Expands the symbol pattern so that the number of symbols match the length pattern for the period of a zone with the quantisation of min-len. This is useful if you have two symbol patterns with different length values and want to align them to equal time base, where you can operate them, and then use compress-with-len to squeeze them back to normal.
(expand-with-len '(a b c d) '(1/16. 1/8) '1/1 '1/32)
--> (a a a b b b b c c c d d d d a a a b b b b c c c d d d d a a a b b b b)
(compress-with-len '(a a a b b b b c c c d d d d a a a b b b b c c c d d d d a a a b b b b)