diff --git a/texttools.tcl b/texttools.tcl
index cf9e71f..a1e7e33 100755
--- a/texttools.tcl
+++ b/texttools.tcl
@@ -1,9 +1,42 @@
 #!/usr/bin/env wish
 
-package require textutil
-
 set active_transform 0
 
+# Remove empty items at the beginning and the end of a list.
+proc ltrim {list} {
+    set first [lsearch -not -exact $list {}]
+    set last [lsearch -not -exact [lreverse $list] {}]
+    return [
+        if {$first == -1} {
+            list
+        } else {
+            lrange $list $first end-$last
+        }
+    ]
+}
+
+# Trim indentation in multiline quoted text.
+proc undent {msg {whitespaceChars " "}} {
+    set msgLines [split $msg "\n"]
+    set maxLength [string length $msg]
+
+    set regExp [subst -nocommands {([$whitespaceChars]*)[^$whitespaceChars]}]
+
+    set indent [
+        tcl::mathfunc::min {*}[
+            lmap x $msgLines {
+                if {[regexp $regExp $x match whitespace]} {
+                    string length $whitespace
+                } else {
+                    lindex $maxLength
+                }
+            }
+        ]
+    ]
+
+    join [ltrim [lmap x $msgLines {string range $x $indent end}]] "\n"
+}
+
 proc oneline {text} {
   return [regsub -all \n+ $text " "]
 }
@@ -20,7 +53,7 @@ proc wordcount {text} {
 }
 
 proc dedent {text} {
-  return [textutil::undent $text]
+  return [undent $text]
 }
 
 proc markdown_quote {text} {