Re: [Gnu-arch-users] [OT] Unicode meets Scheme strings draft

[Tom Lord]

    > From: David Allouche <address@hidden>

    > 
    > On Wed, Jan 21, 2004 at 09:12:26PM -0800, Tom Lord wrote:
    > >   /=== Pika Design:

    > >    Pika is of the "approximately 2^21 characters" variety.

    > >    Specifically, the Pika CHAR? type will in effect be a _superset_ of
    > >    the set of Unicode codepoints.   Each 21-bit codepoint will
    > >    correspond to a Pika character.   For each such character, there 
    > >    will be (2^4-1) (15) additional related characters representing the
    > >    basic code point modified by a combination of any of four
    > >    "buckybits".

    > Each Pika char is 21 bits long, 4 bits are used for bucky bits, that
    > leaves 17 bits for the unicode characters.

Sorry -- the draft is unclear here.   

Each Pika character is 25 bits.  21 bits for a Unicode codepoint, then
4 more for buckybits.

    > Also, the set of bucky bits seems a bit limited to me.

    > In TeXmacs, we represent keypress sequences as character strings, like
    > "C-x C-c", "M-<", or "S-return". I see no compelling reason why
    > "control" could not be a bucky bit. Though there not (yet) any support
    > for the "super" modifier, that's one modifier someone used once, so
    > someone may want to use it again (that could be a use for Menu key of
    > international keyboards).

    > Why not use control, shift, meta, alt, super, hyper bucky bits?

    > That would sum up to 26 bits per character.

27, by my count (assuming 21-bit codepoints rather than 20).

That's a good idea.   I'm not sure why I left out control.

Naming wise: having both "super" and "shift" bugs me.  What does "S-" mean?



    > Of course, while we are at it, why not just use 24 bits codepoints and 8
    > modifiers? Even if the extra codepoints and bits are not given any
    > special significance in Pika, they could come in handy for private use
    > by applications. Anyway, 21 bits chars or 26 bits chars are probably
    > going to be represented internally as 32 bits chars.

I'd like (21 + n_bucky_bits) to at least be < 29 -- leaving a minimum
of three tag bits if characters are immediate values (because there
are 8 bytes in a 2-word structure on a 32-bit machine).

But that still works out for having 8 modifiers (you listed 6 above).

Hmm.

       Control
       Shift
       Meta
       Alt
       Hyper
       ???              Gratuitous?
       ???              Excessive?
       ???              Ridiculous?


M-x describe-key RET R-S-M-H-G-E-C-A-x

  R-S-M-H-G-E-C-A-x runs the command dont-hurt-your-fingers
    which is an interactive built-in joke.

  Express admiration of your dexterity.
  With a prefix argument, display an essay about carpel tunnel
  syndrome.

  (dont-hurt-your-fingers N)


-t