<chapter id="extending-solfege"><?dbhtml chunk.section.depth="0" ?>
<title>Extending GNU Solfege</title>
<sect1 id='extending-intro'>
<title>Introduction</title>
<para>GNU Solfege is written so that it can easily be extended, even if
you do not know any computer programming. The steps are:</para>
<itemizedlist>
<listitem><para>Create a lesson file.</para></listitem>
<listitem><para>Create a learning tree for your own lesson file. You do this only once.</para></listitem>
<listitem><para>Add the lesson file to the learning tree.</para></listitem>
</itemizedlist>

<para>Read <xref linkend='lesson-files'/> for details on creating lesson files.
The easiest way to get started is to take one of the existing lesson files, and
modify it. Select <guimenuitem>File locations</guimenuitem> on the
<guimenu>Help</guimenu> menu to find out where the included lesson files
are stored, and where you should save the additional files you create.
It is important to store the lesson files you create in the directory intended
for user created lesson files, and not in the applications directory. This
to avoid loosing files when you upgrade the program.</para>

<para>
The file paths is not written here in the user manual because the file path
depends on which operating system you run.</para>

<para>
You create a learning tree by opening the learning tree editor. Select
<guimenuitem>Learning tree</guimenuitem> from the <guimenu>Edit</guimenu> menu.
Then click the <guibutton>New</guibutton> button and enter a file name. Solfege
will suggest a directory to save learning trees, and unless you a good reason
to do so, I suggest you save the file there. You can find the location of this
directory in the File locations dialog.</para>

<para>Then you create a menu and a submenu with the learning tree editor, and
finally adds the lesson file to the selected submenu by clicking the
<guibutton>Add lesson</guibutton> button.</para>
</sect1>

<sect1 id='lesson-files'>
<title>Lesson files</title>
<para>In GNU Solfege, each exercise is created by a lesson file
interpreted by one of the exercise modules.</para>

<variablelist>
<title>Exercise modules</title>
<varlistentry>
<term><!-- translators: don't translate this string. -->
<literal>harmonicintervals</literal></term>
<listitem><para>Train harmonic intervals.</para></listitem>
</varlistentry>
<varlistentry>
<term><!-- translators: don't translate this string. -->
 <literal>melodicintervals</literal></term>
 <listitem><para>Train one or more melodic intervals.</para></listitem>
</varlistentry>
<varlistentry>
<term><!-- translators: don't translate this string. -->
<literal>singinterval</literal></term>
<listitem><para>This is an exercise where the
program display an interval and play the first tone. Then the user
should sing the interval, and then click a button to hear the correct
answer. There is no microphone support yet.</para></listitem>
</varlistentry>
<varlistentry>
<term><!-- translators: don't translate this string. -->
<literal>idbyname</literal></term>
<listitem><para>This is a very
generic exercise. In its most basic form, the program will play some sound,
and you have to select among several buttons that in some way represents
the music.</para></listitem>
</varlistentry>
<varlistentry>
<term><!-- translators: don't translate this string.-->
<literal>chordvoicing</literal></term>
<listitem><para>A two-step
exercise. First you should identify the chord. Then you should stack the
tones in the chord in the correct order.</para></listitem>
</varlistentry>
<varlistentry>
<term><!-- translators: don't translate this string.-->
<literal>compareintervals</literal></term>
<listitem><para>Solfege
plays two intervals, and you should say which one is largest.</para></listitem>
</varlistentry>
<varlistentry>
<term><!-- translators: don't translate this string.-->
<literal>rhythm</literal></term>
<listitem><para>A simple rhythm exercise. Solfege will randomly generate
rhythm patterns that the user should recreate by clicking on
buttons.</para></listitem>
</varlistentry>
<varlistentry><term><literal>dictation</literal></term><listitem><para></para></listitem></varlistentry>
<varlistentry><term><literal>harmonicprogressiondictation</literal></term><listitem><para></para></listitem></varlistentry>
<varlistentry><term><literal>idtone</literal></term><listitem><para></para></listitem></varlistentry>
<varlistentry><term><literal>identifybpm</literal></term><listitem><para></para></listitem></varlistentry>
<varlistentry><term><literal>twelvetone</literal></term><listitem><para></para></listitem></varlistentry>
<varlistentry><term><literal>singchord</literal></term><listitem><para></para></listitem></varlistentry>
</variablelist>

<sect2 id='File-encoding'>
<title>File encoding</title>
<indexterm><primary>File encoding</primary></indexterm>
<para>Solfege by default expects the content of lesson files to be in UTF-8
encoding.
Modern editors often let you
specify the encoding in the "Save As" dialog. One example is
<application>gedit</application>. Other programs, like
<application>vim</application> and <application>emacs</application> let you
specify the encoding inside the text file.</para>

<para>If this sounds complicated, you can safely ignore the whole
encoding issue if you restrict yourself to use only standard ascii
characters. That is only the letters a to z.
</para>

<para>If you create lesson files with a different encoding, you have to
declare the encoding in a special comment at the top of the file. This because
Solfege and the tools used to translate Solfege cannot guess the encoding
safely.
We follow the same conventions as the Python language. See
<ulink url="http://www.python.org/dev/peps/pep-0263/">PEP-0263</ulink>
for the details.</para>

<para>What you have to do is add a comment to one of the first two lines
of the lesson file, where part of the line matches <literal>coding=encoding</literal> or <literal>coding: encoding</literal>. Extra characters on the
line are ignored, so if you use the emacs or vim editors, you can conveniently
tell the editor about the file encoding. The following example sets
the charset to ISO 8859-1, a charset commonly used in many west-european
languages:
</para>

<programlisting># -*- coding: iso-8859-1 -*-</programlisting>
<para>Russians might want to use koi8-r:</para>
<programlisting># -*- coding: koi8-r -*-</programlisting>

<para>Same as above, but in a format that works with the <application>vim</application>:</para>
<programlisting># vim: set fileencoding= koi8-r :</programlisting>

<para>The program use the python libs to convert to unicode, so it
should understand almost any encoding you can think of. If you see some
characters are missing, for example when the name of questions are
displayed on buttons, then most likely you have done something wrong
with the encoding.</para>

</sect2>

<sect2 id='Useful-characters'>
<title>Useful unicode characters</title>
<para>Unicode has some characters that you might want to use to make labels
look more professionally. If your editor use unicode by default, you may
copy-and-paste the characters you need from here, if you are viewing this
documentation in a web browser. The number is a hexidecimal number.</para>
<variablelist>
 <varlistentry>
  <term>ø <literal>00F8 LATIN SMALL LETTER O WITH STROKE</literal></term>
  <listitem>
  <para>Half-diminished seventh chord.</para></listitem>
 </varlistentry>
 <varlistentry>
   <term>° <literal>00B0 DEGREE SIGN</literal></term>
   <listitem><para>Diminished seventh chord.</para></listitem>
 </varlistentry>
 <varlistentry>
   <term>△ <literal>25B3 WHITE UP-POINTING TRIANGLE</literal></term>
   <term>Δ <literal>0394 GREEK CAPITAL LETTER DELTA</literal></term>
   <listitem><para>Major seventh chord. We do not know
   which character to recommend. Solfege does not care, so you can use
   the symbol you like.
   </para></listitem>
 </varlistentry>
 <varlistentry>
   <term>♭ <literal>266D MUSIC FLAT SIGN</literal></term>
   <listitem><para>This sign can be used instead of the letter 'b' for a
   flat sign.</para></listitem>
 </varlistentry>
 <varlistentry>
   <term>♯ <literal>266F MUSIC SHARP SIGN</literal></term>
   <listitem><para>This can be used instead of the letter '#' for the
   sharp sign.</para></listitem>
 </varlistentry>
</variablelist>
</sect2>

<sect2 id='Comments'>
<title>Comments</title>
<indexterm><primary>Comments</primary></indexterm>
<para>Everything after # on a line is ignored. Example:</para>
<programlisting># This line is ignored. The next line is not.
question { bla bla }
</programlisting>
</sect2>

<sect2 id='Types'>
<title>Types</title>
<sect3 id='lf-types-strings'>
<title>Strings</title>
<indexterm><primary>Strings</primary></indexterm>
<para>Strings are quoted with the <literal>"</literal> character. Example:</para>
<programlisting>"this is a string"</programlisting>
<para>Use tripple quotes for strings that contain line breaks, or
if the string itself has to contain the <literal>"</literal> character:</para>

<programlisting>
description = """&lt;h1&gt;Long desription&lt;h1&gt; This lessonfile need
very much descriptions. Qoutes (") are ok here. bla bla bla"""</programlisting>

<para>NB: All strings have to be unicode strings. If you get error messages like this one:</para>
<programlisting>
In line 21 of input: does not recognise this string ';lt;' as a valid token.'
(line 20): question {
(line 21): question {
(line 22):   name = _("Ionia�)
</programlisting>
<para>then you must check the encoding of your file, and maybe you should
read <xref linkend='File-encoding'/>. You can change the encoding of a file using the <command>iconv</command> program:</para>
<programlisting>iconv -f YOUR_ENCODING -t utf8 your.file</programlisting>
</sect3>

<sect3 id='lf-type-tempo'>
<title>Tempo</title>
<para>The tempo of music is entered as <literal>bpm/beatlen</literal>. The
following example will set the tempo to 120 beats per minute, each beat being a
quarter note.</para>
<programlisting>tempo = 120/4</programlisting>
</sect3>
</sect2>

<sect2 id='Global-variables'>
<title>Global variables</title>
<indexterm><primary>Global variables</primary></indexterm>
<para>Global variables can save you a few key strokes.</para>
<programlisting>
s = "\score\relative c'{ %s }
question {
# instead of music = music("\score\relative c'{ c d e f g2 g2 }") 
music = music(s % "c d e f g2 g")
}
</programlisting>
</sect2>

