each prior
Each prior
f':x
x f':y
x f':y
Each prior applies a two argument function(dyad) to each element, and the element prior to it.
If provided with a left argument, uses it as an initial value.
+':1 2 3 4 5 1 3 5 7 9 5+':1 2 3 4 5 6 3 5 7 9