Emacs: abbrev-mode not expanding simple abbrev, possible causes?

Question

I would like to assign the string 'target="_blank"' to the abbreviation 'tgt' as I use this a lot and it's annoying to have to type out each time.

The string above probably needs escapes and so on, so as a simpler starting point I have tried to assign 'target' to 'tgt'. Despite switching on abbrev-mode and defining this as a global abbrev, if I type 'tgt' and hit space, nothing happens. If I do M-x list-abbrevs I get this:

(global-abbrev-table)

"target"       1    "tgt"

So it seems to be recorded. I would have expected tgt to be expanded to target when I hit a space after tgt, but that doesn't happen. What am I missing? Have I completely misunderstood the nature of abbrevs? I have looked at the Emacs wiki page but like many Emacs pages it gives a number of complex solutions and annoyingly sparse coverage of the basics.

EDIT: embarassingly enough this looks like it was a combination of the wrong abbrev file and an assignment that was reversed, so that typing 'target' produced 'tgt'. I now have 'tgt' producing 'target="_blank"' as desired. Apologies everybody.

However, I now have a related question. This abbreviation expands when I hit space and typically I do not want a space after the 'target="_blank"' string. Is there a way to automatically remove the space?

Answer 1

You have to define the abbrev the other way around. The way you did it will expand "target" into "tgt".

To do the right thing, first type into a buffer what you want the abbrev to expand into. In your case that would be "target". Then, with the point right after the word, type C-x a g. This will prompt you for an abbrev for which you would type "tgt".

Et voilà: if abbrev-mode is turned on, typing tgt will now expand into "target".

There are other ways to define an abbrev, e.g. via M-x define-global-abbrev, thus it's best to check out the documentation.

The problem with removing the space after the abbrev is that Emacs will insert it after the abbrev has been expanded. So hitting space will basically two things: trigger the expansion of the abbrev and then run the normal self-insert command.

One simple way to avoid this is to type C-x ' or C-x a e to explicitly expand an abbrev rather then turning on abbrev-mode. Except, that's a bit annoying. If we look at the documentation again, however, we find:

Function: define-abbrev table name expansion &optional hook count

[...]

If hook is a non-nil symbol whose no-self-insert property is non-nil, hook can explicitly control whether to insert the self-inserting input character that triggered the expansion. If hook returns non-nil in this case, that inhibits insertion of the character. By contrast, if hook returns nil, expand-abbrev also returns nil, as if expansion had not really occurred.

This means that if you put the following lines in, say, your ".emacs" file:

(defun my-after-abbrev-expand ()
  (when (looking-back "\"\"\\|''\\|()\\|\\[\\]\\|{}")
    (backward-char 1))
  t)
(put 'my-after-abbrev-expand 'no-self-insert t)

then you can define an abbrev like so:

(define-abbrev global-abbrev-table "tgt" "target=\"\"" 'my-after-abbrev-expand)

to avoid the insertion of the space character. Also, the my-after-abbrev-expand function will move the point one position to the left if the expansion ends in two double quotes, two single quotes, or a pair of round, square or curly braces.