<sect2 id='Lesson-file-contents'>
<title>Lesson file contents</title>
<para>A lesson file consist of one header block and zero or more
question blocks:</para>

<!-- translators: don't translate this string. -->
<programlisting>
header {
 ASSIGNMENT
 ASSIGNMENT
 ...
}
question {
 ASSIGNMENT
 ...
}
</programlisting>
</sect2>

<sect2 id='Header-block'>
<title>Header block</title>
<indexterm><primary>header block</primary></indexterm>
<para>The header block can be placed anywhere in the file, but by convention it should be the first block in the file.</para>

<variablelist id='lesson-header-vars'>
<title>Variables shared by many exercise modules</title>
<varlistentry>
 <term>
 <!-- translators: don't translate this string. -->
 <varname id='lf-module'>module</varname></term>
 <!-- translators: don't translate the string inside the <varname> element -->
 <listitem><para>Tell what execise module that will run the lesson file. This
 variable is requried for all lesson files. (The variable was added in
 Solfege 2.9.0 where it replaced the <varname>content</varname>
 variable.). Example:</para>
 <!-- translators: don't translate this string. -->
 <programlisting>module = idbyname</programlisting></listitem></varlistentry>

<varlistentry>
  <term><literal id='lf-lesson_id'>lesson_id</literal></term>
  <listitem>
  <indexterm><primary>lesson_id</primary></indexterm>
  <para>Each file need a unique identifier. The identifier can be any string
  you like, and if you don't add one, Solfege will add one for you. Solfege
  will also offer to create a new <literal>lesson_id</literal> if you have
  two files with identical <literal>lesson_id</literal>. Example:
  </para>
  <programlisting>lesson_id = "5b30c9ae-09f1-40b3-9333-4789638dc851"</programlisting>
  </listitem>
</varlistentry>

<varlistentry>
<term><!-- translators: don't translate this string. -->
<varname id='lf-version'>version</varname></term>
<listitem><para>
<indexterm><primary>version</primary></indexterm>
Tell the version of
solfege the lessonfile is known to work with. This variable is not
required, but it should be used because it can (but don't guarantee to)
help avoid trouble if the lesson file format changes in the future.
Example:</para>
<!-- translators: don't translate this string. -->
<programlisting>version = "3.0.7"</programlisting>
</listitem></varlistentry>

<varlistentry>
<term>
<!-- translators: don't translate this string. -->
<varname id='lf-title'>title</varname></term>
<listitem><para>
<indexterm><primary>title</primary></indexterm>
Short one-line description that will be used for
creating the menu entry for the exercise. You should add this to all lesson
files. Example:</para>
<!-- translators: Don't translate the word 'title'. -->
<programlisting>title = "Minor and major chords in root position"</programlisting>
</listitem></varlistentry>

<!--
<varlistentry>
<term>
 translators: don't translate this string.
<varname>description</varname></term>
<listitem><para>FIXME DEPRECATED. Optional, long description that can contain html tags. Use
this if you have to describe how the lesson file should be used.
This variable was used in Solfege 2.4. It is ignored in recent versions
of Solfege.</para>
</listitem></varlistentry>
-->
<varlistentry><term>
<!-- translators: don't translate this string. -->
<varname id="lf-lesson_heading">lesson_heading</varname></term>
<listitem><para>
<indexterm><primary>lesson_heading</primary></indexterm>
A short heading that will be displayed above the exercise. It
should say what the purpose of the exercise is. Some modules provide a
default value, others leave the string empty. Example:</para>
<programlisting>lesson_heading = _("Identify the chord")</programlisting>
</listitem></varlistentry>

<varlistentry><term>
<!-- translators: don't translate this string. -->
<varname id="lf-help">help</varname></term>
<listitem><para>
<indexterm><primary>help</primary></indexterm>
This variable say which help file from the user manual will be
displayed when the user presses F1.
Example:</para>
<programlisting>help = "idbyname-intonation"</programlisting>
<para>By default, Solfege will display the help file that has the same
name as the exercise module being used in the lesson file.</para>
</listitem></varlistentry>

<varlistentry><term>
<!-- translators: don't translate this string. -->
<varname id="lf-theory">theory</varname></term>
<listitem><para>
<indexterm><primary>theory</primary></indexterm>
This variable say which help file from the user manual will be
displayed when the user presses F3. Pressing F3 should display
music theory about the exercise. Don't include this variable if there
are no music theory written.
Example:</para>
<programlisting>theory = "scales/maj"</programlisting>
</listitem></varlistentry>

<varlistentry>
<term>
<!-- translators: don't translate this string. -->
<varname>random_transpose</varname></term>
<listitem>
<indexterm><primary>random_transpose</primary></indexterm>
<!-- translators: don't translate the strings inside <literal> elements -->
<para>In some exercises the program can transpose the music to
create variation. The default value is <literal>yes</literal>. (The
default value changed from <literal>no</literal> to
<literal>yes</literal> in Solfege 3.0.)</para>
<para>Used in modules: <literal>chord</literal>,
<literal>chordvoicing</literal>, <literal>harmonicprogressiondictation</literal>,
<literal>idbyname</literal>, <literal>singanswer</literal>,
<literal>singchord</literal></para>

    <variablelist>
    <title>Possible values</title>
        <varlistentry>
            <!-- translators: don't translate this string. -->
            <term>random_transpose = no</term>
            <listitem><para>No transposition will be done.</para></listitem>
        </varlistentry>

        <varlistentry>
            <!-- translators: don't translate this string. -->
            <term>random_transpose = yes</term>
            <listitem><para>The exercise will do random transposition. What
            kind of transposition depends on the exercise, but you get a
            ok result from this. This is the default value.</para></listitem>
        </varlistentry>

        <varlistentry>
            <!-- translators: don't translate the string 'random_transpose = accidentals'.
You can translate INTEGER1 and INTEGER2.-->
            <term>random_transpose = accidentals, INTEGER1, INTEGER2</term>
            <listitem>
            <para>
              Transpose the question by random and make sure the key signature
              of the question does not get more than a certain number of
              accidentals.  In this context, the number of accidentals can be
              described by an integer value. A negative value denote a number of
              flats (b), and a positive number denote a number o sharps (#).
              Zero mean no accidentals.  The integers INTEGER1 and INTEGER2
              defines a range of allowed number of accidentals.
            </para>
            <para>
              For this transposition mode to work properly, the music in
              the lessonfile has to be in the keys c major or a minor,
              or the question must have a <varname>key</varname>
              variable telling the key signature.
            </para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <!-- translators: don't translate the string 'random_transpose = key'.
You can translate INTEGER1 and INTEGER2. -->
            <term>random_transpose = key, INTEGER1, INTEGER2</term>
            <listitem>
            <para>
              Transpose the music INTEGER1 steps down or INTEGER2 steps up the
              circle of fifth. In this context up is more sharps and down is
              more flats. This is real transposition where both the key and the
              notes are transposed.
            </para></listitem>
        </varlistentry>

        <varlistentry>
            <!-- translators: don't translate the strings 'random_transpose = semitones'.
You can transpose INTEGER1 and INTEGER2.
            -->
            <term>random_transpose = semitones, INTEGER1, INTEGER2</term>
            <listitem>
            <para>
              Transpose the music at most INTEGER1 semitones down or INTEGER2
              semitones up. This is real transposition where both the key and
              the notes are transposed. You will easily end up with music in the
              keys with LOTS of accidentals.
            </para>
            </listitem>
        </varlistentry>

   </variablelist>
</listitem> </varlistentry>

<varlistentry>
    <term><literal>enable_right_click = no</literal></term>
    <listitem>
    <para>By default, Solfege will let the user right-click on buttons to hear
    the music they represent without guessing. Set this variable to
    <literal>no</literal> for lesson files where it does not make sense, for
    example in a <literal>idbyname</literal> lesson file where many questions
    have the same name.</para>
    <para>Modules: <literal>idbyname</literal>, <literal>chordvoicing</literal>
    and <literal>chord</literal>.</para>
    </listitem>
</varlistentry>

<varlistentry>
    <term>
    <!-- translators: don't translate this string. -->
    <varname
    id='lf-disable_unused_intervals'>disable_unused_intervals</varname>
    <!-- translators: don't translate this string. -->
    <literal>
    = no</literal></term>
    <listitem>
    <para>By default, Solfege will make the buttons insensitive for intervals
    that are not being asked. Set this variable to <literal>no</literal> if you
    want all buttons to be sensitive.
    </para>
    <para>Modules: <literal>harmonicinterval</literal> and
    <literal>melodicinterval</literal>.</para>
    </listitem>
</varlistentry>

<varlistentry>
    <term><literal id='lf-ask_for_intervals'>ask_for_intervals_0</literal></term>
    <listitem>
    <para>Select which intervals to ask for. 1 for minor second, 2 for major
    second, 3 or minor third etc. Use a negative number for descending
    intervals. To ask for more that one interval create the variables
    <literal>ask_for_intervals_1</literal>,
    <literal>ask_for_intervals_2</literal> etc. In the following example
    Solfege will ask for two intervals. The first will be either a minor second
    or a major second, both intervals going up. And the second interval will be
    either major second or minor third, both intervals going down.</para>

    <programlisting>ask_for_intervals_0 = [1, 2]
ask_for_intervals_1 = [-2, -3]
    </programlisting>
    <para>Modules: <literal>melodicinterval</literal> and
    <literal>singinterval</literal>.</para>
    </listitem>
</varlistentry>

