Compositions documentation

Compositions documentation

[Eli Zaretskii]

I see that the Lisp APIs that deal with compositions
(composition-get-gstring, compose-region, compose-string,
find-composition, etc.) are not documented in the ELisp manual.
Should they be?  Or are these APIs so obscure that no one should futz
with them?

Re: Compositions documentation

[Stefan Monnier]

> I see that the Lisp APIs that deal with compositions
> (composition-get-gstring, compose-region, compose-string,
> find-composition, etc.) are not documented in the ELisp manual.
> Should they be?  Or are these APIs so obscure that no one should futz
> with them?

FWIW, `compose-region' is used in the "pretty lambda" trick, which
I have adapted to sml-mode, haskell-mode, and a bunch of others.


        Stefan

Re: Compositions documentation

[Kenichi Handa]

In article <umycztwrm.fsf@gnu.org>, Eli Zaretskii <eliz@gnu.org> writes:

> I see that the Lisp APIs that deal with compositions
> (composition-get-gstring, compose-region, compose-string,
> find-composition, etc.) are not documented in the ELisp manual.
> Should they be?  Or are these APIs so obscure that no one should futz
> with them?

Compose-region and compose-string are described in
etc/NEWS.21 as this:

*** The function `compose-region' takes new arguments COMPONENTS and
MODIFICATION-FUNC.  With COMPONENTS, you can specify not only a
composition rule but also characters to be composed.  Such characters
may differ between buffer and string text.

*** The function `compose-string' takes new arguments START, END,
COMPONENTS, and MODIFICATION-FUNC.

*** The function `compose-string' puts text property `composition'
directly on the argument STRING instead of returning a new string.
Likewise, the function `decompose-string' just removes text property
`composition' from STRING.

*** The new function `find-composition' returns information about
a composition at a specified position in a buffer or a string.

If they are not documented now, perhaps RMS decided that
it's not worthwhile.  But, I think it is better to document
them.

On the other hand, composition-get-gstring and the other
several new functions in composite.el are only for Emacs
internal.

---
Kenichi Handa
handa@m17n.org