This is a fairly direct port of the C code to be found on John Walker's webpage titled Colour Rendering of Spectra. I've used named tuples to substitute for C structs, and the black body radiation example code has been taken into a separate source file. I've also eliminated the z CIE component from the exposed data structure, as this can always be derived from the x and y components:
The black body radiation test code produces the same output as Walker's C code, but I have not yet tested it further.