emacs: Add the html-escape module

1 files changed, 55 insertions, 0 deletions

diff --git a/.config/emacs/site-lisp/html-escape.el b/.config/emacs/site-lisp/html-escape.el
new file mode 100644
index 0000000..afdbb4d
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+++ b/.config/emacs/site-lisp/html-escape.el
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+;;; html-escape.el --- HTML escaping functions  -*- lexical-binding: t; -*-
+
+(defgroup html-escape nil
+  "Customization group for `html-escape'."
+  :group 'convenience)
+
+(defvar html-escape-table
+  (let ((table (make-hash-table :test #'eq)))
+    (puthash ?&  "&"  table)
+    (puthash ?<  "&lt;"   table)
+    (puthash ?>  "&gt;"   table)
+    (puthash ?\" "&quot;" table)
+    (puthash ?'  "&#39;"  table)
+    table)
+  "Hash table mapping character codes to their HTML entity equivalents.")
+
+;;;###autoload
+(defun html-escape ()
+  "HTML escape text in the current buffer.
+
+Perform HTML escaping on the text in the current buffer.  If the region
+is active then only escape the contents of the active region."
+  (declare (interactive-only t))
+  (interactive)
+  (if (use-region-p)
+      (html-escape-region (region-bounds))
+    (html-escape-region-1 (pos-bol) (pos-eol)))
+  (when (region-active-p)
+    (deactivate-mark)))
+
+(defun html-escape-region (bounds)
+  "HTML escape text in the current buffer within BOUNDS.
+
+BOUNDS takes the same form as the return value of `region-bounds'.  This
+function is prefered as it supports noncontiguous regions, but there also
+exists `html-escape-region-1' with a simpler bounds interface."
+  (dolist (x bounds) (html-escape-region-1 (car x) (cdr x))))
+
+(defun html-escape-region-1 (beg end)
+  "HTML escape text in the current buffer within BEG and END.
+
+This function is the same as the prefered `html-escape-region', but takes
+BEG and END parameters instead of a BOUNDS parameter.  For noncontiguous
+region support use `html-escape-region'."
+  (save-restriction
+    (narrow-to-region beg end)
+    (save-excursion
+      (goto-char (point-min))
+      (save-match-data
+        (while (re-search-forward "[&<>\"']" nil :noerror)
+          (let* ((char (char-after (match-beginning 0)))
+                 (replacement (gethash char html-escape-table)))
+            (replace-match replacement)))))))
+
+(provide 'html-escape)