Teach Geiser to detect installed Schemes

emacs/init.org

@@ -3408,6 +3408,14 @@ Tell emacs about file extensions which should activate scheme-mode:
 #+BEGIN_SRC emacs-lisp
   (use-package geiser
     :commands (run-geiser)
+    :config
+    (setq geiser-active-implementations
+          (cl-reduce (lambda (acc val)
+                       (if (executable-find (symbol-name val))
+                           (cons val acc)
+                         acc))
+                     '(guile racket chicken chez mit chibi gambit)
+                     :initial-value nil))
     :general
     (geiser-debug-mode-map "SPC" leader-map))
 #+END_SRC