On 11 August 2013 12:14, Steven D'Aprano <[email protected]> wrote: > On Sun, 11 Aug 2013 10:44:40 +0100, Joshua Landau wrote: > >> On 11 August 2013 10:09, Steven D'Aprano >> <[email protected]> wrote: >>> The reason some accented letters have single code point forms is to >>> support legacy charsets; the reason some only exist as combining >>> characters is due to the combinational explosion. Some languages allow >>> you to add up to five or six different accent on any of dozens of >>> different letters. If each combination needed its own unique code >>> point, there wouldn't be enough code points. For bonus points, if there >>> are five accents that can be placed in any combination of zero or more >>> on any of four characters, how many code points would be needed? >> >> 52? > > More than double that. > > Consider a single character. It can have 0 to 5 accents, in any > combination. Order doesn't matter, and there are no duplicates, so there > are: > > 0 accent: take 0 from 5 = 1 combination; > 1 accent: take 1 from 5 = 5 combinations; > 2 accents: take 2 from 5 = 5!/(2!*3!) = 10 combinations; > 3 accents: take 3 from 5 = 5!/(3!*2!) = 10 combinations; > 4 accents: take 4 from 5 = 5 combinations; > 5 accents: take 5 from 5 = 1 combination > > giving a total of 32 combinations for a single character. Since there are > four characters in this hypothetical language that take accents, that > gives a total of 4*32 = 128 distinct code points needed.
I didn't see "four characters", and I did (1 + 5 + 10) * 2 and came up with 52... Maybe I should get more sleep. -- http://mail.python.org/mailman/listinfo/python-list
