histogram: rightmost bin edge is missing

[nilsbecker]

the array of bin ranges should have length n_bins + 1.

[nilsbecker]

more generally it would be better to have the option to specify non-uniform bin edges. e.g. an api like
histogram ?(bins=`N 10) ... where the bins keyword also accepts `Ranges of float array. unfortunately that would be backwards incompatible. or maybe, adding a new optional argument histogram ?(bins=10) ?ranges ... where ranges overrides bins if given?

[nilsbecker]

i checked the 'statistics' haskell library. i get now where the used interface is coming from: the upper bin edges are known in principle since the bins are always uniform. still i think this is too limited for a generally useful histogram function; non-uniform bins are important. since the output dimension would have to change, this would probably need to be an API breakage, or a new function histogram_nonuniform would be needed...