Alternatives to . for composition

[Jon Fairbairn]

On 2006-03-25 at 09:41PST "Jared Updike" wrote:
> > 2218      RING OPERATOR
> >           = composite function
> >           = APL jot
> >             00B0 degree sign
> >             25E6 white bullet
> >
> > I don't think any other Unicode character should be considered.
> 
> That's great but
> 1) I have no idea how to type it. Can I easily and comfortably? In emacs?

For emacs, just bind a key (C-. say) to (ucs-insert
 #X2218). ucs-insert comes from ucs-tables.

> 2) Will it show up in PuTTY (and everyone else's terminals/IDEs)?

Eventually.

> in everyone's mail readers (including Gmail)?

Eventually, I should think. I'm using nmh, which has to be
one of the least trendy MUAs about, and that can do it. What
does this: ∘ look like in your email reader?

> 3) What encoding do my textfiles need to be in

Probably utf-8

> (i.e. how many bytes per char)?

a bit more than one on average.

> How do I do that?

Depends on the OS you are using. I've got locale set to
en_GB.UTF-8 and it all more or less works.

> Does Haskell even support everything related to Unicode
> that we'd need?

Not now, but Haskell' jolly well ought to.

> If the answers are satisfactory to all these questions,
> then Unicode is a good idea (and that's the ideal
> character).

"Satisfactory" is in the eye of the beholder.

> If not, we're sadly stuck in ASCII land.

It's far worse than that. We are stuck in an idiotic land
where the meaning of a file depends on the meaning of a user
settable variable in the OS. This is one of the many
unpleasant consequences of untyped filesystems¹.  Oh, and
Haskell claims already to have unicode source files, but the
compilers can't handle it.

>   Jared.
> 
> P.S. Plus that opens a lot of cans of worms for writing programs with
> all those fancy symbols! APL here we come!

It's a question of good style, isn't it? Using → instead of
-> might be nice, but stringing together lots of arcane
symbols like ₀∘°⁰ wouldn't be.  For Haskell 98 I argued
against unicode, preferring that we should stick with ASCII,
but nowadays a language that doesn't handle unicode properly
is going to look shabby in a few years.

 Jón

[1] Something about which something should be done in
Haskell...

-- 
Jón Fairbairn                              Jon.Fairbairn at cl.cam.ac.uk