* P2 must always be supplied.
* Commas and blanks in cyclic lists permitted.
* V_start blocks.
* Stop and Hold expressions, use of only begin time.
* v06 Functions, function pointers.
* Func_length().
* v07 Read_gen() Rel_time() and Func() and Rel_func().
* v08 Gen(), Hipn().
* v09 Numbers().
v10,v11 Tempo().
* v12 Stochastic functions.
* v13 Macros, 
v13 Start() and Stop().
* v14 Strings().
v15 M_start() and M_ter().
* v16 expr().
* v17 Read_motive().
v18 argc and argv[].
v19 Superfluous.
v20 argv to set begin and duration of a voice.
v21 P(), Ps() and Pp().
v22 Labels in compiled-in motives.
v23 Motive().
v24 Rest().
v25 Phrasing control.
v26 Redundant.
v27 Octave stick.
inherent variables
instance variables
p01 Superfluous.
p02 Self, Start() and Stop().
p03 Silent() and Hipn(0).
p04 New_voice() and sequencing.
p05 New_voice() on more than one voice.
p06 Wait_until().
p07,p08 Wait_for().
p09 Beg_time() Dur_time().
p10 Hold.
p11 Stop().
p12 Running voices from standard input.
p13 PiN variables.
v30 | measure signs
make a version of Wait_for() that only runs between Players.
P_to_I
make M_start and M_ter be pointers to functions?
