From: Mark Wooding <mdw@distorted.org.uk>
Date: Thu, 14 Feb 2019 13:18:21 +0000 (+0000)
Subject: dot/ercrc.el: Substitute problematic characters.
X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~mdw/git/profile/commitdiff_plain/8d190ffca441797f2297e1ea9cbef3a6eaa69400?ds=inline

dot/ercrc.el: Substitute problematic characters.

The problem is mostly emoji, arriving in Twitter announcements from
Servus: I think that mosh and putty (and maybe Emacs) have different
ideas about character width, and the terminal display ends up being a
total mess.
---

diff --git a/dot/ercrc.el b/dot/ercrc.el
index 3881cc1..a0bc5a6 100644
--- a/dot/ercrc.el
+++ b/dot/ercrc.el
@@ -5,14 +5,36 @@
 (setq erc-nick "mdw"
       erc-user-full-name "Mark Wooding")
 
-(if (not (memq 'truncate erc-modules))
-    (setq erc-modules (cons 'truncate erc-modules)))
+(dolist (module '(replace truncate))
+  (if (not (memq module erc-modules))
+      (setq erc-modules (cons module erc-modules))))
 
 (setq erc-fill-column 76
       erc-timestamp-right-column 68
       erc-fill-prefix "   "
       erc-max-buffer-size (* 60 3000))
 
+;; Filter out emoji, which cause severe display confusion.
+(defun mdw-replace-wide-characters (string)
+  (with-output-to-string
+    (let ((i 0)
+	  (state nil))
+      (while (< i (length string))
+	(let ((ch (aref string i)))
+	  (cond ((and (= (char-width ch) 1)
+		      (not (or (<= #x1f200 ch #x1ffff))))
+		 (when state (princ "*]") (setf state nil))
+		 (write-char ch))
+		(t
+		 (princ (if state "*" "[*"))
+		 (princ (format "#x%x" ch))
+		 (setf state t))))
+	(setq i (1+ i)))
+      (when state (princ "*]")))))
+
+(setq erc-replace-alist
+      '(("[[:nonascii:]+]" . mdw-replace-wide-characters)))
+
 (setq erc-track-exclude-types '("NICK" "JOIN" "PART"))
 
 (setq erc-auto-query 'buffer)