Compose sequence standard

[John Meacham]

There is a standard, rfc1345, it is supported in several apps including
editors such as 'vim'. it would be nice if some terminal programs
supported them directly though... Although perhaps an X Input Method is
the way to do this.

see 
http://kaizi.viagenie.qc.ca/ietf/rfc/rfc1345.txt

        John


On Wed, Jun 04, 2003 at 12:51:54AM -0700, Alexandre Owen Muniz wrote:
> As modern unix desktops are moving toward unicode, it'd be nice if there 
> were standard
> compose sequences available to access a reasonable subset of unicode on 
> latin alphabet
> keyboards. (I'm thinking especially of American ones, simply because there 
> are quite a lot
> of them out there, and mine is one of them.)
> 
> A while back I made a stab at implementing a wider set of compose sequences 
> in gtk, but
> for this to really be useful it ought to be a standard across all X desktop 
> programs,
> which is why I am appealing to this forum.
> 
> I expect that it should be possible to expand my list a little, and I make 
> no guarantees
> that there aren't any outright bugs, but it's a starting point. My version 
> of the file in
> gtk with my expanded list of compose sequences is at:
> 
> http://www.xprt.net/~munizao/hacks/gtkimcontextsimple.c
> 
> The compose sequence table should be pretty self-explanatory even for 
> non-gtk folks.
> (This worked with gtk+ 2.0.6 and 2.0.7. I haven't had time to keep it up to 
> date.)
> 
> I tried to follow the following rules in coming up with my set of compose 
> sequences.
> 
> 1) Only two-character compose sequences are allowed.
> 
> 2) Preëxisting compose sequences used for the various Latin-n character 
> sets in X should
> be retained.
> 
> 3) Mnemonics for compose sequences should not be based on a particular 
> language. One
> example of such a mnemonic is 'v' + 'b' for vertical bar, (which is 
> retained due to 2.)
> 
> 4) Mnemonics for compose sequences should make sense visually. However, I'm 
> willing to
> bend this for the sake of coverage. (For example, I have 'o' + ':' → 
> 'ő'. I hope
> Hungarians will forgive me, but it was the best I could do.)
> 
> 5) Mnemonics for compose sequnces should be consistent. '<vowel>' + '-' 
> should always
> produce the <vowel> WITH MACRON character. But coverage should be weighed 
> against
> consistency. I added 's' + '-' → 'ſ', which might be a little 
> inconsistent, but it was the
> best sequence I could find to cover that character.
> 
> 6) Compose sequences should produce the same character as the corresponding 
> reversed
> sequences. (But not necessarily if reversing them breaks the mnemonic. For 
> example, ':' +
> ')' → '☺' (WHITE SMILING FACE) but ')' + ':' → '☹' (WHITE FROWNING 
> FACE))
> 
> 7) Sequences should cover:
> a) All characters in some ISO Latin-n set.
> b) All of the Latin Extended-A range.
> c) Characters for which there are compose sequences with mnemonics that are 
> analogous to
> those used in a) or b). For example:  '2' + '^' → '²', so '9' + '^' 
> should produce '⁹'.
> d) Characters that fill out the character gamuts of languages partially 
> covered by a, b,
> and c.
> e) Other characters which one might expect to be reasonably widely used and 
> for which
> reasonably intuitive mnemonics exist. These include mathematical symbols 
> like '≥', arrows,
>   characters in the Letterlike Symbols range like '℞' and '™', and a 
>   few others.
> 
> In some cases there will be conflicts where a given compose sequence might 
> reasonably
> apply to multiple characters. These should be decided on an ad hoc basis 
> where the
> wideness of use of the character, the intuitiveness of the compose 
> sequence, and the
> presence of reasonable alternative compose sequences for the character that 
> loses the
> conflict are all considered.
> 
> So, I want to know: would a standard expanded compose sequence list be used 
> if I were to
> make one, (with, of course, the input of concerned parties?) Are there 
> other factors that
> should be taken into account in developing such a list? I know that each 
> character added
> would add a few bytes of memory to the compose sequence tables. Is this 
> likely to be a
> problem?
> 
> **Ali
> 
> 
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-- 
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John Meacham - California Institute of Technology, Alum. - john at foo.net
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