Improve indent logic in scheme-mode

Better indentation for property lists and functions starting with
'define'.

modules/lang/scheme/autoload.el

@@ -1,5 +1,50 @@
 ;;; lang/scheme/autoload.el -*- lexical-binding: t; -*-
 
+(defvar calculate-lisp-indent-last-sexp)
+
+;; Adapted from https://github.com/alezost/emacs-config/blob/master/utils/al-scheme.el#L76-L123
+;;;###autoload
+(defun +scheme-scheme-indent-function-a (indent-point state)
+  "Advice to replace `scheme-indent-function'.
+
+This function is the same as `scheme-indent-function' except it indents property
+lists properly and names starting with 'default'."
+  (let ((normal-indent (current-column)))
+    (goto-char (1+ (elt state 1)))
+    (parse-partial-sexp (point) calculate-lisp-indent-last-sexp 0 t)
+    (if (and (elt state 2)
+             ;; NOTE looking-at -> looking-at-p
+             (not (looking-at-p "\\sw\\|\\s_")))
+        (unless (> (save-excursion (forward-line 1) (point))
+                   calculate-lisp-indent-last-sexp)
+          (goto-char calculate-lisp-indent-last-sexp)
+          (beginning-of-line)
+          (parse-partial-sexp (point) calculate-lisp-indent-last-sexp 0 t))
+      (backward-prefix-chars)
+      (current-column)
+      (let* ((function (buffer-substring
+                        (point) (progn (forward-sexp 1) (point))))
+             (method (or (get (intern-soft function) 'scheme-indent-function)
+                         (get (intern-soft function) 'scheme-indent-hook))))
+        (cond ((or (eq method 'defun)
+                   (and (null method)
+                        (> (length function) 3)
+                        ;; NOTE string-match -> string-match-p
+                        ;; NOTE The original regexp is "\\`def" but it will mess
+                        ;;      indentation with such names as 'default-...'.
+                        (string-match-p "\\`define" function)))
+               (lisp-indent-defform state indent-point))
+              ;; NOTE Added this clause to handle alignment of keyword symbols
+              ((and (null method)
+                    (> (length function) 1)
+                    (string-match-p "\\`:" function))
+               (let ((lisp-body-indent 1))
+                 (lisp-indent-defform state indent-point)))
+              ((integerp method)
+               (lisp-indent-specform method state indent-point normal-indent))
+              (method
+               (funcall method state indent-point normal-indent)))))))
+
 ;;;###autoload
 (defun +scheme/open-repl (&optional arg)
   "Open the Scheme REPL."

modules/lang/scheme/config.el

@@ -1,7 +1,8 @@
 ;;; lang/scheme/config.el -*- lexical-binding: t; -*-
 
 (use-package! scheme
-  :hook (scheme-mode . rainbow-delimiters-mode))
+  :hook (scheme-mode . rainbow-delimiters-mode)
+  :config (advice-add #'scheme-indent-function :override #'+scheme-scheme-indent-function-a))
 
 
 (use-package! geiser