Install yasnippet and vala-snippets packages

elpa/yasnippet-20160924.2001/snippets/emacs-lisp-mode/find-replace

@@ -0,0 +1,17 @@
+#name : find and replace on region
+#contributor : Xah Lee
+# --
+(defun replace-html-chars-region (start end)
+  "Replace “<” to “&lt;” and other chars in HTML.
+This works on the current region."
+  (interactive "r")
+  (save-restriction 
+    (narrow-to-region start end)
+    (goto-char (point-min))
+    (while (search-forward "&" nil t) (replace-match "&amp;" nil t))
+    (goto-char (point-min))
+    (while (search-forward "<" nil t) (replace-match "&lt;" nil t))
+    (goto-char (point-min))
+    (while (search-forward ">" nil t) (replace-match "&gt;" nil t))
+    )
+  )