compose-region docstring update (was: using glyphs by default in perl-mode)

[Ted Zlatanov]

On Fri, 07 Jun 2013 08:53:36 -0400 Kenichi Handa <address@hidden> wrote: 

KH> In article <address@hidden>, Eli Zaretskii <address@hidden>
KH> writes:
>> > From: Ted Zlatanov <address@hidden>
>> > Date: Wed, 05 Jun 2013 10:45:26 -0400
>> > 
>> > (Aside: I attempted to use `compose-region' to build more
>> > complicated
>> > compositions besides a single character.  The docstring says the
>> > COMPONENTS format can be several things, including:
KH> [...]
>> > 
>> > I stared at this for a while then I gave up.  It really needs one
>> > or two examples and an alternate wording, because I have no idea
>> > what it says.)

>> There's a reference to reference-point-alist, which I think has those
>> details.

KH> Yes.  And, here are simple examples:

KH> (insert (compose-string "." 0 1 '(?+ (tc . bc) ?o)))
KH> (insert (compose-string "." 0 1 '(?+ (cc . cc) ?o)))

Thanks for the examples.  Can you explain them (I think I do, but your
words would be welcome help)?  I will update the docstring once I
understand this well enough.

Ted