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<LI><A NAME="tex2html493"
  HREF="node15.html#SECTION001510000000000000000">Variables</A>
<UL>
<LI><A NAME="tex2html494"
  HREF="node15.html#SECTION001511000000000000000">Set [string]</A>
<LI><A NAME="tex2html495"
  HREF="node15.html#SECTION001512000000000000000">Mset [lines] MsetEnd/EndMset</A>
<LI><A NAME="tex2html496"
  HREF="node15.html#SECTION001513000000000000000">UnSet VariableName</A>
<LI><A NAME="tex2html497"
  HREF="node15.html#SECTION001514000000000000000">ShowVars</A>
<LI><A NAME="tex2html498"
  HREF="node15.html#SECTION001515000000000000000">Inc and Dec</A>
<LI><A NAME="tex2html499"
  HREF="node15.html#SECTION001516000000000000000">VExpand On or Off</A>
</UL>
<BR>
<LI><A NAME="tex2html500"
  HREF="node15.html#SECTION001520000000000000000">Predefined Variables</A>
<LI><A NAME="tex2html501"
  HREF="node15.html#SECTION001530000000000000000">Conditionals</A>
<LI><A NAME="tex2html502"
  HREF="node15.html#SECTION001540000000000000000">Goto</A>
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<H1><A NAME="SECTION001500000000000000000"></A>
<A NAME="sec-variables"></A>
<BR>
Variables, Conditionals and Jumps
</H1>

<P>
To make the processing of your music easier, <I><B>MMA</B></I> supports a very primitive set for variable manipulations along with some conditional testing and the oft-frowned-upon <I>goto</I> command.

<P>

<H1><A NAME="SECTION001510000000000000000">
Variables</A>
</H1>

<P>
<I><B>MMA</B></I> lets you set a variable, much like in other programming languages and to do some basic manipulations on them. Variables are most likely to be used for two reasons:

<P>

<UL>
<LI>For use in setting up conditional segments of your file,

<P>
</LI>
<LI>As a shortcut to entering complex chord sequences.

<P>
</LI>
</UL>

<P>
To begin, the following list shows the available commands to set and manipulate variables:

<P>

	<TABLE CELLSPACING=0 CELLPADDING=5" BGCOLOR="OldLace" BORDER=3><TR> <TD>
<BLOCKQUOTE><B>Set VariableName <I>String</I> 
<BR>
Mset VariableName ... MsetEnd 
<BR>
UnSet VariableName 
<BR>
ShowVars 
<BR>
Inc Variablename [value] 
<BR>
Dec Variablename [value] 
<BR>
Vexpand ON/Off   </B></BLOCKQUOTE>

	</TD></TR></TABLE> 

<P>
All variable names are case-insensitive. Any characters can be used in a variable name. The only exceptions are that a variable name cannot start with a ``$'' or a ``_'' (an underscore--this is reserved for internal variables, see below).

<P>
Variables are set and manipulated by using their names. Variables are expanded when their name is prefaced by a space followed by single ``$'' sign. For example:

<P>

	<TABLE CELLSPACING=0 CELLPADDING=5" BGCOLOR="OldLace" BORDER=3><TR> <TD>
<BLOCKQUOTE><B>Set Silly Am / Bm / 
<BR>
1 $Silly  </B></BLOCKQUOTE>

	</TD></TR></TABLE> 

<P>
The first line creates the variable ``Silly''; the second creates a bar of music with the chords ``Am / Bm /''.

<P>
Note that the ``$'' must be the first item on a line or follow a space character. For example, the following will NOT work:

<P>

	<TABLE CELLSPACING=0 CELLPADDING=5" BGCOLOR="OldLace" BORDER=3><TR> <TD>
<BLOCKQUOTE><B>Set Silly 4a;b;c;d; 
<BR>
1  Am  {$Silly}  </B></BLOCKQUOTE>

	</TD></TR></TABLE> 

<P>
However:

<P>

	<TABLE CELLSPACING=0 CELLPADDING=5" BGCOLOR="OldLace" BORDER=3><TR> <TD>
<BLOCKQUOTE><B>1 Am { $Silly}  </B></BLOCKQUOTE>

	</TD></TR></TABLE>  

<P>
will work fine.

