ins - the cmusic instrument command

The instrument command defines an instrument to be played by subsequent
note statements in a cmusic score.  It has the general form:

    ins T NAME;
	UG_STATEMENTS;
    end;

where:
    T             is the action time,
    NAME          is the name of the instrument being defined,
    UG_STATEMENTS is one or more unit generator statements which define the
		  instrument, and
    "end;"        signifies the end of the instrument definition.

Instruments are generally defined at the beginning of the score, at time 0.
The unit generators themselves are documented under:

    help cmusic/ugs

Example:
    
    ins 0 toot;				{define instrument toot}
	seg	b1 p5 f2 d p7 0 p8;	{amp envelope with shape=f2, amp=p5, 
					 att=p7, dec=p8}
	osc	b1 b1 p6 f1 d;		{carrier with waveshape=f1, freq=p6}
	out	b1;			{monophonic output}
    end;				{end of definition}

Note that it is illegal to use a p-field in a unit generator argument
expression, since p-fields are not constants (their value changes from
note to note).  For instance, the statement "osc  b1 p5 p6*.5 f1 d ;" is
illegal due to the use of p6 in an expression for the third argument.

It is possible to use bracketed index expressions for unit generator
arguments, provided the expressions have a constant value.  For example
the unit generator statement "osc b[1+v1] p[100-v2] p9 f[3+2] d ;" is
legal and is equivalent to "osc b5 p8 p9 f5 d ;" if v1=4 and v2=92.