<varlistentry>
    <term><varname id='lf-intervals'>intervals</varname></term>
    <listitem>
    <para>This variable tell which intervals should be asked for in exercises
    using the <literal>harmonicinterval</literal> module. 1 for minor second, 2 for major
    second, 3 or minor third etc. Example that will practise thirds:</para>
    <programlisting>intervals = [3, 4]</programlisting>
    <para>Modules: <literal>harmonicinterval</literal>.</para>
    </listitem>
</varlistentry>

<varlistentry>
    <term>
    <indexterm>
    <!-- translators: don't translate this string. -->
    <primary>test</primary></indexterm><varname id='lf-test'>test</varname></term>
    <listitem>
    <para>
        This variable defines the test for the exercise. In a test,
        Solfege will ask all the questions in the lesson file a number
        of times. 
        This variable is always used together with <varname>test_requirement</varname>.
        In the following example, each question will be asked
        3 times:
    </para>
    <programlisting>test = "3x"</programlisting>
    <para>Modules: <literal>harmonicinterval</literal>,
        <literal>idbyname</literal>, <literal>melodicinterval</literal>
        and <literal>singinterval</literal>.</para>
    </listitem>
</varlistentry>

<varlistentry>
    <term>
    <!-- translators: don't translate this string. -->
    <varname id='lf-test_requirement'>test_requirement</varname></term>
    <listitem>
    <para>
    <indexterm><primary>test_requirement</primary></indexterm>
    This variable defines how large percentage of the questions
    has to be answered correctly to pass the test. Example:
    </para>
    <programlisting>test_requirement = "90%"</programlisting>
    <para>Modules: <literal>harmonicinterval</literal>,
        <literal>idbyname</literal>, <literal>melodicinterval</literal>
        and <literal>singinterval</literal>.</para>
    </listitem>
</varlistentry>

<varlistentry>
    <term>
    <!-- translators: don't translate this string. -->
    <varname id='lf-have_repeat_arpeggio_button'>have_repeat_arpeggio_button</varname>
    <!-- translators: don't translate this string. -->
    <literal>= yes</literal></term>
    <listitem>
    <para>Set to <literal>yes</literal> if you want the exercise to have a
    "Repeat arpeggio" button.</para>
    <para>Modules: <literal>singanswer</literal>.</para>
    </listitem>
</varlistentry>

<varlistentry>
    <term>
    <!-- translators: don't translate this string. -->
    <varname id='lf-have_music_displayer'>have_music_displayer</varname>
    <!-- translators: don't translate this string. -->
    <literal>= yes</literal></term>
    <listitem>
    <para>Set to <literal>yes</literal> if you want the question to have a
    music displayer.</para>

    <para>In the idbyname module, setting this variable will add a
    music displayer where the program will display the answer when the
    user gives up or answers the question correctly. You might also want
    to read about <xref linkend='lf-at_question_start' endterm='lf-at_question_start'/>.</para>

    <para>In the <literal>singanswer</literal> module, setting this variable
    will add a music displayer where the music will be displayed when
    the question is displayed.</para>
    <para>Modules: <literal>idbyname</literal>,
       <literal>elembuilder</literal> and
       <literal>singanswer</literal>.</para>
    </listitem>
</varlistentry>

<varlistentry>
    <term>
    <!-- translators: don't translate this string. -->
    <varname id='lf-music_displayer_stafflines'>music_displayer_stafflines</varname>
    <!-- translators: don't translate this string. -->
    <literal>= INTEGER</literal></term>
    <listitem>
    <para>The number of empty staff lines to display when we have no
    music to display.</para>

    <para>Modules: <literal>idbyname</literal> and
       <literal>elembuilder</literal>.</para>
    </listitem>
</varlistentry>

<varlistentry>
    <term>
    <!-- translators: don't translate this string. -->
    <varname id='lf-at_question_start'>at_question_start</varname>
    <indexterm><primary>at_question_start</primary></indexterm>
    <!-- translators: don't translate this string. -->
    <literal></literal></term>
    <listitem>
    <para>This variable changes what happens when the user clicks
    <guibutton>New</guibutton>. By default, Solfege will play the music when
    the user clicks <guibutton>New</guibutton>, and only display the music
    when the question is answered correctly and the
    <varname>have_music_displayer</varname> variable is set to
    <literal>yes</literal>. Setting this variable will also set
    <varname>have_music_displayer</varname> to <literal>yes</literal>.
    </para>

    <variablelist>
    <varlistentry>
        <term><literal>at_question_start = show</literal></term>
        <listitem>
        <para>The exercise will get a <guibutton>Play music</guibutton> button.
        When the user clicks <guibutton>New</guibutton> the music will be
        displayed in the music displayer, but no music is played. Click
        <guibutton>Play music</guibutton> to hear the music.</para>
        </listitem>
    </varlistentry>
    <varlistentry>
        <term><literal>at_question_start = play</literal></term>
        <listitem>
        <para>The exercise will get a <guibutton>Display music</guibutton>
        button. When the user clicks <guibutton>New</guibutton> the music is
        played. Click <guibutton>Display music</guibutton> to see the
        music.</para>
        </listitem>
    </varlistentry>
    <varlistentry>
        <term><literal>at_question_start = show, play</literal></term>
        <listitem>
        <para>When the user clicks <guibutton>New</guibutton> the music is both
        played and displayed.</para>
        </listitem>
    </varlistentry>
    </variablelist>

    <para>Modules: <literal>idbyname</literal>, <literal>elembuilder</literal>
      and <literal>rhythmtapping2</literal>.</para>
    </listitem>
</varlistentry>

<varlistentry>
    <term><literal id='lf-vmusic'>vmusic</literal></term>
    <listitem>
    <para>This variable holds a representation of the question intended to be
    displayed. This can be necessary if the music is a .wav or .mp3 file. It
    will be used when the user clicks Show music or when the question is
    answered correctly (if we have a musicdisplayer). Added to
    <literal>idbyname</literal> in Solfege 2.5.1 and to
    <literal>elembuilder</literal> in 3.9.2.</para>
    <para>Modules: <literal>idbyname</literal> and <literal>elembuilder</literal>.</para>
    </listitem>
</varlistentry>
<varlistentry>
    <term><literal id='lf-rhythm_elements'>rhythm_elements</literal></term>
    <listitem>
    <para>A list of integers (1-34) telling what elementes we should use when
    creating questions. Example:</para>
    <programlisting>rhythm_elements = 0, 1, 2, 3, 4</programlisting>
    <xi:include
    xmlns:xi="http://www.w3.org/2001/XInclude" href="rhythmtable.xml"/>
    <para>Modules: <literal>rhythm</literal> and <literal>rhythmtapping2</literal></para>
    </listitem>
</varlistentry>

</variablelist>

<sect3 id='lf-obsolete-vars'>
<title>Variables that has been obsoleted</title>
<variablelist>
<varlistentry>
<term><literal>number_of_intervals = INTEGER</literal></term>
<listitem><para>Made obsolete in Solfege 3.1.5. Solfege will find this number automatically now, so this variable is ignored.</para></listitem>
</varlistentry>
</variablelist>
</sect3>
</sect2>

<sect2 id='Question-block'>
<title>Question block</title>
<variablelist>
<title>Variables you can define in the question block</title>

<varlistentry>
    <term><literal id='lf-name'>name</literal></term>
    <listitem>
    <para>Questions written for the
      <link linkend='idbyname-module'>idbyname</link> or 
      <link linkend='elembuilder-module'>elembuilder</link>
      exercise modules need a name. A name is optional for
      <link linkend='dictation-module'>dictation</link> module.</para>
    </listitem>
</varlistentry>

<varlistentry>
    <term><literal id='lf-music'>music</literal></term>
    <listitem>
    <para>
    For most lesson files the music representing the question is assigned to
    this variable. Note that there is a shortcut. Instead of:</para>
<programlisting>question {
  name = "Lisa gikk til skolen"
  music = music(...)"
}
</programlisting>
<para>you can write:</para>
<programlisting>question {
  name = "Lisa gikk til skolen"
  music(...)
}
</programlisting>
<para>Music objects are documented in <xref linkend='music-object'/>.</para>
    </listitem>
</varlistentry>

<varlistentry>
    <term><literal id='lf-tempo'>tempo</literal></term>
    <listitem>
    <para>Set the tempo for this questions music. The variable is defined
    "beats per minute" / "notelen per beat". Example:</para>
    <programlisting>tempo = 150 / 4</programlisting>
    <para>This variable can also be defined globally for the whole lesson file.
    Do do so you should put it in the beginning of the file, outside any
    question blocks.</para>
    <para>Modules: <literal>idbyname</literal>, <literal>chord</literal>,
        <literal>chordvoicing</literal> and
        <literal>rhythmtapping</literal>.</para>
    </listitem>
</varlistentry>

<varlistentry>
    <term><literal>instrument</literal></term>
    <listitem>
    <para>By default, Solfege will use the instrument specified on the
     <link linkend='preferences-window'>preferences window</link> when playing questions. This variable let you select a different instrument. Example:
    </para>
    <programlisting>instrument = "cello", 100</programlisting>
    <para>The instrument name has to be quoted. The integer is the volume,
    and it should be in the range 0-127. You can see a list of
    instrument names in <xref linkend='midi-instrument-names'/>. For lesson
    files where it makes sense, it is possible to specify three set of
    instruments. The following example will play bass for the lowest tone,
    piano in the middle and clarinet on the top tone:</para>
    <programlisting>instrument = "bass", 100, "acoustic grand", 100, "clarinet", 100</programlisting>
    <para>This variable can also be defined globally for the whole lesson file.
    Do do so you should put it in the beginning of the file, outside any
    question blocks.</para>
    <para>Modules: <literal>idbyname</literal>, <literal>chord</literal>,
        <literal>singanswer</literal> and <literal>chordvoicing</literal></para>
    <!-- ikke melodicinterval, singchord, compareintervals, ...-->
    </listitem>
</varlistentry>