<P>
Following are details on all the available variable commands:

<P>

<H2><A NAME="SECTION001511000000000000000">
Set [string]</A>
</H2> 

<P>
Set or create a variable. You can skip the <I>String</I> if you do want to assign an empty string to the variable. A valid example is:

<P>

	<TABLE CELLSPACING=0 CELLPADDING=5" BGCOLOR="OldLace" BORDER=3><TR> <TD>
<BLOCKQUOTE><B>Set PassCount 1 </B></BLOCKQUOTE>

	</TD></TR></TABLE> 

<P>

<H2><A NAME="SECTION001512000000000000000"></A>
	   
	<A NAME="sec-mset"></A>
<BR>
Mset [lines] MsetEnd/EndMset
</H2>

<P>
This command is quite similar to <I>Set</I>, but <I>Mset</I> expects multiple 	lines. An example:

<P>

	<TABLE CELLSPACING=0 CELLPADDING=5" BGCOLOR="OldLace" BORDER=3><TR> <TD>
<BLOCKQUOTE><B>MSet LongVar 
<BR>
1 Cm 
<BR>
2 Gm 
<BR>
3 G7 
<BR>
MsetEnd  </B></BLOCKQUOTE>

	</TD></TR></TABLE> 

<P>
It is quite possible to set a variable to hold an entire section of music (perhaps a chorus) and insert this via macro expansion at various places in your file.			   

<P>
Each <I>Mset</I> must be terminated by a <I>EndMset</I> or <I>MsetEnd</I> 	command (on its own separate line).

<P>

<H2><A NAME="SECTION001513000000000000000">
UnSet VariableName</A>
</H2> 	

<P>
Removes the variable. This can be useful if you have conditional tests which simply rely on a certain variable being ``defined''.

<P>

<H2><A NAME="SECTION001514000000000000000">
ShowVars</A>
</H2> 

<P>
Displays the names of the defined variables and their contents. Mainly used for debugging. The display will preface each variable name with a ``$''. Note that internal <I><B>MMA</B></I> variable are also displayed with this command.

<P>

<H2><A NAME="SECTION001515000000000000000">
Inc and Dec</A>
</H2>  

<P>
These commands increment or decrement a variable. If no argument is given, a value of 1 is used; otherwise, the value specified is used. The value can be an integer or a floating point number. 

<P>
A short example:

<P>

	<TABLE CELLSPACING=0 CELLPADDING=5" BGCOLOR="OldLace" BORDER=3><TR> <TD>
<BLOCKQUOTE><B>Set PassCount 1 
<BR>
Set Foobar 4 
<BR>
Showvars 
<BR>
Inc FooBar 4 
<BR>
Inc PassCount 
<BR>
ShowVars  </B></BLOCKQUOTE>

	</TD></TR></TABLE> 

<P>
This command is quite useful for creating conditional tests for proper handling of codas or groove changes in repeats.

<P>

<H2><A NAME="SECTION001516000000000000000">
VExpand On or Off</A>
</H2>

<P>
Normally variable expansion is enabled. These two options will turn expansion on or off. Why would you want to do this? Well, here's a simple example:

<P>

	<TABLE CELLSPACING=0 CELLPADDING=5" BGCOLOR="OldLace" BORDER=3><TR> <TD>
<BLOCKQUOTE><B>Set LeftC Am Em 
<BR>
Set RightC G / 
<BR>
VExpand Off 
<BR>
Set Full $LeftC $RightC 
<BR>
VExpand  On  </B></BLOCKQUOTE>

	</TD></TR></TABLE> 

<P>
In this case the actual contents of the variable ``Full'' is ``$LeftC $RightC''. If the <I>Off/On</I> option lines had not been used, the contents would be  ``Am Em G /''. You can easily verify this with the <I>ShowVars</I> 	option. 

