grc/misc_utils/gsm_message_printer.xml

<?xml version="1.0"?>
<block>
  <name>Message printer</name>
  <key>gsm_message_printer</key>
  <import>import grgsm</import>
  <import>import pmt</import>
  <make>grgsm.message_printer(pmt.intern($prepend_string))</make>

  <param>
    <name>Prepend String</name>
    <key>prepend_string</key>
    <value></value>
    <type>string</type>
    <hide>part</hide>
  </param>

  <sink>
    <name>msgs</name>
    <type>message</type>
  </sink>
</block>