theme)
-                             spacemacs--fallback-theme)
   ;; font
   (spacemacs|do-after-display-system-init
    ;; If you are thinking to remove this call to `message', think twice. You'll

core/core-themes-support.el

@@ -167,7 +167,7 @@ package name does not match theme name + `-theme' suffix.")
 (defvar spacemacs-post-theme-change-hook nil
   "Hook run after theme has changed.")
 
-(defun spacemacs/get-theme-package (theme)
+(defun spacemacs/get-theme-package-name (theme)
   "Returns the package theme for the given THEME name."
   (cond
    ;; built-in
@@ -178,63 +178,79 @@ package name does not match theme name + `-theme' suffix.")
    ;; fallback to <name>-theme
    (t (intern (format "%S-theme" theme)))))
 
+(defun spacemacs//get-theme-name (theme)
+  "Return the name of THEME."
+  (if (listp theme)
+      (car theme)
+    theme))
+
+(defun spacemacs/load-default-theme (&optional fallback-theme)
+  "Load default theme.
+Default theme is the car of `dotspacemacs-themes'.
+If FALLBACK-THEME is non-nil it must be a package name which will be loaded if
+THEME cannot be applied."
+  (spacemacs/load-theme (car dotspacemacs-themes) fallback-theme))
+
 (defun spacemacs/load-theme (theme &optional fallback-theme disable)
   "Apply user theme.
 If FALLBACK-THEME is non-nil it must be a package name which will be loaded if
 THEME cannot be applied.
 If DISABLE is non-nil then disable all previously applied themes before applying
 THEME."
-  (spacemacs//add-themes-to-additional-packages dotspacemacs-themes)
+  (let ((theme-name (spacemacs//get-theme-name theme)))
-  (condition-case err
+    (condition-case err
-      (progn
+        (progn
-        ;; Load theme
+          ;; Load theme
-        (unless (or (memq theme (custom-available-themes))
+          (unless (or (memq theme-name (custom-available-themes))
-                    (eq 'default theme))
+                      (eq 'default theme-name))
-          (let* ((pkg (spacemacs/get-theme-package theme))
+            (let* ((pkg-name (spacemacs/get-theme-package-name theme-name))
-               (pkg-dir
+                   (pkg-dir
-                (when pkg
+                    (when pkg-name
-                  (configuration-layer/get-elpa-package-install-directory
+                      (configuration-layer/get-elpa-package-install-directory
-                   pkg))))
+                       pkg-name))))
-            (when pkg-dir
+              (when pkg-dir
-              (add-to-list 'custom-theme-load-path pkg-dir)
+                (add-to-list 'custom-theme-load-path pkg-dir)
-              (when (or (eq 'moe-light theme)
+                (when (or (eq 'moe-light theme-name)
-                        (eq 'moe-dark theme))
+                          (eq 'moe-dark theme-name))
-                (load-file (concat pkg-dir "moe-light-theme.el"))
+                  (load-file (concat pkg-dir "moe-light-theme.el"))
-                (load-file (concat pkg-dir "moe-dark-theme.el"))))))
+                  (load-file (concat pkg-dir "moe-dark-theme.el"))))))
-        (when disable
+          (when disable
-          (mapc 'disable-theme custom-enabled-themes))
+            (mapc 'disable-theme custom-enabled-themes))
-        (eval `(spacemacs|do-after-display-system-init
+          (eval `(spacemacs|do-after-display-system-init
-                (load-theme ',theme t)))
+                  (load-theme ',theme-name t)))
-        (setq-default spacemacs--cur-theme theme)
+          (setq-default spacemacs--cur-theme theme-name)
-        (setq-default spacemacs--cycle-themes (cdr dotspacemacs-themes)))
+          (setq-default spacemacs--cycle-themes (cdr dotspacemacs-themes)))
-    ('error
+      ('error
-     (if fallback-theme
+       (if fallback-theme
-         ;; fallback to Spacemacs default theme
+           ;; fallback to Spacemacs default theme
-         (progn
+           (progn
-           (setq spacemacs--delayed-user-theme theme)
+             (setq spacemacs--delayed-user-theme theme-name)
-           (spacemacs/load-fallback-theme fallback-theme disable))
+             (spacemacs/load-fallback-theme fallback-theme disable))
-       ;; no fallback theme was specified, so we log explicit warning
+         ;; no fallback theme was specified, so we log explicit warning
-       (spacemacs-buffer/warning
+         (spacemacs-buffer/warning
-        (concat "An error occurred while applying "
+          (concat "An error occurred while applying "
-                "the theme \"%s\", fallback on theme \"%s\". \n"
+                  "the theme \"%s\", fallback on theme \"%s\". \n"
-                "Error was: %s") theme spacemacs--fallback-theme err)
+                  "Error was: %s")
-       (spacemacs-buffer/warning
+          theme-name spacemacs--fallback-theme err)
-        (concat "Please check the value of \"dotspacemacs-themes\" in your "
+         (spacemacs-buffer/warning
-                "dotfile or open an issue \n"
+          (concat "Please check the value of \"dotspacemacs-themes\" in your "
-                "so we can add support for the theme \"%s\".") theme)))))
+                  "dotfile or open an issue \n"
+                  "so we can add support for the theme \"%s\".")
+          theme-name))))))
 