<P>
When <I><B>MMA</B></I> processes a file it expands variables in a recursive manner. This means that, in the above example, the line:

<P>

	<TABLE CELLSPACING=0 CELLPADDING=5" BGCOLOR="OldLace" BORDER=3><TR> <TD>
<BLOCKQUOTE><B>1 $Full </B></BLOCKQUOTE>

	</TD></TR></TABLE> 

<P>
will be changed to:

<P>

	<TABLE CELLSPACING=0 CELLPADDING=5" BGCOLOR="OldLace" BORDER=3><TR> <TD>
<BLOCKQUOTE><B>1 Am Em G / </B></BLOCKQUOTE>

	</TD></TR></TABLE> 

<P>
However, if later in the file, you change the definition of one of the 	variables ...for example:

<P>

	<TABLE CELLSPACING=0 CELLPADDING=5" BGCOLOR="OldLace" BORDER=3><TR> <TD>
<BLOCKQUOTE><B>Set LeftC Am / </B></BLOCKQUOTE>

	</TD></TR></TABLE> 

<P>
the same line will now be ``1 Am / G /''.

<P>
Most of <I><B>MMA</B></I>'s internal commands <I>can</I> be redefined with variables. However, we really don't think you should use this feature. It's been left for two reasons: it might be useful, and, it's hard to disable.

<P>
However, not all commands can be redefined. The following is short list of things which will work (but, again, we're not suggesting you do this):

<P>

	<TABLE CELLSPACING=0 CELLPADDING=5" BGCOLOR="OldLace" BORDER=3><TR> <TD>
<BLOCKQUOTE><B>Set Rate Tempo 120 
<BR>		$Rate 
<BR>
Set  R Repeat 
<BR>		$R  </B></BLOCKQUOTE>

	</TD></TR></TABLE> 

<P>
But, the following will <I>not</I> work:

<P>

	<TABLE CELLSPACING=0 CELLPADDING=5" BGCOLOR="OldLace" BORDER=3><TR> <TD>
<BLOCKQUOTE><B>Set B Begin 
<BR>
Set  E End 
<BR>		$B Arpeggio Define 
<BR>		.... 
<BR>		$E  </B></BLOCKQUOTE>

	</TD></TR></TABLE> 

<P>
This fails since the Begin/End constructs are expanded before variable expansion. However:

<P>

	<TABLE CELLSPACING=0 CELLPADDING=5" BGCOLOR="OldLace" BORDER=3><TR> <TD>
<BLOCKQUOTE><B>Set A Define Arpeggio 
<BR>
Begin $a
		...
		End  </B></BLOCKQUOTE>

	</TD></TR></TABLE> 

<P>
is quite alright.

<P>
Even though you can use a variable to substitute for the <I>Repeat</I> or <I>If</I> directives, using one for <I>RepeatEnd/EndRepeat</I>, <I>RepeatEnding</I>. <I>Label</I> or <I>IfEnd/EndIf</I> will fail.

<P>
Variable expansion should usually not be a concern. In most normal files, <I><B>MMA</B></I> will expand variables as they are encountered. However, when reading the data in a <I>Repeat</I>, <I>If</I> or <I>Mset</I> section the expansion function is skipped--but, when the lines are processed, after being stored in an internal queue, variables are expanded. 

<P>

<H1><A NAME="SECTION001520000000000000000">
Predefined Variables</A>
</H1>

<P>
For your convenience <I><B>MMA</B></I> tracks a number of internal settings and saves their values in variables you can access just like you would a user defined variable. All of these ``internal'' variables are prefaced with a single underscore. For example, the current tempo is saved in the variable <I>_TEMPO</I>; this can be accessed in your script with the notation <I>$_TEMPO</I>.

<P>
<DL>
<DT><STRONG>_Groove</STRONG></DT>
<DD>Name of the currently selected groove. May be empty if no groove has been selected.

