add a type for CTCP-encoded strings, and NOTICEs for error cases

irc/strings.go

@@ -64,3 +64,12 @@ func NewText(str string) Text {
 func (text Text) String() string {
 	return string(text)
 }
+
+// CTCPText is text suitable escaped for CTCP.
+type CTCPText string
+
+var ctcpEscaper = strings.NewReplacer("\x00", "\x200", "\n", "\x20n", "\r", "\x20r")
+
+func NewCTCPText(str string) CTCPText {
+	return CTCPText(ctcpEscaper.Replace(str))
+}