36.3 Defining Abbrevs

These functions define an abbrev in a specified abbrev table. define-abbrev is the low-level basic function, while add-abbrev is used by commands that ask for information from the user.

Function: add-abbrev table type arg

This function adds an abbreviation to abbrev table table based on information from the user. The argument type is a string describing in English the kind of abbrev this will be (typically, "global" or "mode-specific"); this is used in prompting the user. The argument arg is the number of words in the expansion.

The return value is the symbol that internally represents the new abbrev, or nil if the user declines to confirm redefining an existing abbrev.

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

This function defines an abbrev named name, in table, to expand to expansion and call hook. The value of count, if specified, initializes the abbrev's usage-count. If count is not specified or nil, the use count is initialized to zero. The return value is a symbol that represents the abbrev inside Emacs; its name is name.

The argument 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 also returns nil, as if expansion had not really occurred.

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.