<P>
</DD>
<DT><STRONG>_LastGroove</STRONG></DT>
<DD>Name of the groove selected <I>before</I> the currently selected groove. 

<P>
</DD>
<DT><STRONG>_SeqSize</STRONG></DT>
<DD>Current <I>SeqSize</I> setting.

<P>
</DD>
<DT><STRONG>_Tempo</STRONG></DT>
<DD>Current <I>Tempo</I>. Note that if you have used the optional <I>bar count</I> in setting the tempo this will be the target tempo.

<P>
</DD>
<DT><STRONG>_Time</STRONG></DT>
<DD>The current <I>Time</I> (beats per bar) setting.

<P>
</DD>
<DT><STRONG>_Transpose</STRONG></DT>
<DD>Current <I>Transpose</I> setting.

<P>
</DD>
<DT><STRONG>_Volume</STRONG></DT>
<DD>Current global volume setting.

<P>
</DD>
<DT><STRONG>_LastVolume</STRONG></DT>
<DD>Previously set global volume setting.

<P>
</DD>
<DT><STRONG>_Debug</STRONG></DT>
<DD>Current debug settings.

<P>
</DD>
<DT><STRONG>_LastDebug</STRONG></DT>
<DD>Debug settings prior to last <I>Debug</I> command. This setting can be used to restore settings, ie:

<P>

	<TABLE CELLSPACING=0 CELLPADDING=5" BGCOLOR="OldLace" BORDER=3><TR> <TD>
<BLOCKQUOTE><B>Debug Warnings=off 
<BR>		   ... stuff generating annoying warnings
<BR>
Debug $_LastDebug  </B></BLOCKQUOTE>

	</TD></TR></TABLE> 

<P>
</DD>
</DL>

<P>

<H1><A NAME="SECTION001530000000000000000">
Conditionals</A>
</H1>   

<P>
The most important reason we created variables in <I><B>MMA</B></I> was to use them in conditionals. In <I><B>MMA</B></I> a conditional consists of a line starting with an <I>If</I> directive, a test, a series of lines to process (depending upon the result of the test), and a closing <I>EndIf</I> or <I>IfEnd</I><A NAME="tex2html58"
  HREF="#foot5094"><SUP>15.1</SUP></A>  directive. An optional <I>Else</I> statement may be included.

<P>
The first set of tests are unary (they take no arguments):

<P>
<DL>
<DT><STRONG>Def VariableName</STRONG></DT>
<DD>Returns true if the variable has been defined.

<P>
</DD>
<DT><STRONG>Ndef VariableName</STRONG></DT>
<DD>Returns true if the variable has not been defined.

<P>
</DD>
</DL>

<P>
In the above tests you must supply the name of a variable--don't make the mistake of including a ``$'' which will invoke expansion and result in something you were not expecting.

<P>
A simple example:

<P>

	<TABLE CELLSPACING=0 CELLPADDING=5" BGCOLOR="OldLace" BORDER=3><TR> <TD>
<BLOCKQUOTE><B>If Def InCoda 
<BR>		&nbsp;&nbsp;5 Cm 
<BR>		&nbsp;&nbsp;6 / 
<BR>
Endif </B></BLOCKQUOTE>

	</TD></TR></TABLE> 

<P>
The other tests are binary (they take two arguments):

<P>
<DL>
<DT><STRONG>LT Str1 Str2</STRONG></DT>
<DD>Returns true if <I>Str1</I> is less than <I>Str2</I>. (Please see the discussion below on how the tests are done.)

<P>
</DD>
<DT><STRONG>LE Str1 Str2</STRONG></DT>
<DD>Returns true if <I>str1</I> is less than or equal to <I>Str2</I>.

<P>
</DD>
<DT><STRONG>EQ Str1 Str2</STRONG></DT>
<DD>Returns true if <I>str1</I> is equal to <I>Str2</I>.

<P>
</DD>
<DT><STRONG>NE Str1 Str2</STRONG></DT>
<DD>Returns true if <I>str1</I> is not equal to <I>Str2</I>.

