[plt-scheme] BitField

Paulo Jorge O. C. Matos wrote:

> Last week I was in need to control bits to implement RC4 private key 
> algorithm in 

> PLTScheme and I was not able to find something that would allow me to 
> check 

> bits and move them around, etc so I created a little module of 
> bitfield operations.

> Unfortunately I think it could be better but had no better idea. The 
> library is at:
> http://mega.ist.utl.pt/~pocm/bitfield.ss

I think you missed the bitwise operations. At first I overlooked them 
too, when
I implemented the md5 algorithm:

    http://www.scheme.dk/md5/md5.html

If you try it, then use time to see the difference between the builtin 
operations
and the userdefined. There is a world of difference.

Take also a look at Olin Shivers proposal for an integer bitwise-operation
library:

    http://srfi.schemers.org/srfi-33/srfi-33.txt

This looks very nice.

-- 
Jens Axel Søgaard