Re: did the abbrev mechanism ever expand «two words» to «two different words».

[Stefan Monnier]

>   An “abbrev” is a word that has been defined to “expand” into a specified
>   “expansion”.  When you insert a word-separator character following the
>   abbrev, that expands the abbrev—replacing the abbrev with its expansion.
>   For example, if ‘foo’ is defined as an abbrev expanding to ‘find outer
>   otter’, then typing ‘f o o .’ will insert ‘find outer otter.’.
>
> This mean a word-separator character cannot be part of an abbrev.

That's true for the default behavior.
Since Emacs-24, abbrev tables do support abbrevs whose name includes
non-word characters, but it requires extra work on the part of the user
in order to characterize the possible names via the `:regexp` property
(see `C-h o define-abbrev-table`).


        Stefan