<varlistentry>
    <term><literal>set</literal></term>
    <listitem>
    <para>The set variable is used by some exercise modules to select
    which question to play when the user right clicks on one of the
    answer buttons. This can be useful if the lesson file has many questions
    with the same name, and you want solfege to play the question that is
    most closely related to the question being asked. You can assign
    whatever value you want. A good suggestion is to use integers.</para>

    <para>In lesson files that does not use the <literal>set</literal> variable,
    solfege will play the first question it can find with
    the same name as the button the user right clicks on.</para>

    <para>If the lesson file uses the <literal>set</literal>, or more
    precisely, if the question being asked has the variable defined, the
    program will first try to find a question where the
    <literal>set</literal> variable matches the question being asked, and the
    name matches the button clicked. If no match is found,
    the program will select a question to play as if the
    <literal>set</literal> variable was not used at all.</para>

    <para>Modules: <literal>idbyname</literal> and
        <literal>chordvoicing</literal>.</para>
    </listitem>
</varlistentry>

</variablelist>
</sect2>

<sect2 id='music-object'>
<title><literal>music</literal> objects</title>
<para>Each question in your lesson files will define one or more
<literal>music</literal> objects.</para>

<variablelist>
<varlistentry>
    <term><emphasis role='bold' id='lfunc-music'>music</emphasis>(<emphasis>musiccode</emphasis>)</term>
    <listitem>
    <para>This is music entered completely following the <!--<xref
    linkend='music-format' endterm='music-format'/> --> music format FIXME spec. This means you
    have to enter complete code with a <literal>\staff</literal> command. Example:</para>
    <programlisting>variable = music("\staff\relative c' { c' d' }")</programlisting>
    </listitem>
</varlistentry>

<varlistentry>
    <term><emphasis role='bold' id='lfunc-music3'>music3</emphasis>(<emphasis>musiccode</emphasis>)</term>
    <listitem>
    <para>The music object can be used for music that has 3 or more staffs.
       It works the same way as <xref linkend='lfunc-music' endterm='lfunc-music'/>,
       but if "Use different instruments
       for chords and harmonic intervals" is checked in the preferences window,
       the 3 instruments you can select the same place will be used instead
       of the preferred MIDI instrument.
</para>
    </listitem>
</varlistentry>

<varlistentry>
    <term><emphasis role='bold' id='lfunc-chord'>chord</emphasis>(<emphasis>musiccode</emphasis>)</term>
    <listitem>
    <para>Enter the tones from the lowest to the highest tone, like this:</para>
    <programlisting>variable = chord("c' e' g'")</programlisting>
    </listitem>
</varlistentry>

<varlistentry>
    <term><emphasis role='bold' id='lfunc-satb'>satb</emphasis>(<emphasis>musiccode</emphasis>)</term>
    <listitem>
    <para>This type of music is used by the singchord exercises. It let you
    say which tones of a chord the different voices in a choir will sing.
    Take this, for example:</para>
    <programlisting>variable = satb("c''|e'|g|c")</programlisting>
    <para>The <literal>c''</literal> will be sung by the soprano, <literal>e'</literal> by the alto, <literal>g</literal> by the tenor and
    <literal>c</literal> by the bass. Please notice that when this music
    is played in arpeggio, the tones to be sung by the women, will be played
    one octave deeper, of the user is a male. And vice versa if the user
    is a female or a child.</para>
    </listitem>
</varlistentry>

<varlistentry>
    <term><emphasis role='bold' id='lfunc-voice'>voice</emphasis>(<emphasis>musiccode</emphasis>)</term>
    <listitem>
    <para>This musictype saves some key strokes if you want to enter a melody.</para>
    <programlisting>variable = voice("c'4 c' g' g' | a' a' g'2")</programlisting>
    <para>is the same as</para>
    <programlisting>variable = music("\staff{ c'4 c' g' g' | a' a' g'2")</programlisting>
    </listitem>
</varlistentry>

<varlistentry>
    <term><emphasis role='bold' id='lfunc-rvoice'>rvoice</emphasis>(<emphasis>musiccode</emphasis>)</term>
    <listitem>
    <para><varname>rvoice</varname> is similar to <varname>voice</varname>
    except that the music is in <literal>\relative</literal> mode, relative
    to the first tone. The following two statements produce the same music:</para>
    <programlisting>variable = rvoice("c'4 c g' g | a a g2")
\staff\relative c'{ c4 c g' g' | a a g2 }
    </programlisting>
    </listitem>
</varlistentry>

<varlistentry>
    <term><emphasis role='bold' id='lfunc-percussion'>percussion</emphasis>(<emphasis>percussioncode</emphasis>)</term>
    <listitem>
    <para>This music object provides a simple way to play
    rhythms with percussion instruments. Each tone represents a percussion
    instrument as defined in <xref linkend='percussion-instrument-names'/>.
    In the following example, the tone
    <emphasis>c</emphasis> is translated to the midi sound <emphasis>Side
    Stick</emphasis> and <emphasis>d</emphasis> to a <emphasis>Mute
    triangle</emphasis>.
    <programlisting>variable = rhythm("d4 d d d c8 c8 c4")</programlisting>
    </para>
    </listitem>
</varlistentry>

<varlistentry>
    <term><emphasis role='bold' id='lfunc-rhythm'>rhythm</emphasis>(<emphasis>musiccode</emphasis>)</term>
    <listitem>
    <para>This music object let you write questions that taps rhythms with the
    two instruments defined in the preferences window. The tone
    <literal>c</literal> will play the rhythm representing the question,
    and the tone <literal>d</literal> can be used if you want to write some
    sort of "count-in" before the question starts. Example:</para>
    <programlisting>rhythm("d4 d d d c8 c8 c4 c c8 c8")</programlisting>

    <para>You should only use two pitches, <literal>c</literal> and
    <literal>d</literal>. Other pitches will print a warning, but will still
    work in the current implementation. To play real percussion with many
    different instruments you should use the <xref linkend='lfunc-percussion'
    endterm='lfunc-percussion'/> music object.</para>

    </listitem>
</varlistentry>

<varlistentry>
    <term><emphasis role='bold' id='lfunc-midifile'>midifile</emphasis>(<emphasis>filename</emphasis>)</term>
    <listitem>
    <para>Play a midi file. The path given to the file
    is relative to the directory the lesson file is stored in. Example:</para>
    <programlisting>variable = midifile("share/example.mid")</programlisting>
    </listitem>
</varlistentry>

<varlistentry>
    <term><emphasis role='bold' id='lfunc-wavfile'>wavfile</emphasis>(<emphasis>filename</emphasis>)</term>
    <listitem>
    <para>Play a <literal>.wav</literal> file. The path given to the file
    is relative to the directory the lesson file is stored in. Example:</para>
    <programlisting>variable = wavfile("share/fifth-small-220.00.wav")</programlisting>
    </listitem>
</varlistentry>

<varlistentry>
    <term><emphasis role='bold' id='lfunc-mp3file'>mp3file</emphasis>(<emphasis>filename</emphasis>)</term>
    <listitem>
    <para>Play a MP3 file. Similar to <literal>wavfile</literal>.</para>
    </listitem>
</varlistentry>

<varlistentry>
    <term><emphasis role='bold' id='lfunc-oggfile'>oggfile</emphasis>(<emphasis>filename</emphasis>)</term>
    <listitem>
    <para>Play an Ogg Vorbis file. Similar to <literal>wavfile</literal>.</para>
    </listitem>
</varlistentry>

<varlistentry>
    <term><emphasis role='bold' id='lfunc-csound'>csound</emphasis>(<emphasis>orchestra</emphasis>, <emphasis>score</emphasis>)</term>
    <listitem>
    <para>Given a CSound orchestra and score, this music object will
    generate a WAV file and play it. Example:</para>
    <programlisting>csound(load("share/sinus.orc"), """
    f1 0 4096 10 1
    i1 0 1 220.0
    i1 + 1 329.04
    """)
    </programlisting>
    </listitem>
</varlistentry>

<varlistentry>
    <term><emphasis role='bold' id='lfunc-mma'>mma</emphasis>(<emphasis>mmacode</emphasis>)</term>
    <term><emphasis role='bold'>mma</emphasis>(<emphasis>groove, mmacode</emphasis>)</term>
    <listitem>
    <para>Create a music object that use <ulink url="http://www.mellowood.ca/mma/">MMA</ulink> to generate music that it will play. If you create the object
    with one argument, <emphasis>mmacode</emphasis> should be a string with
    complete MMA code. With two arguments, <literal>groove</literal> is
    a string with the name of the groove, and <literal>mmacode</literal> is
    comple MMA code, except it could be missing the initial
    "Groove" instruction. The groove from <literal>groove</literal>
    will be prepended the string.</para>
    </listitem>
</varlistentry>

<varlistentry>
    <term><emphasis role='bold' id='lfunc-cmdline'>cmdline</emphasis>(<emphasis>shell code</emphasis>)</term>
    <listitem>
    <para>Run an external program. Example:</para>
    <programlisting>cmdline("./bin/csound-play-harmonic-interval.sh 220.000000 320.100000")</programlisting>
    </listitem>
</varlistentry>

</variablelist>
</sect2>

<sect2 id='functions'>
<title>Functions</title>

<itemizedlist>
    <listitem>
    <para role="fdef"><literal>_(<replaceable>message</replaceable>)</literal></para>
    <para>
      Return the translation of <replaceable>message</replaceable> if it exist.
      Return the string unchanged if not.</para>
    <programlisting>title = _("Bla bla title")</programlisting>
    </listitem>

