[gambit-list] SRFI 14 and data structures in gambit/lib/gambit/char/char#.scm

Bradley Lucier lucier at math.purdue.edu
Wed May 17 21:08:15 EDT 2023


On 5/17/23 5:33 PM, John Cowan wrote:
> 
> This is the design I like: a u32 vector such that each even element is 
> the starting code point of an interval and each odd element is the 
> ending code point + 1 of an interval, where the intervals are in order.  
> A binary search determines whether an element is in or out of the set.  
> Intersection is merge, and complement is "prepend #x00000 to the set and 
> remove the last element, unless the set already begins with #x00000, in 
> which case remove it and append #x200000".
> 
> See 
> https://github.com/scheme-requests-for-implementation/srfi-14/blob/master/contrib/unicode-2019/CharsetDefs.html > for how to make standard character set definitions that conform to 
Unicode rather than Java 1.0

Thanks, I'll look at.

Unicode has stretches of code-points that are invalid, doesn't it?  In 
which case complement would always be complement against the full valid 
Unicode set (which isn't a single contiguous range).

Brad



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