transient-state: Improve handling of additional bindings

Add two new functions: `spacemacs/transient-state-register-add-bindings`
and `spacemacs/transient-state-register-remove-bindings` to prevent layer
authors and end users from dealing with the underlying variables' subtleties.

core/core-transient-state.el

@@ -27,6 +27,16 @@
 holds the key bindings."
   (intern (format "spacemacs/%S-transient-state/heads" name)))
 
+(defun spacemacs//transient-state-add-bindings-name (name)
+  "Return the name of the transient state add-bindings variable which
+may hold the additional key bindings. The variable may be unbound."
+  (intern (format "spacemacs-%s-transient-state-add-bindings" name)))
+
+(defun spacemacs//transient-state-remove-bindings-name (name)
+  "Return the name of the transient state remove-bindings variable which
+may hold the keys to be removed. The variable may be unbound."
+  (intern (format "spacemacs-%s-transient-state-remove-bindings" name)))
+
 (defun spacemacs//transient-state-adjust-bindings (bindings to-remove to-add)
   (append
    (cl-remove-if
@@ -47,6 +57,34 @@ holds the key bindings."
     (eval
      (hydra--format nil body docstring (symbol-value heads)))))
 
+(defun spacemacs/transient-state-register-add-bindings (name bindings)
+  "Register additional BINDINGS for the transient state NAME.
+
+BINDINGS should be a list of Hydra head definitions. See `defhydra'.
+
+Since a transient state initializes its Hydra right after
+the `dotspacemacs/user-config', this function will have no
+effect if called after that point."
+  (declare (indent defun))
+  (let ((var-name (spacemacs//transient-state-add-bindings-name name)))
+    (or (boundp var-name)
+        (set var-name '()))
+    (set var-name (append (symbol-value var-name) bindings))))
+
+(defun spacemacs/transient-state-register-remove-bindings (name keys)
+  "Register KEYS to be removed from the transient state NAME.
+
+KEYS should be a list of strings.
+
+Since a transient state initializes its Hydra right after
+the `dotspacemacs/user-config', this function will have no
+effect if called after that point."
+  (declare (indent defun))
+  (let ((var-name (spacemacs//transient-state-remove-bindings-name name)))
+    (or (boundp var-name)
+        (set var-name '()))
+    (set var-name (append (symbol-value var-name) keys))))
+
 (defmacro spacemacs|transient-state-format-hint (name var hint)
   "Format HINT and store the result in VAR for transient state NAME."
   (declare (indent 1))
@@ -126,10 +164,8 @@ used."
   (let* ((func (spacemacs//transient-state-func-name name))
          (props-var (spacemacs//transient-state-props-var-name name))
          (body-func (spacemacs//transient-state-body-func-name name))
-         (add-bindings
-          (intern (format "spacemacs-%s-transient-state-add-bindings" name)))
-         (remove-bindings
-          (intern (format "spacemacs-%s-transient-state-remove-bindings" name)))
+         (add-bindings (spacemacs//transient-state-add-bindings-name name))
+         (remove-bindings (spacemacs//transient-state-remove-bindings-name name))
          (bindings (spacemacs/mplist-get props :bindings))
          (doc (or (plist-get props :doc) "\n"))
          (title (plist-get props :title))

layers/+completion/helm/packages.el

@@ -46,12 +46,12 @@
     ;; add some functions to ahs transient states
     (setq spacemacs--symbol-highlight-transient-state-doc
           (concat spacemacs--symbol-highlight-transient-state-doc
-                  "  [_b_] search buffers [_/_] search proj [_f_] search files [_s_] swoop")
-     spacemacs-symbol-highlight-transient-state-add-bindings
-     '(("/" spacemacs/helm-project-smart-do-search-region-or-symbol :exit t)
-       ("b" spacemacs/helm-buffers-smart-do-search-region-or-symbol :exit t)
-       ("f" spacemacs/helm-files-smart-do-search-region-or-symbol :exit t)
-       ("s" spacemacs/helm-swoop-region-or-symbol :exit t)))))
+                  "  [_b_] search buffers [_/_] search proj [_f_] search files [_s_] swoop"))
+    (spacemacs/transient-state-register-add-bindings "symbol-highlight"
+      '(("/" spacemacs/helm-project-smart-do-search-region-or-symbol :exit t)
+        ("b" spacemacs/helm-buffers-smart-do-search-region-or-symbol :exit t)
+        ("f" spacemacs/helm-files-smart-do-search-region-or-symbol :exit t)
+        ("s" spacemacs/helm-swoop-region-or-symbol :exit t)))))
 
 (defun helm/post-init-bookmark ()
   (spacemacs/set-leader-keys "fb" 'helm-filtered-bookmarks))
@@ -643,6 +643,6 @@ Search for a search tool in the order provided by `dotspacemacs-search-tools'."
   (setq projectile-completion-system 'helm))
 
 (defun helm/post-init-persp-mode ()
-   (setq spacemacs-layouts-transient-state-add-bindings
-           '(("b" spacemacs/persp-helm-mini :exit t)
-             ("l" spacemacs/helm-perspectives :exit t))))
+  (spacemacs/transient-state-register-add-bindings "layouts"
+    '(("b" spacemacs/persp-helm-mini :exit t)
+      ("l" spacemacs/helm-perspectives :exit t))))

layers/+completion/ivy/packages.el

@@ -214,13 +214,13 @@
    'spacemacs/ivy-spacemacs-layouts
    '(("c" persp-kill-without-buffers "Close layout(s)")
      ("k" persp-kill  "Kill layout(s)")))
-  (setq spacemacs-layouts-transient-state-remove-bindings
-        '("C" "X"))
-  (setq spacemacs-layouts-transient-state-add-bindings
-        '(("b" spacemacs/ivy-spacemacs-layout-buffer :exit t)
-          ("l" spacemacs/ivy-spacemacs-layouts :exit t)
-          ("C" spacemacs/ivy-spacemacs-layout-close-other :exit t)
-          ("X" spacemacs/ivy-spacemacs-layout-kill-other :exit t))))
+  (spacemacs/transient-state-register-remove-bindings "layouts"
+    '("C" "X"))
+  (spacemacs/transient-state-register-add-bindings "layouts"
+    '(("b" spacemacs/ivy-spacemacs-layout-buffer :exit t)
+      ("l" spacemacs/ivy-spacemacs-layouts :exit t)
+      ("C" spacemacs/ivy-spacemacs-layout-close-other :exit t)
+      ("X" spacemacs/ivy-spacemacs-layout-kill-other :exit t))))
 
 (defun ivy/post-init-projectile ()
   (setq projectile-completion-system 'ivy)

layers/+spacemacs/spacemacs-navigation/packages.el

@@ -229,8 +229,8 @@
     :defer t
     :init
     (progn
-      (setq spacemacs-window-manipulation-transient-state-add-bindings
-            '(("g" spacemacs/toggle-golden-ratio)))
+      (spacemacs/transient-state-register-add-bindings "window-manipulation"
+        '(("g" spacemacs/toggle-golden-ratio)))
       (spacemacs|add-toggle golden-ratio
         :status golden-ratio-mode
         :on (golden-ratio-mode) (golden-ratio)