    <listitem><para role="fdef"><literal>include(<replaceable>filename</replaceable>)</literal></para>
    <para>Read the file <replaceable>filename</replaceable> into the lesson file
    and parse it as a part of the file.
    The filename is relative to the location of the lesson file.</para>
    <programlisting>include("singchord-1")</programlisting>
    <para>The lesson header variables will be taken from the including lesson
    file. Only if a variable is only defined in the included lesson file,
    and not in the including lesson file, then the value will be taken from the
    included file.</para>
    </listitem>

    <listitem><para role="fdef"><literal>load(<replaceable>filename</replaceable>)</literal></para>
    <para>Read the file <replaceable>filename</replaceable> from disk and return
    it as a string. The filename is relative to the location
    of the lesson file.</para>
    <programlisting>orc = load("share/sinus.orc")</programlisting>
    </listitem>
</itemizedlist>

<itemizedlist id="labelfunctions" xreflabel="label functions">
<title>Label functions</title>
<para>We call these functions <emphasis>label functions</emphasis> because
we use them to create the label for some questions in the program.
You should only use these functions where they are documented to work.</para>
 <listitem id="lfunc-pangomarkup" xreflabel="pangomarkup">
 <para role="fdef"><literal>pangomarkup</literal>(<replaceable>pangostring</replaceable>)</para>
 <para>Return a label that the program can put on a button. The label
 is created using GTK pangomarkup.
 <ulink url="http://www.google.com/search?q=pango+markup">
 Google for "pango markup"</ulink> to get the markup explained.
 Notice that you have to use triple qoutes around the string.</para>
 <programlisting><![CDATA[
pangomarkup("""<span size="xx-large">V</span>""")]]></programlisting>
 </listitem>


 <listitem id="lfunc-progressionlabel" xreflabel="progressionlabel">
 <para role="fdef"><literal>progressionlabel(<replaceable>str</replaceable>)</literal></para>
  <remark>This function has existed in Solfege for a while, but it has
  not been documented until now. Should we find a shorter function name?
  An alias can be added so that the old long function name still works.
  </remark>
 <para>Return a label. <replaceable>str</replaceable> is interpreted like
 this:</para>
 <itemizedlist>
 <listitem><para>Each letter outside of a parentheses is displayed with
 a large serif font.</para></listitem>
 <listitem><para>The text
 inside parentheses is displayed as a superscript: smaller letters above
 the baseline.</para></listitem>
 <listitem><para>If the text inside the parentheses is divided by a comma,
 the text before the comma is superscript and after the comma is subscript.
 </para></listitem>
 </itemizedlist>
 <programlisting>progressionlabel("I-IV-(6,4)V(5,3)-I")
progressionlabel("I-VI-V(6)-I")"
progressionlabel("C(maj7)")
 </programlisting>
    <informalfigure id="lfunc-progressionlabel-example1">
      <screenshot>
        <mediaobject>
          <imageobject>
            <imagedata fileref="figures/progressionlabel-example-1.png" format="PNG"/>
          </imageobject>
        </mediaobject>
      </screenshot>
    </informalfigure>
 </listitem>

 <listitem id="lfunc-rnc" xreflabel="rnc">
 <para role="fdef"><literal>rnc(<replaceable>str</replaceable>)</literal></para>
 <para>Display a sequence of roman numeral chords. The chords are separated
 by whitespace and an optional hyphen. The exact implementation of this is
 still open for discussion. The current developent version of Solfege will
 divide each chord in 3 parts and give them different font sizes, and also try
 to make the chord compact, so that it should not take too much space on
 screen.</para>
 <itemizedlist>
  <listitem><para>The first part of the chord is the roman numberal, including
  an optional <literal>b</literal> or <literal>♭</literal> 
  (unicode character <literal>U+266D MUSIC FLAT SIGN</literal>).
  </para></listitem>
  <listitem><para>The second part is the letters (if any) between the first
  and the third part.</para></listitem>
  <listitem><para>The third part is from the first digit and the rest of the
  chord.</para></listitem>
 </itemizedlist>
 <programlisting>rnc("Imaj7-IIm7-V9-Imaj7")</programlisting>
    <informalfigure id="fig-rnc">
      <screenshot>
        <mediaobject>
          <imageobject>
            <imagedata fileref="figures/rnc-example.png" format="PNG"/>
          </imageobject>
        </mediaobject>
      </screenshot>
    </informalfigure>
  <para>Spaces are not allowed in the chord name.</para>
  <para>New in version 3.11.0.</para>
 </listitem>

<listitem id="lfunc-chordname" xreflabel="chordname">
 <para role="fdef"><literal>chordname(<replaceable>str</replaceable>)</literal></para>
 <para>Display a sequence of chords. The chords are separated by whitespace.
 Each chord consist of up to four parts, and part two to four are optional:
 </para>
 <programlisting>[notename][txt1][:txt2][/bass]</programlisting>
 <para><literal>notename</literal> and <literal>bass</literal> music be
  a notename in the format understood by the music parser. You can read
  more about this in <xref linkend='mpd-module'/>. Example:</para>
 <programlisting>g:11b9 cm/g ges:Δ besm:7/f</programlisting>
    <informalfigure id="fig-chordname">
      <screenshot>
        <mediaobject>
          <imageobject>
            <imagedata fileref="figures/chordname-example.png" format="PNG"/>
          </imageobject>
        </mediaobject>
      </screenshot>
    </informalfigure>
  <para>New in version 3.11.1.</para>
</listitem>

</itemizedlist>
</sect2>

<sect2 id='lf-operators'>
<title>Operators</title>
<para>Operators can only be used on strings. <literal>+</literal> is used for
joining strings, and <literal>%</literal> is similar to what you find in
python, but it is very limited. It only know about <literal>%s</literal>. One
example:</para>

<programlisting>"\staff\relative c'{%s}" % "c d e"</programlisting>
<para>evaluates to</para>
<programlisting>\staff\relative c'{c d e}</programlisting>
</sect2>

</sect1>

<sect1 id='compareintervals-module'>
<title>The <literal>compareintervals</literal> module</title>
<para>Here is a minimal lesson file:</para>
<programlisting>
header {
    <xref linkend='lf-module' endterm='lf-countin_perc'/> = compareintervals
    <xref linkend='lf-title' endterm='lf-title'/> = "Compare intervals"
    <xref linkend='lf-lesson_id' endterm='lf-lesson_id'/> = "9f830e12-1f50-4fa9-8688-1e04469692fa"
}
</programlisting>
<para>This file will make an exercise that ask you to compare harmonic
intervals. And since you do not say which intervals, it will ask for all
intervals from a small second up to a major decim.</para>

<variablelist>
<varlistentry>
    <term><literal>first_interval_type</literal></term>
    <term><literal>second_interval_type</literal></term>
    <listitem>
    <para>Let you select if the intervals you are asked to compare should be a
    melodic or a harmonic interval. The default value is
    <literal>melodic</literal>. Possible values:
    <literal>harmonic</literal> and <literal>melodic</literal>.
    </para>
    <programlisting>
    first_interval_type = melodic
    second_interval_type = harmonic
    </programlisting>
    <para>Modules: <literal>compareintervals</literal>.</para>
    </listitem>
</varlistentry>

<varlistentry>
    <term><literal>first_interval</literal></term>
    <term><literal>last_interval</literal></term>
    <listitem>
    <para>Select which intervals to select from when creating the questions.
    This variable should be defined the same way as <xref
    linkend='lf-ask_for_intervals' endterm='lf-ask_for_intervals'/>. If these
    two variables are not defined, then the user will be able to select which
    intervals to practise from the Config page of the exercise.</para>
    <para>Modules: <literal>compareintervals</literal>.</para>
    </listitem>
</varlistentry>


</variablelist>
</sect1>

<sect1 id='dictation-module'>
<title>The <literal>dictation</literal> module</title>
<para>Example:</para>
<programlisting>
header {
  <xref linkend='lf-module' endterm='lf-module'/> = dictation
  <xref linkend='lf-lesson_id' endterm='lf-lesson_id'/> = "a265df62-e007-4a1b-9057-cd05397e88a2"
  <xref linkend='lf-title' endterm='lf-title'/> = _("Norwegian children songs")
  <xref linkend='lf-version' endterm='lf-version'/> = "2.1.10"
}

question {
 <xref linkend='lf-name' endterm='lf-name'/> = "Bæ, bæ, lille lam"
 <xref linkend='lf-tempo' endterm='lf-tempo'/> = 130/4
 <xref linkend='lf-breakpoints' endterm='lf-breakpoints'/> = 2/1, 4/1, 8/1, 10/1, 12/1, 14/1
 music = <xref linkend='lfunc-rvoice' endterm='lfunc-rvoice'/>("""
    \time 4/4
    c'2 g' | e4 e c2 | d4 d g, g | c1 |
    c2 g' | e4 e c2 | d4 d g, g | c1 |
    a'4 f f f | g2. e4 | f d d d | e2. c4 |
    a'2 f | g e4 e | f b, b b | c1 |
 """)
}
question {
 # this tempo definition overrides the global
 <xref linkend='lf-tempo' endterm='lf-tempo'/> = 160/4
 <xref linkend='lf-name' endterm='lf-name'/> = "Lisa gikk til skolen"
 <xref linkend='lf-breakpoints' endterm='lf-breakpoints'/> = 2/1, 4/1, 6/1
 music = <xref linkend='lfunc-rvoice' endterm='lfunc-rvoice'/>("""
   \time 4/4 
   c' d e f | g2 g2 | a4 a a a | g1 |
   f4 f f f | e2 e | d4 d d d | c1
 """)
}

question {
 name = "Det satt to katter på et bord..."
 tempo = 96/4
 music = rvoice("""
     \key g \major \time 2/4
     d'8 | [g g] [fis e] | [fis g] a4 | [d,16 d d d] [e8 fis] | g2 """)
}

