A scratch buffer and slime-selector integration

2 files changed, 86 insertions, 16 deletions

diff --git a/readme.org b/readme.org
index 41ec5d6..f4eca2e 100644
--- a/readme.org
+++ b/readme.org
@@ -151,13 +151,25 @@ active you could do something like this:
 (add-hook 'sps-mode-hook 'steal-slime-keys-for-sps!)
 #+END_SRC
 
+** Other amenities
+
+=slime-selector= is a great feature and =sps-mode= can optionally integrate
+with it. If you call =sps-add-slime-selector-methods=, two entries related to
+=sps-mode= will be added. One, invoked with =p=, will take you to the most
+recently visited buffer where =sps-mode= is active (excluding buffers which are
+already visible). The other, on =P=, will take you to a scratch buffer with
+=sps-mode= enabled, creating the buffer if necessary.
+
+Speaking of the scratch buffer, the =sps-scratch= command will take you
+straight there.
+
 ** Still do be done
 
     - Test against a wider array of code. Are there problems with quoting?
     - Better documentation.
-    - Add a REPL and/or a scratch buffer.
-    - See if more integration with SLIME is possible (e.g. the selector).
-    - Command(s) for compiling with the output going to a file.
+    - Look into adding a REPL.
+    - See if more integration with SLIME is possible.
+    - Command(s) for compiling to a file.
     - Similar support for [[http://weitz.de/cl-who/][CL-WHO]] and/or [[https://github.com/paddymul/css-lite][CSS-LITE]]?
     - Get to know ELPA and packaging.
     - Add support for Customize.
diff --git a/sps-mode.el b/sps-mode.el
index 27e1f54..ffd8cab 100644
--- a/sps-mode.el
+++ b/sps-mode.el
@@ -29,10 +29,9 @@
 
 (defvar sps-mode-map (make-sparse-keymap)
   "Keymap for sps-mode.
-This keymap is initialized empty. To repurpose the keys SLIME
-uses for its normal code evaluation and expansion commands, call
-`sps-shadow-slime-keybindings!`. Of course, you can alternatively
-define your own keybindings in the usual way.")
+This keymap is initialized empty. You can optionally use
+`sps-add-keys-with-prefix` to add bindings for all commands on
+two-key sequences behind a prefix of your choice.")
 
 (defvar sps-expansion-mode-map
   (let ((map (make-sparse-keymap)))
@@ -41,6 +40,9 @@ define your own keybindings in the usual way.")
     map)
   "Keymap for `sps-expansion-mode` buffers.")
 
+(defvar sps-scratch-mode-map (make-sparse-keymap)
+  "Keymap for the *sps-scratch* buffer.")
+
 (defvar sps-expansion-major-mode 'javascript-mode
   "The major mode to enable in expansion buffers.
 Note that a serious bug seems to be triggered when using js2-mode
@@ -192,6 +194,14 @@ If the region is active this is equivalent to invoking
       (sps-eval-region (region-beginning) (region-end))
     (sps-eval-defun)))
 
+(defun sps-send-expanded-code ()
+  "Send the expanded code to the browser.
+For use from `sps-expansion-mode` buffers."
+  (interactive)
+  (skewer-eval
+   (buffer-substring-no-properties (point-min) (point-max))
+   #'skewer-post-minibuffer))
+
 ;;;; Keybindings
 
 (defun sps-prefix-keys (prefix keys)
@@ -216,7 +226,58 @@ If the region is active this is equivalent to invoking
     (define-key map (sps-prefix-keys p "xb")    'sps-expand-buffer)
     (define-key map (sps-prefix-keys p "x SPC") 'sps-expand-dwim)))
 
-;;;; The minor mode
+;;;; Scratch buffer
+
+(defun sps-scratch-buffer ()
+  "Return the scratch buffer, creating it if necessary."
+  (let ((name "*sps-scratch*"))
+    (or (get-buffer name)
+        (with-current-buffer (get-buffer-create name)
+          (lisp-mode)
+          (slime-mode t)
+          (sps-mode 1)
+          (sps-scratch-mode 1)
+          (current-buffer)))))
+
+(defun sps-switch-to-scratch-buffer ()
+  "Jump to the *sps-scratch* buffer."
+  (set-buffer (sps-scratch-buffer))
+  (unless (eq (current-buffer) (window-buffer))
+    (pop-to-buffer (current-buffer) t)))
+
+(defun sps-scratch ()
+  "Jump to the *sps-scratch* buffer."
+  (interactive)
+  (sps-switch-to-scratch-buffer))
+
+;;;; A little extra SLIME integration
+
+(defun sps-mode-buffer-p (buffer)
+  "Return t if `sps-mode` is active in BUFFER."
+  (with-current-buffer buffer
+    (bound-and-true-p sps-mode)))
+
+(defun sps-recently-visited-sps-buffer ()
+  "Return the most recently visited `sps-mode` buffer.
+Only considers buffers that are not already visible."
+  (or (-first #'(lambda (b) (and (sps-mode-buffer-p b)
+                                 (null (get-buffer-window b 'visible))))
+              (buffer-list))
+      (error "Can't find unshown buffer in sps-mode")))
+
+(defun sps-add-slime-selector-methods ()
+  "Add methods to `slime-selector` for `sps-mode` buffers.
+Allows access to the most recently visited buffer with `sps-mode`
+active via \"p\" and to the *sps-scratch* buffer via \"P\"."
+  (interactive)
+  (def-slime-selector-method ?p
+    "most recently visited buffer using sps-mode."
+    (sps-recently-visited-sps-buffer))
+  (def-slime-selector-method ?P
+    "*sps-scratch* buffer."
+    (sps-scratch-buffer)))
+
+;;;; The minor modes
 
 ;;;###autoload
 (define-minor-mode sps-mode
@@ -224,14 +285,11 @@ If the region is active this is equivalent to invoking
   :lighter " sps"
   :keymap  sps-mode-map)
 
-;;;; Expansion minor mode
-
-(defun sps-send-expanded-code ()
-  "Send the expanded code to the browser."
-  (interactive)
-  (skewer-eval
-   (buffer-substring-no-properties (point-min) (point-max))
-   #'skewer-post-minibuffer))
+;;;###autoload
+(define-minor-mode sps-scratch-mode
+  "Mode for sps-mode scratch buffer."
+  :lighter nil
+  :keymap  sps-scratch-mode-map)
 
 (define-minor-mode sps-expansion-mode
   "Minor mode for displaying the code generated by Parenscript."