<P>
</DD>
<DT><STRONG>GT Str1 Str2</STRONG></DT>
<DD>Returns true if <I>str1</I> is greater than <I>Str2</I>.

<P>
</DD>
<DT><STRONG>GE Str1 Str2</STRONG></DT>
<DD>Returns true if <I>str1</I> is greater than or equal to <I>Str2</I>.

<P>
</DD>
</DL>

<P>
In the above tests you have several choices in specifying <I>Str1</I> and <I>Str2</I>. At some point, when <I><B>MMA</B></I> does the actual comparison, two strings or numeric values are expected. So, you really could do:

<P>

	<TABLE CELLSPACING=0 CELLPADDING=5" BGCOLOR="OldLace" BORDER=3><TR> <TD>
<BLOCKQUOTE><B>If EQ abc ABC </B></BLOCKQUOTE>

	</TD></TR></TABLE> 

<P>
and get a ``true'' result. The reason that ``abc'' equals ``ABC'' is that all the comparisons in <I><B>MMA</B></I> are case-insensitive. 

<P>
You can also compare a variable to a string:

<P>

	<TABLE CELLSPACING=0 CELLPADDING=5" BGCOLOR="OldLace" BORDER=3><TR> <TD>
<BLOCKQUOTE><B>If GT $foo abc </B></BLOCKQUOTE>

	</TD></TR></TABLE> 

<P>
will evaluate to ``true'' if the <I>contents</I> of the variable ``foo'' evaluates to something ``greater than'' ``abc''. But, there is a bit of a ``gotcha' here. If you have set ``foo'' to a two word string, then <I><B>MMA</B></I> will choke on the command. In the following example:

<P>

	<TABLE CELLSPACING=0 CELLPADDING=5" BGCOLOR="OldLace" BORDER=3><TR> <TD>
<BLOCKQUOTE><B>Set Foo A B 
<BR>
If GT $Foo abc  </B></BLOCKQUOTE>

	</TD></TR></TABLE> 

<P>
the comparison is passed the line:

<P>

	<TABLE CELLSPACING=0 CELLPADDING=5" BGCOLOR="OldLace" BORDER=3><TR> <TD>
<BLOCKQUOTE><B>If GT A B abc </B></BLOCKQUOTE>

	</TD></TR></TABLE> 

<P>
and <I><B>MMA</B></I> seeing three arguments generates an error. If you want the comparison done on a variable which might be more than one word, use the ``$$'' syntax. This delays the expansion of the variable until the <I>If</I> directive is entered. So:

<P>

	<TABLE CELLSPACING=0 CELLPADDING=5" BGCOLOR="OldLace" BORDER=3><TR> <TD>
<BLOCKQUOTE><B>If $$foo abc </B></BLOCKQUOTE>

	</TD></TR></TABLE>  

<P>
would generate a comparison between ``A B'' and ``ABC''.

<P>
Delayed expansion can be applied to either variable. It only works in an <I>If</I> directive.

<P>
Strings and numeric values can be confusing in comparisons. For example, if you have the strings ``22'' and ''3'' and compare them as strings, ``3'' is greater than ``22''; however, if you compare them as values then 3 is less than 22. 

<P>
The rule in <I><B>MMA</B></I> is quite simple: If either string in a comparison is a numeric value, both strings are converted to values. Otherwise they are compared as strings. <A NAME="tex2html59"
  HREF="#foot5123"><SUP>15.2</SUP></A>
<P>
This lets you do consistent comparisons in situations like:

<P>

	<TABLE CELLSPACING=0 CELLPADDING=5" BGCOLOR="OldLace" BORDER=3><TR> <TD>
<BLOCKQUOTE><B>Set Count 1 
<BR>
If LE $$Count 4 
<BR>		&nbsp;&nbsp;.... 
<BR>
IfEnd </B></BLOCKQUOTE>

	</TD></TR></TABLE> 

<P>
Note that in the above example we could have used ``$Count'', but you should probably always use the ``$$'' in tests.

