Finish ducking.

doc/d-utils.md

@@ -609,3 +609,74 @@ Directory handling which didn't fit elsewhere.
 
 Makes sure given path exists and it is a directory. Throws an error
 if it exists and it is not a directory.
+
+## util-utf8 [module]
+
+    (import util-utf8)
+
+High-performance UTF-8 support.
+
+### utf8-char->string [procedure]
+
+    (utf8-char->string ch)
+
+Encodes given character as UTF-8.
+
+### make-utf8-string [procedure]
+
+    (make-utf8-string n
+                      (ch #\space))
+
+UTF-8 version of make-string.
+
+### string-append-utf8-char [procedure]
+
+    (string-append-utf8-char s
+                             ch)
+
+UTF-8 character append.
+
+### utf8-string->lists [procedure]
+
+    (utf8-string->lists str)
+
+Converts a UTF-8 string into two lists: list of UTF-8 characters
+of the string and a list of remaining bytes (as integers).
+
+### utf8-bytes->lists [procedure]
+
+    (utf8-bytes->lists chars)
+
+The same as above but accepts a list of bytes (as integers).
+
+### utf8-string-next-char [procedure]
+
+    (utf8-string-next-char str
+                           (si0 0))
+
+Returns the position right after the character at specified
+position.
+
+### utf8-string-length [procedure]
+
+    (utf8-string-length s)
+
+Calculates the length of given UTF-8 string.
+
+### utf8-string->list [procedure]
+
+    (utf8-string->list s)
+
+Converts utf8 string to list of unicode characters.
+
+### list->utf8-string [procedure]
+
+    (list->utf8-string lst)
+
+Converts list of unicode characters into utf8 string.
+
+### string-utf8? [procedure]
+
+    (string-utf8? s)
+
+Returns true, if given string contains UTF-8 characters.