From: Mark Wooding <mdw@distorted.org.uk>
Date: Wed, 1 Jul 2020 18:52:49 +0000 (+0100)
Subject: el/dot-emacs.el: Fix indentation of `loop'.
X-Git-Url: https://git.distorted.org.uk/~mdw/profile/commitdiff_plain/1be8ceca19b38d9ee61869667a0ee41055fffe15

el/dot-emacs.el: Fix indentation of `loop'.

This one has been annoying me for years.
---

diff --git a/el/dot-emacs.el b/el/dot-emacs.el
index 09da2d6..fc3c13f 100644
--- a/el/dot-emacs.el
+++ b/el/dot-emacs.el
@@ -4306,9 +4306,12 @@ that character only to be normal punctuation.")
 
 ;; Special indentation.
 
-(setq lisp-simple-loop-indentation 2
-      lisp-loop-keyword-indentation 6
-      lisp-loop-forms-indentation 6)
+(defvar mdw-lisp-loop-default-indent 2)
+
+(setq lisp-simple-loop-indentation 0
+      lisp-loop-keyword-indentation 0
+      lisp-loop-forms-indentation 2
+      lisp-lambda-list-keyword-parameter-alignment t)
 
 (defun mdw-indent-funcall (path state indent-point sexp-column normal-indent)
   "Indent `funcall' more usefully.
@@ -4327,6 +4330,58 @@ to `foo'."
 		       (current-column))))))))
 (put 'funcall 'common-lisp-indent-function 'mdw-indent-funcall)
 
+(defadvice common-lisp-loop-part-indentation
+    (around mdw-fix-loop-indentation (indent-point state) activate compile)
+  "Improve `loop' indentation.
+If the first subform is on the same line as the `loop' keyword, then
+align the other subforms beneath it.  Otherwise, indent them
+`mdw-lisp-loop-default-indent' columns in from the opening parenthesis."
+
+  (let* ((loop-indentation (save-excursion
+			     (goto-char (elt state 1))
+			     (current-column))))
+
+    ;; Don't really care about this.
+    (when (and (eq lisp-indent-backquote-substitution-mode 'corrected))
+      (save-excursion
+	(goto-char (elt state 1))
+	(cl-incf loop-indentation
+		 (cond ((eq (char-before) ?,) -1)
+		       ((and (eq (char-before) ?@)
+			     (progn (backward-char)
+				    (eq (char-before) ?,)))
+			-2)
+		       (t 0)))))
+
+    ;; If the first loop item is on the same line as the `loop' itself then
+    ;; use that as the baseline.  Otherwise advance by the default indent.
+    (goto-char (cadr state))
+    (forward-char 1)
+    (let ((baseline-indent
+	   (if (= (line-number-at-pos)
+		  (if (condition-case nil (progn (forward-sexp 2) t)
+			(scan-error nil))
+		      (progn (forward-sexp -1) (line-number-at-pos))
+		    -1))
+	       (current-column)
+	     (+ loop-indentation mdw-lisp-loop-default-indent))))
+
+      (goto-char indent-point)
+      (beginning-of-line)
+
+      (setq ad-return-value
+	    (list
+	     (cond ((not (lisp-extended-loop-p (elt state 1)))
+		    (+ baseline-indent lisp-simple-loop-indentation))
+		   ((looking-at "^\\s-*\\(:?\\sw+\\|;\\)")
+		    (+ baseline-indent lisp-loop-keyword-indentation))
+		   (t
+		    (+ baseline-indent lisp-loop-forms-indentation)))
+
+	     ;; Tell the caller that the next line needs recomputation, even
+	     ;; though it doesn't start a sexp.
+	     loop-indentation)))))
+
 ;; SLIME setup.
 
 (defvar mdw-friendly-name "[mdw]"