 (defun spacemacs/load-fallback-theme (theme &optional disable)
   "Apply the fallback theme.
 If DISABLE is non-nil then disable all previously applied themes before applying
 THEME."
-  ;; pop up fallback theme to the top of the list
+  (let ((theme-name (spacemacs//get-theme-name theme)))
-  (setq spacemacs--cur-theme theme)
+    ;; pop up fallback theme to the top of the list
-  (setq dotspacemacs-themes (delq theme dotspacemacs-themes))
+    (setq spacemacs--cur-theme theme-name)
-  (add-to-list 'dotspacemacs-themes theme)
+    (setq dotspacemacs-themes (delq theme-name dotspacemacs-themes))
-  (when disable
+    (add-to-list 'dotspacemacs-themes theme-name)
-    (mapc 'disable-theme custom-enabled-themes))
+    (when disable
-  (eval `(spacemacs|do-after-display-system-init
+      (mapc 'disable-theme custom-enabled-themes))
-          (load-theme ',theme t))))
+    (eval `(spacemacs|do-after-display-system-init
+            (load-theme ',theme-name t)))))
 
 (defun spacemacs/cycle-spacemacs-theme ()
   "Cycle through themes defined in `dotspacemacs-themes.'"
@@ -267,11 +283,19 @@ has been changed to THEME."
   (interactive)
   (run-hooks 'spacemacs-post-theme-change-hook))
 
-(defun spacemacs//add-themes-to-additional-packages (themes)
+(defun spacemacs//add-theme-packages-to-additional-packages ()
-  "Add the THEMES packages to `dotspacemacs-additional-packages'."
+  "Add all theme packages from `dotspacemacs-themes' to packages to install."
-  (dolist (theme themes)
+  (setq dotspacemacs--additional-theme-packages nil)
-    (let ((pkg (spacemacs/get-theme-package theme)))
+  (dolist (theme dotspacemacs-themes)
-      (when pkg
+    (let* ((theme-name (spacemacs//get-theme-name theme))
-        (add-to-list 'dotspacemacs--additional-packages pkg)))))
+           (pkg-name (spacemacs/get-theme-package-name theme-name))
+           (theme2 (copy-tree theme)))
+      (when pkg-name
+        (if (listp theme2)
+            (setcar theme2 pkg-name)
+          (setq theme2 pkg-name))
+        (add-to-list 'dotspacemacs--additional-theme-packages theme2)))))
+(add-hook 'configuration-layer-pre-sync-hook
+          'spacemacs//add-theme-packages-to-additional-packages)
 
 (provide 'core-themes-support)

doc/DOCUMENTATION.org

@@ -62,6 +62,10 @@
  - [[#binding-keys][Binding keys]]
  - [[#gui-elements][GUI Elements]]
    - [[#color-themes][Color themes]]
+     - [[#default-theme][Default theme]]
+     - [[#choosing-themes][Choosing themes]]
+     - [[#browsing-themes][Browsing themes]]
+     - [[#notes][Notes]]
    - [[#font][Font]]
    - [[#gui-toggles][GUI Toggles]]
        - [[#global-line-numbers][Global line numbers]]
@@ -987,6 +991,7 @@ Spacemacs has a minimalistic and distraction free graphical UI:
   - [[Errors handling][custom fringe bitmaps]] and error feedbacks for [[https://github.com/flycheck/flycheck][Flycheck]]
 