<P>
Much like other programming languages, an optional <I>Else</I> condition may be used:

<P>

	<TABLE CELLSPACING=0 CELLPADDING=5" BGCOLOR="OldLace" BORDER=3><TR> <TD>
<BLOCKQUOTE><B>If Def Coda 
<BR>		&nbsp;&nbsp;Groove Rhumba1 
<BR>
Else 
<BR>		&nbsp;&nbsp;Groove Rhumba 
<BR>
Endif  </B></BLOCKQUOTE>

	</TD></TR></TABLE> 

<P>
The <I>Else</I> statement(s) are processed only if the test for the <I>If</I> test is false. 

<P>
Nesting of <I>If</I>s is permitted:

<P>

	<TABLE CELLSPACING=0 CELLPADDING=5" BGCOLOR="OldLace" BORDER=3><TR> <TD>
<BLOCKQUOTE><B>If ndef Foo 
<BR>		&nbsp;&nbsp;Print Foo has been defined. 
<BR>
Else 
<BR>		&nbsp;&nbsp;If def bar 
<BR>		&nbsp;&nbsp;&nbsp;&nbsp;Print bar has been defined. Cool. 
<BR>		&nbsp;&nbsp;Else 
<BR>		&nbsp;&nbsp;&nbsp;&nbsp;Print no bar...go thristy. 
<BR>		&nbsp;&nbsp;Endif 
<BR>
Endif  </B></BLOCKQUOTE>

	</TD></TR></TABLE> 

<P>
works just fine. We've used indentation in our examples to clearly show the nesting and conditions. We suggest you do the same.

<P>

<H1><A NAME="SECTION001540000000000000000">
Goto</A>
</H1> 

<P>
The <I>Goto</I> command redirects the execution order of you script to the point at which a <I>Label</I> has been defined. There are really two parts to this:

<P>

<OL>
<LI>A command defining a label, and,
</LI>
<LI>The <I>Goto</I> command.
</LI>
</OL>

<P>

<P>
A label is set with the <I>Label</I> directive:

<P>

	<TABLE CELLSPACING=0 CELLPADDING=5" BGCOLOR="OldLace" BORDER=3><TR> <TD>
<BLOCKQUOTE><B>Label Point1 </B></BLOCKQUOTE>

	</TD></TR></TABLE> 

<P>
The string defining the label can be any sequence of characters. Labels are case-insensitive. You can not set two points in your file to the same label.

<P>

<P>
To cause execution to jump to a labeled point:

<P>

	<TABLE CELLSPACING=0 CELLPADDING=5" BGCOLOR="OldLace" BORDER=3><TR> <TD>
<BLOCKQUOTE><B>Goto Point1 </B></BLOCKQUOTE>

	</TD></TR></TABLE> 

<P>
This causes an immediate jump. Any remaining lines in a repeat or conditional segment are discarded.

<P>
<I><B>MMA</B></I> does not check to see if you are jumping into a repeat or conditional section of code--but doing so will usually cause an error. Jumping out of these sections is usually safe.

<P>
For an example of how to use some simple labels to simulate a ``DS al Coda'' examine the file ``lullaby-of-Broadway'' in the sample songs directory.
<BR><HR><H4>Footnotes</H4>
<DL>
<DT><A NAME="foot5094">...IfEnd</A><A
 HREF="node15.html#tex2html58"><SUP>15.1</SUP></A></DT>
<DD>We probably suffer from mild dyslexia and can't remember if the command is IFEND or ENDIF, so both are permitted. Use whichever is more comfortable for you.

</DD>
<DT><A NAME="foot5123">... strings.</A><A
 HREF="node15.html#tex2html59"><SUP>15.2</SUP></A></DT>
<DD>An attempt is made to convert each string to a float. If conversion of both strings is successful, the comparison is made between two floats, otherwise two strings are used.

</DD>
</DL><HR>
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Bob
2004-12-02
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