[Discuss-gnuradio] Problems creating my own GRC blocks

[Iain Young, G7III]

Hi Guys,

I am trying to add my own block to GRC for Doppler correction. To be
honest, the code itself is a very simple python UDP Client that talks
to predict.

The code itself works fine, and talks to predict. So I decided to
create a block for GRC. This is the XML for the block:

<?xml version="1.0"?>
<block>
    <name>Predict Doppler</name>
    <key>get_doppler</key>
    <category>Misc</category>
    <import>from predict get_doppler</import>
    <callback></callback>
    <make>predict.get_doppler($predhost, $predport, $satellite)</make>
    <param>
        <name>Host</name>
        <value>localhost</value>
        <key>predhost</key>
        <type>string</type>
    </param>
    <param>
        <name>Port</name>
        <key>predport</key>
        <value>1210</value>
        <type>int</type>
    </param>
    <param>
        <name>Satellite</name>
        <value></value>
        <key>satellite</key>
        <type>string</type>
    </param>
    <source>
        <name>out</name>
        <type>float</type>
    </source>
</block>


However, I get the following when starting GRC:

Warning: Block validation failed:

/home/iain/.grc_gnuradio/predict.xml:2:0:ERROR:VALID:DTD_NOT_PCDATA: 
Element block was declared #PCDATA but contains non text nodes
/home/iain/.grc_gnuradio/predict.xml:4:0:ERROR:VALID:DTD_UNKNOWN_ELEM: 
No declaration for element key
/home/iain/.grc_gnuradio/predict.xml:5:0:ERROR:VALID:DTD_UNKNOWN_ELEM: 
No declaration for element category
/home/iain/.grc_gnuradio/predict.xml:6:0:ERROR:VALID:DTD_UNKNOWN_ELEM: 
No declaration for element import
/home/iain/.grc_gnuradio/predict.xml:7:0:ERROR:VALID:DTD_UNKNOWN_ELEM: 
No declaration for element make
/home/iain/.grc_gnuradio/predict.xml:8:0:ERROR:VALID:DTD_UNKNOWN_ELEM: 
No declaration for element param
/home/iain/.grc_gnuradio/predict.xml:10:0:ERROR:VALID:DTD_UNKNOWN_ELEM: 
No declaration for element value
/home/iain/.grc_gnuradio/predict.xml:11:0:ERROR:VALID:DTD_UNKNOWN_ELEM: 
No declaration for element key
/home/iain/.grc_gnuradio/predict.xml:12:0:ERROR:VALID:DTD_UNKNOWN_ELEM: 
No declaration for element type
/home/iain/.grc_gnuradio/predict.xml:14:0:ERROR:VALID:DTD_UNKNOWN_ELEM: 
No declaration for element param
/home/iain/.grc_gnuradio/predict.xml:16:0:ERROR:VALID:DTD_UNKNOWN_ELEM: 
No declaration for element key
/home/iain/.grc_gnuradio/predict.xml:17:0:ERROR:VALID:DTD_UNKNOWN_ELEM: 
No declaration for element value
/home/iain/.grc_gnuradio/predict.xml:18:0:ERROR:VALID:DTD_UNKNOWN_ELEM: 
No declaration for element type
/home/iain/.grc_gnuradio/predict.xml:20:0:ERROR:VALID:DTD_UNKNOWN_ELEM: 
No declaration for element param
/home/iain/.grc_gnuradio/predict.xml:22:0:ERROR:VALID:DTD_UNKNOWN_ELEM: 
No declaration for element value
/home/iain/.grc_gnuradio/predict.xml:23:0:ERROR:VALID:DTD_UNKNOWN_ELEM: 
No declaration for element key
/home/iain/.grc_gnuradio/predict.xml:24:0:ERROR:VALID:DTD_UNKNOWN_ELEM: 
No declaration for element type
/home/iain/.grc_gnuradio/predict.xml:26:0:ERROR:VALID:DTD_UNKNOWN_ELEM: 
No declaration for element source
/home/iain/.grc_gnuradio/predict.xml:28:0:ERROR:VALID:DTD_UNKNOWN_ELEM: 
No declaration for element type
        Ignoring: /home/iain/.grc_gnuradio/predict.xml


While googling, I only found one reference to this (back in 2009), and
that suggested that I needed a callback, even if it was empty, so I
added it, but to no avail.

I've compared my block to the others bundled with GRC, and can't see
anything that stands out. I've also updated to the latest git, but
still no luck (Previous was from sometime around Christmas/New Year)

Anyone have any ideas on what I've missed ?


Thanks in Advance & Best Regards

Iain