SLY: Add sly-narrow-to-prompt.

.emacs.d/lisp/init-sly-narrow.el

@@ -0,0 +1,41 @@
+;; Requires `ambrevar/sly-end-of-prompt-p'.
+
+(defun ambrevar/sly-prompt-begin-position ()
+  (cond
+   ((and (get-text-property (point) 'sly-mrepl--prompt)
+         (not (get-text-property (1- (point)) 'sly-mrepl--prompt)))
+    (point))
+   ((or (get-text-property (point) 'sly-mrepl--prompt)
+        (ambrevar/sly-end-of-prompt-p))
+    (previous-single-char-property-change
+     (point) 'sly-mrepl--prompt))
+   (t (previous-single-char-property-change
+       (previous-single-char-property-change
+        (point) 'sly-mrepl--prompt)
+       'sly-mrepl--prompt))))
+
+(defun ambrevar/sly-prompt-end-position ()
+  (save-excursion
+    (goto-char (ambrevar/sly-prompt-begin-position))
+    (call-interactively #'sly-mrepl-next-prompt)
+    (point)))
+
+(defun ambrevar/sly-output-end-position ()
+  (if (get-text-property (point) 'sly-mrepl--prompt)
+      (next-single-char-property-change
+       (next-single-char-property-change
+        (point) 'sly-mrepl--prompt)
+       'sly-mrepl--prompt)
+    (next-single-char-property-change
+     (point) 'sly-mrepl--prompt)))
+
+(defun ambrevar/sly-narrow-to-prompt ()
+  "Narrow buffer to prompt at point."
+  (interactive)
+  (narrow-to-region
+   (ambrevar/sly-prompt-begin-position)
+   (ambrevar/sly-output-end-position)))
+
+(define-key sly-mrepl-mode-map (kbd "C-x n d") 'ambrevar/sly-narrow-to-prompt)
+
+(provive 'init-sly-narrow)

.emacs.d/lisp/init-sly.el

@@ -316,4 +316,6 @@ returns a string."
 (advice-add 'sly-mrepl-next-prompt :override #'ambrevar/sly-mrepl-next-prompt)
 (advice-add 'sly-mrepl-previous-prompt :override #'ambrevar/sly-mrepl-previous-prompt)
 
+(require 'init-sly-narrow)
+
 (provide 'init-sly)