bug#358: dabbrev-abbrev-char-regexp

[Noam Postavsky <npostavs@users.sourceforge.net>]

On Thu, Mar 23, 2017 at 4:58 PM, Drew Adams <drew.adams@oracle.com> wrote:
>
> Of course, the problem here is that we are talking about expanding
> `yes-or-no-p', which in Lisp is a Lisp symbol.  It would probably
> be better to talk about using dabbrev in another context, besides
> Lisp.  Then it would be clearer that we are talking only about
> symbol vs word syntax.

As in, use a C example instead?

For instance, suppose the current buffer is in `c-mode'.  If this
variable is nil or \"\\\\sw\\\\|\\\\s_\", then expanding
`debug_print_in_' looks for a symbol starting with
`debug_print_in_'.  If you set this variable to \"\\\\sw\", that
expansion looks for a word prefixed with `in_' (e.g., it would
match `in_range', but not `in_close_range').  If expanding
`debug_print_in' it would look for a word starting with
`in' (e.g. `integer')."