iexpand.el

Expand commands at point

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Calls interactive functions from a typed symbol. This is cool because one can just type a symbol, and call iexpand, which will trigger the command if there is one associated with the symbol at point; the typed symbol will be deleted, restoring buffer state.

Users can define expansion tables in the spirit of abbrev tables — that is, in a per-mode fashion, respecting the hierarchy of modes.

Usage

(require 'iexpand)
(setq iexpand-default-key "RET") ; default is RET
(iexpand-global-mode t)
(iexpand-define 'emacs-lisp-mode "eb" #'eval-buffer)
(iexpand-define 'prog-mode "compile" #'compile)

Now in an emacs-lisp buffer, typing eb and calling iexpand (by default bound to RET) will evaluate the buffer. In that same buffer, as emacs-lisp-mode inherits from prog-mode, typing compile and calling iexpand will prompt for a compilation command (see C-h C-f compile).

One can also define multiple expansions in one run:

(iexpand-define-table 'text-mode
 "xs" #'save-buffer
 "ir" #'indent-region
 "indent-region" #'indent-region
 "indent" #'indent-region)

;; define global expansions by adding to the fundamental-mode table
(iexpand-define-table 'fundamental-mode
 "bb" #'switch-to-buffer
 "file" #'find-file
 "time" (lambda () (interactive) (message (format-time-string "%FT%T")))
 "timestamp" (lambda () (interactive) (insert  (format-time-string "%FT%T"))))

See it in action:

(For those who care, theme is a combination of modus operandi and elegance.el; font is Roboto mono.)

Installation

mkdir -p ~/.emacs.d/lib; git clone https://github.com/sam217pa/emacs-iexpand ~/.emacs.d/lib/iexpand

then in your init.el file:

(add-to-list 'load-path (expand-file-name "lib/iexpand" user-emacs-directory))
(require 'iexpand)

Why should you care?

As has been remarked to me on reddit, yasnippet or other packages implements something similar to what iexpand does. However, triggering arbitrary yet simple emacs-lisp commands from yasnippet requires you to 1) write a snippet with the propper (simple) syntax (yasnippet documentation), 2) save it to an appropriate place, 3) have yasnippet properly load the snippet (which it does automatically normally). It does work, but I do think that it is not what yasnippet was primarily intended to do, which is to expand plain text, with some assistance from emacs-lisp when need be.

Iexpand take it the other way around: it is primarily intended to evaluate emacs-lisp commands, which incidentally allows it to expand some simple text snippets. But I would keep writing snippets for anything more complex than what is displayed in the screencast (the timestamp snippet).

Another interesting aspect to me is that you can give plain text orders to emacs, say save, press return: it saves the buffer.

(iexpand-define 'prog-mode "stage" #'magit-stage-file)

type stage, press return, the file is staged. For some reason this “workflow” suits me well, maybe it'll suit you too.

Function Documentation

(iexpand-define-table MODE &rest BODY)

Wrapper around ‘iexpand-define’ for defining multiple KEY-COMMAND expansions.

BODY consists of KEY-COMMAND pairs.

Example: (iexpand-define-table ’emacs-lisp-mode "xs" #’save-buffer "hw" (lambda (interactive) (message "hello world")))

(iexpand-define MODE KEY COMMAND)

Define an expansion for COMMAND associated with KEY for MODE.

Calling ‘iexpand’ when point is after KEY in major-mode MODE triggers calling COMMAND interactively.

(iexpand &optional ARG)

Call command associated with symbol at point.

(iexpand-describe)

Describes the expansions associated with current ‘major-mode’.

(turn-on-iexpand-minor-mode)

Simple wrapper around ‘iexpand-minor-mode’

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