Next: Abbrev Files, Previous: Abbrev Tables, Up: Abbrevs [Contents][Index]

### 35.2 Defining Abbrevs

`define-abbrev` is the low-level basic function for defining an abbrev in an abbrev table.

When a major mode defines a system abbrev, it should call `define-abbrev` and specify `t` for the `:system` property. Be aware that any saved non-system abbrevs are restored at startup, i.e., before some major modes are loaded. Therefore, major modes should not assume that their abbrev tables are empty when they are first loaded.

Function: define-abbrev abbrev-table name expansion &optional hook &rest props

  This function defines an abbrev named name, in abbrev-table, to expand to expansion and call hook, with properties props (see Abbrev Properties). The return value is name. The `:system` property in props is treated specially here: if it has the value `force`, then it will overwrite an existing definition even for a non-system abbrev of the same name.

  name should be a string. The argument expansion is normally the desired expansion (a string), or `nil` to undefine the abbrev. If it is anything but a string or `nil`, then the abbreviation expands solely by running hook.

  The argument hook is a function or `nil`. If hook is non-`nil`, then it is called with no arguments after the abbrev is replaced with expansion; point is located at the end of expansion when hook is called.

  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` (or `abbrev-insert`) also returns `nil`, as if expansion had not really occurred.

  Normally, `define-abbrev` sets the variable `abbrevs-changed` to `t`, if it actually changes the abbrev. This is so that some commands will offer to save the abbrevs. It does not do this for a system abbrev, since those aren’t saved anyway.

User Option: only-global-abbrevs

  If this variable is non-`nil`, it means that the user plans to use global abbrevs only. This tells the commands that define mode-specific abbrevs to define global ones instead. This variable does not alter the behavior of the functions in this section; it is examined by their callers.

Next: Abbrev Files, Previous: Abbrev Tables, Up: Abbrevs [Contents][Index]