Harmonic rhythm and proportional tempo helper functions

[AFrancoB]

One main feature of the work of Conlon Nancarrow is the use of proportional tempo based on the idea of harmonic rhythm described by Henry Cowell in the book New Musical Resources. It might be great to have a helper function that allows users to algorithmically design a tempo array that simultaneously produces transposition based in the proportional relationships formed by such tempos. We already have a function that might convert tempo into transposition values however it doesn´t perform the opposite operation and the transpositions are expressed in absolute values that will conflict with the values of the melody as it is presently designed. It also requires an octave / rhythm figure parameter to freely choose the register of its transposition/tempo.

(
~makeHarmRhythm= { | tempos, transp, proportions|
	var
	    propTempos= tempos*(proportions ? [1]),

		defaultProportions = if(proportions == nil,
			{tempos.cpsmidi},
			{propTempos.cpsmidi}
		),

		tempoToTransp= if(transp != nil,
			{transp},
			{defaultProportions},
		),

		resultingTempos = if(proportions == nil, {tempos}, {propTempos}),

		result = resultingTempos.size.collect({|i|
			(tempo: resultingTempos[i], transp: tempoToTransp[i])
		});

	//Post warnings on inconsistent data
	if(proportions != nil  && tempos.isArray, {"inconsistent tempos declared, tempos may be weird".warn});
	if( tempos.isArray && tempos.size == 1, {"inconsistent tempos declared, tempos may be weird".warn});

	result
}
)

// try me
~makeHarmRhythm.(tempos: [ 180, 240, 300, 360 ]);
// just arbitrary tempo, automatically generates transp with harmonic rhythm principle
~makeHarmRhythm.(tempos: 60, proportions: [3,4,5,6]);
// tempos generated proportionally, automatically generates transp with harmonic rhythm principle
~makeHarmRhythm.(tempos: 20, proportions: [3,4,5,6], transp: [12, 24, -12, -15]);
// tempos generated proportionally, transposition values generated arbitrarily
~makeHarmRhythm.(tempos: [ 180, 240, 300, 360 ], transp: [12, 24, -12, -15]);
// tempo and transposition generated arbitrarily

This function needs to work with the idea of transposition as function value proposed in issue #2 . It also requires an API that doesn´t 'convert' tempo to transposition but it is a new parameter that can be named and invoked in a new amazing and fantastic way.