</programlisting>
<para>By default, the dictation exercise will show the first column of music,
and then the user should write the rest. But if the first column is not good
enough, for example if there are only rests on the first beat, these two
variables can tell the program how much music to display:</para>

<variablelist>
<varlistentry>
    <term><literal id='lf-clue_end'>clue_end</literal></term>
    <listitem>
    <para>The following example will display the music on all staffs in
    the first quarter note:</para>
    <programlisting>clue_end=1/4</programlisting>
    </listitem>
</varlistentry>

<varlistentry>
    <term><literal id='lf-clue_music'>clue_music</literal></term>
    <listitem>
    <para>
    This is an alternative to <varname>clue_end</varname>. The music assigned
    to <varname>clue_music</varname> will be shown to the user when he should
    start the dictation. You should not use both <varname>clue_end</varname>
    and <literal>clue_music</literal> in the same question.</para>
    </listitem>
</varlistentry>

<varlistentry>
    <term><literal id='lf-breakpoints'>breakpoints</literal></term>
    <listitem>
    <para>Set breakpoints in the music, so you can hear the music in parts
    when doing the dictation.</para>
    </listitem>
</varlistentry>

</variablelist>
</sect1>

<sect1 id='elembuilder-module'>
<title>The <literal>elembuilder</literal> module</title>
<para>Here is a minimal lesson file:</para>
<programlisting>
element progI { label = "I" }
element progIV { label = "IV" }
element progV { label = "V" }

header {
    <xref linkend='lf-lesson_id' endterm='lf-lesson_id'/> = "3f3872c0-ef2e-4132-9fb1-97f75c7b28fd"
    <xref linkend='lf-module' endterm='lf-module'/> = elembuilder
    <xref linkend='lf-title' endterm='lf-title'/> = "progression test"
    <xref linkend='lf-header-elements' endterm='lf-header-elements'/> = auto
    # uncomment if you want a music displayer.
    # have_music_displayer = yes
}

question {
 <xref linkend='lf-music' endterm='lf-music'/> = rvoice("&lt;c' e g&gt; &lt;b d g&gt; &lt;c e g&gt;")
 <xref linkend='lf-header-elements' endterm='lf-question-elements'/> = progI, progV, progI
 <xref linkend='lf-name' endterm='lf-name'/> = "I-V-I"
}
question {
 <xref linkend='lf-music' endterm='lf-music'/> = rvoice("&lt;c' e g&gt; &lt;c f a&gt; &lt;c e g&gt;")
 <xref linkend='lf-header-elements' endterm='lf-question-elements'/> = progI, progIV, progI
 <xref linkend='lf-name' endterm='lf-name'/> = "I-IV-I"
}
</programlisting>

<sect2 id='elembuilder-element-block'>
<title>The element block</title>
<para>
This block defines the elements the user can put together to answer the
question. Each block is named by the string between <literal>element</literal>
and <literal>{</literal>. The block defines one variable,
<literal>label</literal> that is the label the button will get.</para>

<para><literal>label</literal> can either be a plain string or one
of the <xref linkend='labelfunctions'/>.
</para> </sect2>


<sect2 id='elembuilder-header-block'>
<title>The header block</title>
<variablelist>
<varlistentry>
    <term><literal id='lf-header-elements'>elements</literal></term>
    <listitem>
    <para>This variable defines which elements to display. Set this to <literal>auto</literal> to display all elements that are needed to answer the questions in the lesson file. You can display more elements that needed to make it more difficult for the user. An example:</para>
    <programlisting>elements = progI, progIV, progV, progIV, progV_6</programlisting>
    </listitem>
</varlistentry>
<varlistentry>
    <term><literal id='lf-header-music_displayer_stafflines'>music_displayer_stafflines</literal></term>
    <listitem>
    <para>Set this if you want the music displayer to show more than
    one empty staff line when the music displayer have no music to display.
    </para></listitem>
</varlistentry>
</variablelist>

<para>
See also <xref linkend='lf-at_question_start' endterm='lf-at_question_start'/>
and <xref linkend='lf-music_displayer_stafflines' endterm='lf-music_displayer_stafflines'/>.
</para>
</sect2>

<sect2 id='elembuilder-question-block'>
<title>The question block</title>
<variablelist>
<varlistentry>
    <term><literal id='lf-question-elements'>elements</literal></term>
    <listitem>
    <para>This variable defines which elements defines the question.
    It can be elements, as defined in the example above, or strings
    or labels defined by the <xref linkend="labelfunctions"/>.</para>
    </listitem>
</varlistentry>
<varlistentry>
    <term><literal id='lf-tonic'>tonic</literal></term>
    <listitem>
    <para>The exercise will have a "Play tonic" button if this variable is
    defined in a question in the lesson file. The variable should contain some
    music to play to the user so that he knows the tonic of the question.
    This can be useful in harmonic progressions that does not start on the
    tonic. This variable is optional. Example:</para>
    <programlisting>tonic = chord("c e g")</programlisting>
    </listitem>
</varlistentry>
<varlistentry>
    <term><literal>name</literal></term>
    <listitem>
    <para>The name is needed for storing statistics. A string or
    a label created by the <xref linkend="labelfunctions"/>. </para>
    </listitem>
</varlistentry>
</variablelist>
<para>See also <xref linkend='lf-vmusic' endterm='lf-vmusic'/>.</para>
</sect2>
</sect1>

<sect1 id='harmonicinterval-module'>
<title>The <literal>harmonicinterval</literal> module</title>
<para>User documentation is in <xref linkend='harmonicinterval'/>.</para>
<para>Here is a minimal lesson file:</para>
<!-- translators: don't translate this string. -->
<programlisting>
header {
  <xref linkend='lf-module' endterm='lf-module'/> = harmonicinterval
  <xref linkend='lf-lesson_id' endterm='lf-lesson_id'/> = "a400df62-e007-4a1b-9057-cd05397e88a2"
  <xref linkend='lf-version' endterm='lf-version'/> = "3.1.4"
  <xref linkend='lf-title' endterm='lf-title'/> = "Seconds"
  <xref linkend='lf-intervals' endterm='lf-intervals'/> = [1, 2]
  <xref linkend='lf-test' endterm='lf-test'/> = "3x"
  <xref linkend='lf-test_requirement' endterm='lf-test_requirement'/> = "90%"
}
</programlisting>
<para>Additional variables you can put in the header. Click on the link to
get an explanation:
<itemizedlist>
<listitem>
  <para>
  <xref linkend='lf-disable_unused_intervals' endterm='lf-disable_unused_intervals'/> 
  </para>
</listitem>
<listitem>
  <para><xref linkend='lf-lesson_heading' endterm='lf-lesson_heading'/></para>
</listitem>
</itemizedlist>
</para>
</sect1>

<sect1 id='idbyname-module'>
<title>The <literal>idbyname</literal> module</title>
<para>Here is a minimal lesson file:</para>
<programlisting>
header {
  <xref linkend='lf-module' endterm='lf-module'/> = idbyname
  <xref linkend='lf-lesson_id' endterm='lf-lesson_id'/> = "a400df62-e007-4a1b-9057-cd05397e88a2"
  <xref linkend='lf-version' endterm='lf-version'/> = "3.1.4"
  <xref linkend='lf-title' endterm='lf-title'/> = "Menuitem title"
}
question {
 name = "Major"
 music = chord("c' e' g'")
}
question {
 name = "Minor"
 music = chord("c' es' g'")
}
</programlisting>

<variablelist>
<title>Optional idbyname header variables</title>
<varlistentry>
    <term><literal>filldir = vertic</literal></term>
    <listitem>
    <indexterm><primary>filldir</primary></indexterm>
    <para>Tell the direction the buttons are filled. Default value is <literal>horiz</literal>.</para>
    <para>Modules: <literal>idbyname</literal>.</para>
    </listitem>
</varlistentry>

<varlistentry>
    <term><literal>fillnum</literal></term>
    <listitem>
     <indexterm><primary>fillnum</primary></indexterm>
     <para>Tell how many buttons there are in each row or column. 
     The default value is 1.</para>
     <para>Modules: <literal>idbyname</literal>.</para>
     </listitem>
</varlistentry>

<varlistentry>
    <term><literal id='lf-labelformat'>labelformat</literal><literal> = progression</literal></term>
    <listitem>
    <indexterm><primary>labelformat</primary></indexterm>
    <para>The default value is <literal>normal</literal>.
    Set to <literal>progression</literal> for lesson files where the name of the
    questions is a harmonic progression, written in a undocumented, but not
    difficult format. Check some existing lesson file to see how it works.
    <warning><para>Using this variable is deprecated. Do not use it for new
    lesson files.</para></warning>
    </para>
    <para>Modules: <literal>idbyname</literal></para>
    </listitem>
</varlistentry>

<varlistentry>
    <term>
    <!-- translators: don't translate this string. -->
    <varname id='lf-have_repeat_slowly_button'>have_repeat_slowly_button</varname>
    <!-- translators: don't translate this string. -->
    <literal>= yes</literal></term>
    <listitem>
    <indexterm><primary>have_repeat_slowly_button</primary></indexterm>
    <para>Set to <literal>yes</literal> if you want the exercise to have a "Repeat slowly" button.</para>
    <para>Modules: <literal>idbyname</literal>.</para>
    </listitem>
</varlistentry>

