-
-// How to emulate Faust's seq, par, sum.
-// x(k) is assumed to yield the kth signal.
-
-xseq(1,x) = x(0);
-xseq(n,x) = xseq(n-1,x) : x(n-1);
-
-xpar(1,x) = x(0);
-xpar(n,x) = xpar(n-1,x) , x(n-1);
-
-xsum(1,x) = x(0);
-xsum(n,x) = xsum(n-1,x) + x(n-1);
-
-// These are all very similar. Abstracting
-// on the binary "accumulator" function, we
-// get the familiar fold(-left) function:
-
-fold(1,f,x) = x(0);
-fold(n,f,x) = f(fold(n-1,f,x),x(n-1));
-
-// Now seq, par, sum can be defined as:
-
-fseq(n) = fold(n,\(x,y).(x:y));
-fpar(n) = fold(n,\(x,y).(x,y));
-fsum(n) = fold(n,+);
-fprod(n) = fold(n,*);
-
-// Often it is more convenient to specify
-// parameters as a Faust tuple. We can match
-// against the (xs,x) pattern to decompose
-// these.
-
-vfold(f,(xs,x)) = f(vfold(f,xs),x);
-vfold(f,x) = x;
-
-// Tuple version of seq, par, sum:
-
-vseq = vfold(\(x,y).(x:y));
-vpar = vfold(\(x,y).(x,y));
-vsum = vfold(+);
-vprod = vfold(*);
-
-// Examples:
-
-import("music.lib");
-f0 = 440;
-a(0) = 1;
-a(1) = 0.5;
-a(2) = 0.3;
-h(i) = a(i)*osc((i+1)*f0);
-
-// sums
-//process = xsum(3,h);
-//process = fsum(3,h);
-//process = vsum((h(0),h(1),h(2)));
-
-reverse (x:y) = reverse(y):reverse(x);
-reverse(x) = x;
-
-// sequences from tuples (parallel -> serial)
-process = reverse(vseq((sin,cos,tan)));