 ** Color themes
+*** Default theme
 The official Spacemacs theme is [[https://github.com/nashamri/spacemacs-theme][spacemacs-dark]] and it is the default theme
 installed when you first started Spacemacs. There are two variants of the
 theme, a dark one and a light one. Some aspects of these themes can be customized
@@ -994,6 +999,7 @@ in the function =dotspacemacs/user-init= of your =~/.spacemacs=:
   - the comment background with the boolean =spacemacs-theme-comment-bg=
   - the height of org section titles with =spacemacs-theme-org-height=
 
+*** Choosing themes
 It is possible to define your default themes in your =~/.spacemacs= with the
 variable =dotspacemacs-themes=. For instance, to specify =spacemacs-light=,
 =leuven= and =zenburn=:
@@ -1002,26 +1008,44 @@ variable =dotspacemacs-themes=. For instance, to specify =spacemacs-light=,
 (setq-default dotspacemacs-themes '(spacemacs-light leuven zenburn))
 #+END_SRC
 
+=dotspacemacs-themes= entries accept the same properties as packages listed
+in layers package lists or in =dotspacemacs-addtional-packages=. So it is
+possible to fetch a package from a specific location. For example, you could
+fetch =zenburn= theme directly from the GitHub repository with the following
+declaration:
+
+#+BEGIN_SRC emacs-lisp
+(setq-default dotspacemacs-themes
+              '(spacemacs-light
+              leuven
+              (zenburn :location (recipe :fetcher github
+                                         :repo "bbatsov/zenburn-emacs"))
+              ))
+#+END_SRC
+
+You can cycle between the themes declared in =dotspacemacs-themes= with
+~SPC T n~ and select an installed theme with ~SPC T s~.
+
 | Key Binding | Description                                           |
 |-------------+-------------------------------------------------------|
 | ~SPC T n~   | switch to next theme listed in =dotspacemacs-themes=. |
 | ~SPC T s~   | select a theme using a =helm= buffer.                 |
 
-You can see samples of all included themes in this [[http://themegallery.robdor.com][theme gallery]] from [[http://www.twitter.com/robmerrell][Rob Merrell]].
+*** Browsing themes
+You can see samples of all themes included in the =themes-megapack= layer
+in this [[http://themegallery.robdor.com][theme gallery]] from [[http://www.twitter.com/robmerrell][Rob Merrell]].
 
-*Note*:
+*** Notes
-  - You don't need to explicitly list in a layer the theme packages you are
+- You don't need to explicitly list in a layer the theme packages you are
-    defining in =dotspacemacs-themes=, Spacemacs is smart enough to remove those
+  defining in =dotspacemacs-themes=, Spacemacs is smart enough to remove those
-    packages from the list of orphans.
+  packages from the list of orphans.
-  - Due to the inner working of themes in Emacs, switching theme during the same
+- Due to the inner working of themes in Emacs, switching theme during the same
-    session may have some weird side effects. Although these side effects should
+  session may have some weird side effects. Although these side effects should
-    be pretty rare.
+  be pretty rare.
-  - In the terminal version of Emacs, color themes will not render correctly as
+- In the terminal version of Emacs, color themes will not render correctly as
-    colors are rendered by the terminal and not by emacs. You will probably have
+  colors are rendered by the terminal and not by emacs. You will probably have
-    to change your terminal color palette. More explanations can be found on
+  to change your terminal color palette. More explanations can be found on
-    [[https://github.com/sellout/emacs-color-theme-solarized#important-note-for-terminal-users][emacs-color-theme-solarized webpage]].
+  [[https://github.com/sellout/emacs-color-theme-solarized#important-note-for-terminal-users][emacs-color-theme-solarized webpage]].
-
-*Hint*: If you are an =Org= user, [[https://github.com/fniessen/emacs-leuven-theme][leuven-theme]] is amazing ;-)
 
 ** Font
 The default font used by Spacemacs is [[https://github.com/adobe-fonts/source-code-pro][Source Code Pro]] by Adobe. It is