</variablelist>

<para>
See also <xref linkend='lf-at_question_start' endterm='lf-at_question_start'/>
and <xref linkend='lf-music_displayer_stafflines' endterm='lf-music_displayer_stafflines'/>.
</para>

<sect2>
<title>Question block</title>
<itemizedlist>
<title>Required question variables</title>
<listitem><para><xref linkend="lf-name" endterm="lf-name"/>. Can be a string
or a label created by the <xref linkend="labelfunctions"/>.</para></listitem>
<listitem><para><xref linkend="lf-music" endterm="lf-music"/></para></listitem>
</itemizedlist>

<variablelist>
<title>Optional question variables</title>
<varlistentry>
    <term><varname>vmusic</varname></term>
    <listitem>
    <indexterm><primary>vmusic</primary></indexterm>
    <para>See <xref linkend='lf-vmusic' endterm='lf-vmusic'/>.</para>
    </listitem>
</varlistentry>

<varlistentry>
    <term><varname>cuemusic</varname></term>
    <listitem>
    <indexterm><primary>cuemusic</primary></indexterm>
    <para>Will be displayed in the music displayer when the user clicks New.
    Ignored if <literal>at_question_start = play, show</literal> or
    <literal>at_question_start = show</literal>, because then the content of
    <varname>music</varname> or <varname>vmusic</varname> is displayed when the
    user clicks New. (Added in Solfege 2.5.1)</para>
    </listitem>
</varlistentry>
</variablelist>

</sect2>
</sect1>

<sect1 id='idproperty-module'>
<title>The <literal>idproperty</literal> module</title>
<para>
 The <literal>idproperty</literal> module let you create exercises where
 solfege will play some music and you have to identify different properties
 of the music.
</para>

<para>Below is a minimal lesson file. It will create an exercise that will play
a minor or major chord and the user answers with two buttons labeled "Minor"
and "Major" and two buttons representing the inversion. Notice that unused properties, toptone in this example, are hidden.</para>

<programlisting>
header {
    <xref linkend='lf-module' endterm='lf-module'/> = idproperty
    flavour = "chord"
    <xref linkend='lf-title' endterm='lf-title'/> = "Minor and major chords"
    <xref linkend='lf-lesson_id' endterm='lf-lesson_id'/> = "e263d40a-d8ff-4000-a7f2-c02ba087bf72"
}
question {
  name = "Major"
  music = chord("c' e' g'")
  inversion = 0
}
question {
  name = "Minor"
  music = chord("es' g' c''")
  inversion = 1
}
</programlisting>

<para><literal>flavour = "chord"</literal> will add the following definitions
to the lesson file header, unless if they are missing:</para>
<programlisting>
  new_button_label = _("_New chord")
  lesson_heading = _("Identify the chord")
  qprops = "name", "inversion", "toptone"
  qprop_labels = _("Name"), _("Inversion"), _("Toptone")
</programlisting>

<para><literal>new_button_label</literal> is the label to put on the
<guibutton>New</guibutton> button. The default value is
<literal>_("New")</literal>.</para>

<para><literal>lesson_heading</literal> will set the heading to be displayed
when you practise. The default value is an emptry string, that will hide the
heading.</para>

<para>The properties are defined by the <literal>props</literal> variable in
the lesson file header, and there should be a variable
<literal>prop_labels</literal> that defines the label to use.
<literal>props</literal> and <literal>prop_labels</literal> must be lists of
equal length.</para>


<para>The exercise will have a <guibutton>Repeat arpeggio</guibutton> button
if one or more of the questions can be played arpeggiated. Set the lesson file
header variable <literal>have_repeat_arpeggio_button</literal> to <literal>no</literal> to disable hide the button.</para>

<para>If the exercise have a <literal>inversion</literal> property, it will be
treated special. If assigned integer values, like in the example, the integer values will be replaced with strings. So <literal>0</literal> is replaced with "root position", <literal>1</literal> with "1. inversion" etc.</para>

</sect1>

<sect1 id='idtone-module'>
<title>The <literal>idtone</literal> module</title>
<para>Here is a minimal lesson file:</para>
<programlisting>
header {
    <xref linkend='lf-module' endterm='lf-module'/> = idtone
    <xref linkend='lf-title' endterm='lf-title'/> = "Id tone 3"
    <xref linkend='lf-lesson_id' endterm='lf-lesson_id'/> = "e263d70a-d8ff-4000-a7f2-c02ba087bf72"
    black_keys_weight =  0, 0,    0, 0, 0
    white_keys_weight = 1, 1, 1, 0, 0, 0, 0
}
</programlisting>
<para>The 'weight' of a tone tell how big chance is it that the program will
select this tone as the next to identify. Think of the weight of a tone as
the number of lottery tickets with the name of the tone.</para>

<para>The variable <varname>black_keys_weight</varname> set the weight of the
tones c#, d#, f#, g# and a#, and <varname>white_keys_weight</varname> will set
the weight of the tones c, d, e, f, g, a, b. In the example above, the tones c,
d and e get an equal weight of 1, the other tones 0. This mean that the only
tones that will be asked for are c, d and e, and that the three tones share the
same probability to be selected.</para>

</sect1>

<sect1 id='melodicinterval-module'>
<title>The <literal>melodicinterval</literal> module</title>
<para>User documentation is in <xref linkend='melodicinterval'/>.</para>
<para>Here is a minimal lesson file:</para>
<!-- translators: don't translate this string. -->
<programlisting>
header {
  <xref linkend='lf-module' endterm='lf-module'/> = melodicinterval
  <xref linkend='lf-lesson_id' endterm='lf-lesson_id'/> = "a400df62-e007-4a1b-9057-cd05397e88a2"
  <xref linkend='lf-version' endterm='lf-version'/> = "3.1.4"
  <xref linkend='lf-title' endterm='lf-title'/> = "Seconds and thirds"
  <xref linkend='lf-ask_for_intervals' endterm='lf-ask_for_intervals'/> = [1, 2, 3, 4, -1, -2, -3, -4]
  <xref linkend='lf-test' endterm='lf-test'/> = "3x"
  <xref linkend='lf-test_requirement' endterm='lf-test_requirement'/> = "90%"
}
</programlisting>
<para>Additional variables you can put in the header. Click on the link to
get an explanation:
<itemizedlist>
<listitem>
  <para>
  <xref linkend='lf-disable_unused_intervals' endterm='lf-disable_unused_intervals'/> 
  </para>
</listitem>
<listitem>
  <para><xref linkend='lf-lesson_heading' endterm='lf-lesson_heading'/></para>
</listitem>
</itemizedlist>
</para>

<para>Tests are only partially implemented for the
<literal>melodicinterval</literal> exercise module: tests where each question
is made by more than one interval does not work yet.</para>

</sect1>

<sect1 id='nameinterval-module'>
<title>The <literal>nameinterval</literal> module</title>
<para>Here is a minimal lesson file:</para>
<programlisting>
header {
    lesson_id = "5623c43e-f529-4376-a0c9-c7d533050360"
    module = nameinterval
    title = _("Fifths")
    intervals = p5, a5, d5
}
</programlisting>

<variablelist>
<varlistentry>
    <term><literal>intervals</literal></term>
    <listitem>
    <para>A list the the intervals to ask for. The intervals are written
    in a short form, a letter and a number, like <literal>d5</literal>
    or <literal>m7</literal>. The letters are telling the interval quality are
    'd' for diminished, 'a' for augmented, 'm' for minor, 'M' for major and
    'p' for perfect.
    </para>
    </listitem>
</varlistentry>

<varlistentry>
    <term><literal>tones</literal></term>
    <listitem>
    <para>This variable sets the range of tones that can be used when
    constructing the intervals. The note names as to be quoted. The
    default value is <literal>"b", "g''"</literal>. Example:
    </para>
    <programlisting>
tones = "c'", "f''"  # valid
tones = c', f''      # not valid</programlisting>
    </listitem>
</varlistentry>

<varlistentry>
    <term><literal>accidentals</literal></term>
    <listitem>
    <para>This variable defines how many accidentals the tones making
    the interval can have. The value 0 means no accidentals, 1 means that
    flats and sharps are allowed, and 2 means that double flats and double
    sharps are allowed. The default value is 1. Example:
    </para>
    <programlisting>accidentals = 2</programlisting>
    </listitem>
</varlistentry>

<varlistentry>
    <term><literal>clef</literal></term>
    <listitem>
    <para>Set which clef to use. The default value is <literal>violin</literal>.
    Possible values: <literal>violin</literal>, <literal>treble</literal>,
    <literal>subbass</literal>, <literal>bass</literal>, 
    <literal>baritone</literal>, <literal>varbaritone</literal>, 
    <literal>tenor</literal>, <literal>alto</literal>,
    <literal>mezzosoprano</literal> and <literal>french</literal>.
    Example:
    </para>
    <programlisting>clef = bass</programlisting>
    </listitem>
</varlistentry>

</variablelist>
</sect1>

<sect1 id='rhythm-module'>
<title>The <literal>rhythm</literal> module</title>
<para>Here is a minimal lesson file:</para>
<programlisting>
header {
  <xref linkend='lf-module' endterm='lf-module'/> = rhythm
  <xref linkend='lf-lesson_id' endterm='lf-lesson_id'/> = "7a4910be-de17-4ce3-9d15-78d48ccf945e"
  <xref linkend='lf-version' endterm='lf-version'/> = "3.1.4"
  <xref linkend='lf-title' endterm='lf-title'/> = "Easy rhythms"
  <xref linkend='lf-rhythm_elements' endterm='lf-rhythm_elements'/> = 1, 2, 3, 4
}
</programlisting>

