Duck util-string.

doc/d-utils.md

@@ -371,3 +371,37 @@ A unifying module for compound data structures tagging.
 
 Creates a unique and collision free symbol to identify compound data
 structures based on lists and pairs.
+
+## util-string [module]
+
+    (import util-string)
+
+String manipulation functions which are used throughout other modules.
+
+### string-first+rest [procedure]
+
+    (string-first+rest str)
+
+* ```str``` - a string to split
+
+Returns a pair of strings where the ```car``` of the pair is the first
+token in the ```str``` given and ```cdr``` is a string with the
+remainder with leading whitespace removed.
+
+### string->qp [procedure]
+
+    (string->qp str)
+
+* ```str``` - arbitrary string
+
+Returns a new string with all non-ASCII characters encoded as
+quoted-printable sequences.
+
+### string-upcase [procedure]
+
+    (string-upcase str)
+
+* ```str``` - arbitrary string
+
+Returns the ```str``` with all characters converted to upper case
+using ```char-upcase```. Does not work with UTF-8.