<variablelist>
<varlistentry>
    <term><literal id='lf-visible_rhythm_elements'>visible_rhythm_elements</literal></term>
    <listitem>
    <para>Define this variable if you want more rhythm elements that the one to
    be asked for. This variable must include both the rhythm elements defined
    in <literal>rhythm_elements</literal> and the extra elements.
    Example:</para>
    <programlisting>rhythm_elements = 0, 1, 2, 3, 4, 5, 6</programlisting>
    </listitem>
</varlistentry>

<varlistentry>
    <term><literal id='lf-countin_perc'>countin_perc</literal></term>
    <listitem><para>
    An integer value between 35 and 81, representing the percussion instrument
    used to give you the beat before the question. The default value is 80.
    Example:
    </para>
    <programlisting>countin_perc = 35</programlisting>
    <programlisting>35 Acoustic Bass Drum 51 Ride Cymbal 1   67 High Agoga
36 Bass Drum          52 Chinece Cymbal  68 Agogo Low
37 Side Stick         53 Ride Bell       69 Cabasa
38 Acoustic Snare     54 Tambourine      70 Maracas
39 Hand Clap          55 Splash Cymbal   71 Short Whistle
40 Electric Snare     56 Cowbell         72 Long Whistle
41 Low Floor Tom      57 Crash cymbal 2  73 Short Guiro
42 Closed Hi Hat      58 Vibraslap       74 Long Guiro
43 High Floor Tom     59 Ride Cymbal 2   75 Claves
44 Pedal Hi Hat       60 Hi Bongo        76 Hi Wood Block
45 Low Tom            61 Low Bongo       77 Low Wood Block
46 Open HiHat         62 Mute Hi Conga   78 Mute Cuica
47 Low-Mid Tom        63 Open High Conga 79 Open Cuica
48 Hi-Mid Tom         64 Low Conga       80 Mute Triangle
49 Crash Cymbal 1     65 High Timbale    81 Open Triangle
50 High Tom           66 Low Timbale</programlisting>
        <para>Modules: <literal>rhythm</literal></para>
    </listitem>
</varlistentry>

<varlistentry>
    <term><literal id='lf_rhythm_perc'>rhythm_perc</literal></term>
    <listitem>
    <para>Same as <xref linkend='lf-countin_perc' endterm='lf-countin_perc'/>,
    but setting the instrument used to play the question. The default value is
    37.</para>
    <para>Modules: <literal>rhythm</literal></para>
    </listitem>
</varlistentry>

<varlistentry>
    <term><literal id='lf-count_in'>count_in</literal></term>
    <listitem>
    <para>The number of beats as count in. The default value is 2.</para>
    <para>Modules: <literal>rhythm</literal></para>
    </listitem>
</varlistentry>

<varlistentry>
    <term><literal id='lf-bpm'>bpm</literal></term>
    <listitem>
    <para>The tempo, in beats per minute. The default value is 60.</para>
    <para>Modules: <literal>rhythm</literal></para>
    </listitem>
</varlistentry>

<varlistentry>
    <term><literal id='lf-num_beats'>num_beats</literal></term>
    <listitem>
    <para>The number of elements the question is made of. The default
    value is 4.</para>
    <para>Modules: <literal>rhythm</literal></para>
    </listitem>
</varlistentry>

</variablelist>
</sect1>

<sect1 id='rhythmtapping-module'>
<title>The <literal>rhythmtapping</literal> module</title>
<para>Exercises using this module will play some music and then the user should
tap the rhythm. The program will then say if the users rhythm is similar enough
to the rhythm played by the computer.</para>

<para>Here is a minimal lesson file:</para>
<!-- translators: don't translate this string. -->
<programlisting>
header {
  <xref linkend='lf-module' endterm='lf-module'/> = rhythmtapping
  <xref linkend='lf-lesson_id' endterm='lf-lesson_id'/> = "82b718e8-f174-446f-8297-58ddd17dae03"
  <xref linkend='lf-version' endterm='lf-version'/> = "3.7.0"
  <xref linkend='lf-title' endterm='lf-title'/> = "Rhythm tapping test"
}
question {
 music = rhythm("c4 c8 c8")
}
question {
 music = music("\staff\relative c'{c4 d8 e f4}\addvoice\relative c'{c4 b8 c a4}")
 rhythm = rhythm("c4 c8 c c4")
}
</programlisting>

<para>The first question in the example is very simple and self explaining.
Solfege will play the rhythm defined in the <literal>music</literal> variable,
and the user should tap that rhythm.</para>

<para>The second question is a little more complicated. Here Solfege will play
the music defined in the <literal>music</literal> variable. And when the user
taps the rhythm, Solfege will compare the users rhythm with the rhythm defined
in the <literal>rhythm</literal> variable. The reason for using two variables
is that Solfege is not smart enought to figure out the rhythm if you enter
polyphonic music. It make noe difference if you set the
<literal>rhythm</literal> variable to be a <literal>rhythm</literal> music
object, or another single voice type like <literal>rvoice</literal>. This might
change in the future. You as a lesson file author must make sure the rhythms in
the two variables are in fact the same.</para>

</sect1>

<sect1 id='rhythmtapping2-module'>
<title>The <literal>rhythmtapping2</literal> module</title>
<para>Solfege will play a generated rhythm, and the user should tap the same
rhythm.</para>
<para>Here is a minimal lesson file:</para>
<!-- translators: don't translate this string. -->
<programlisting>
header {
  <xref linkend='lf-module' endterm='lf-module'/> = rhythmtapping2
  <xref linkend='lf-lesson_id' endterm='lf-lesson_id'/> = "7a4916be-de47-42e3-9d15-78d48ccf945e"
  <xref linkend='lf-version' endterm='lf-version'/> = "3.7.0"
  <xref linkend='lf-title' endterm='lf-title'/> = "Rhythm tapping test"
  <xref linkend='lf-rhythm_elements' endterm='lf-rhythm_elements'/> = 1, 2, 3, 4
}
</programlisting>
<para>See also <xref linkend='lf-at_question_start' endterm='lf-at_question_start'/>.</para>
</sect1>

<sect1 id='singanswer-module'>
<title>The <literal>singanswer</literal> module</title>
<para>Here is a minimal lesson file:</para>
<programlisting>
header {
  <xref linkend='lf-module' endterm='lf-module'/> = singanswer
  <xref linkend='lf-lesson_id' endterm='lf-lesson_id'/> = "a400df62-e007-4a1b-9057-cd05397e88a2"
  <xref linkend='lf-version' endterm='lf-version'/> = "3.1.4"
  <xref linkend='lf-title' endterm='lf-title'/> = "Sing the root of the chord"
}
question {
    question_text = "Sing the root"
    music = chord("c' e' g'")
    answer = chord("c'")
}
question {
    question_text = "Sing the root"
    music = chord("a' c'' e''")
    answer = chord("a'")
}
</programlisting>
<para>Additional variables you can put in the header. Click on the link to
get an explanation:
<itemizedlist>
<listitem>
  <para>
  <xref linkend='lf-have_repeat_arpeggio_button' endterm='lf-have_repeat_arpeggio_button'/>
  </para>
</listitem>
</itemizedlist>
</para>
</sect1>

<sect1 id='singchord-module'>
<title>The <literal>singchord</literal> module</title>
<para>Questions for this exercise need to have the <varname>key</varname> variable set if the key signature is anything else than ''c'' major (or ''a'' minor). Example:</para>
<programlisting>
header {
  <xref linkend='lf-module' endterm='lf-module'/> = singchord
  <xref linkend='lf-lesson_id' endterm='lf-lesson_id'/> = "a404df62-e037-6a1b-9027-cd05397e88a2"
  <xref linkend='lf-version' endterm='lf-version'/> = "3.1.4"
  <xref linkend='lf-title' endterm='lf-title'/> = "Simple chords"
}
question { music = satb("c''|e'|g|c") }
question { music = satb("a'|e'|c'|a") }
question { key="d \major" music = satb("a'|fis'|d'|d") }
question { key="f \minor" music = satb("as'|f'|c'|f") }
</programlisting>
<para>See also <xref linkend='singchord'/>.</para>
</sect1>

<sect1 id='singinterval-module'>
<title>The <literal>singinterval</literal> module</title>
<para>User documentation is in <xref linkend='singinterval'/>.</para>
<para>Here is a minimal lesson file:</para>
<programlisting>
header {
  <xref linkend='lf-module' endterm='lf-module'/> = singinterval
  <xref linkend='lf-lesson_id' endterm='lf-lesson_id'/> = "a400df62-e007-4a1b-9057-cd05397e88a2"
  <xref linkend='lf-version' endterm='lf-version'/> = "3.1.4"
  <xref linkend='lf-title' endterm='lf-title'/> = "Thirds"
  <xref linkend='lf-ask_for_intervals' endterm='lf-ask_for_intervals'/> = [3, 4]
  <xref linkend='lf-test' endterm='lf-test'/> = "3x"
  <xref linkend='lf-test_requirement' endterm='lf-test_requirement'/> = "90%"
}
</programlisting>
</sect1>

<sect1 id="mpd-module"><?dbhtml chunk.section.depth="0" ?>
<title>The <literal>mpd</literal> module</title>
<para>The module is not documented yet. The input format is similar to
the one used by GNU Lilypond, but only the simplest construct works.
</para>
<para>Quick note: Notenames understood by the program are c, d, e, f, g, a, b, with 'is', 'isis', 'es', or 'eses' added. For example 'fis', 'bes', 'gisis'.
</para>
</sect1>
<xi:include xmlns:xi="http://www.w3.org/2001/XInclude"
 href="midi-instrument-names.xml"/>

</chapter>

