Emacs Lisp Cheat Sheet

Special form

special form has its own rule for which arguments are evaluated

Special Form

Purpose	Forms
Definition	defconst defun defvar
Binding constructs	let let* function
Conditional evaluation	and cond if or
Sequential evaluation	prog1 prog2 progn
Iteration	while function
Syntactic extension	defmacro
Quoting	quote
Assignment	setq setq-default
Nonlocal Exits	catch condition-case unwind-protect
Save	save-current-buffer save-excursion save-restriction save-window-excursion
Other	interactive track-mouse with-output-to-temp-buffer

Standard Library

Including function, variable, command, option, macro, Special Form

Number

Emacs supports two numeric data types: integers and floating point numbers

Number related function and Variable

Category	Functions Variable
Integer Basics	most-positive-fixnum most-negative-fixnum
Floating Point Basics	logb float-e float-pi
Type Predicate Test	floatp integerp numberp wholenump zerop
Comparison	= eql /= < <= > >= max min abs
Conversions	float truncate floor ceiling round
Arithmetic Operations	1+ 1- + - * / % mod
Rounding Operations	ffloor fceiling ftruncate fround
Bitwise Operations	lsh ash logand logior logxor lognot
Mathematical Functions	sin cos tan asin acos atan exp log log10 expt sqrt
Random Numbers	random

String and Character

A string in Emacs Lisp is an array that contains an ordered sequence of characters

String and Character related function and Variable

Category	Functions Variable
Predicates for Strings	stringp string-or-null-p char-or-string-p
Creating Strings	make-string string substring substring-no-properties concat split-string split-string-default-separators
Modifying Strings	store-substring clear-string
Comparison	char-equal string= string-equal string< string-lessp compare-strings assoc-string
Conversion	number-to-string string-to-number char-to-string string-to-char
Formatting Strings	format
Case Conversion	downcase upcase capitalize upcase-initials
The Case Table	case-table-p set-standard-case-table standard-case-table current-case-table set-case-table with-case-table ascii-case-table set-case-syntax-pair set-case-syntax-delims set-case-syntax describe-buffer-case-table

Tip: you can also use a modern string manipulation library with s.el

List

Lists are built up from cons cells

List related function and Variable

Category	Functions Variable
List-related Predicates	consp atom listp nlistp null
List Elements	car cdr car-safe cdr-safe pop nth nthcdr last safe-length caar cadr cadr cadr butlast nbutlast
Building Lists	cons list make-list append reverse copy-tree number-sequence
List Variables	push add-to-list add-to-ordered-list
Modifying Lists	setcar setcdr nconc nreverse sort
Sets And Lists	memq delq remq memql member delete remove member-ignore-case delete-dups
Association Lists	assoc rassoc sassq rassq assoc-default copy-alist assq-delete-all rassq-delete-all
Rings	make-ring ring-p ring-size ring-length ring-elements ring-copy ring-empty-p ring-ref ring-insert ring-remove ring-insert-at-beginning

Tip: you can benefit from a modern list manipulation api with dash.el

Vector

Vector related function and Variable

Category	Functions Variable
Vector Functions	vectorp vector make-vector vconcat
Bool-vectors	make-bool-vector bool-vector-p

Sequence

sequence type is the union of two other Lisp types: lists and arrays. While array has four types, all one-dimensional: strings, vectors, bool-vectors, char-tables.

Sequence related function and Variable

Category	Functions Variable
Sequence Functions	sequencep length elt copy-sequence
Array Functions	arrayp aref aset fillarray
Char-Tables	make-char-table char-table-p char-table-subtype char-table-parent set-char-table-parent char-table-extra-slot set-char-table-extra-slot char-table-range set-char-table-range map-char-table

Hash Tables

Hash Tables related function and Variable

Category	Functions Variable
Creating Hash	make-hash-table makehash
Hash Access	gethash puthash remhash clrhash maphash
Defining Hash	define-hash-table-test sxhashsxhash
Other Hash	hash-table-p copy-hash-table hash-table-count hash-table-test hash-table-weakness hash-table-rehash-size hash-table-rehash-threshold hash-table-size

Symbols

Symbols related function and Variable

Category	Functions Variable
Predicates for symbols	symbolp
Creating Symbols	symbol-name make-symbol intern intern-soft obarray mapatoms unintern
Property Lists	symbol-plist setplist get put plist-get plist-put lax-plist-get lax-plist-put plist-member

Minibuffer

A minibuffer is a special buffer that Emacs commands use to read arguments more complicated than the single numeric prefix argument.

Minibuffer related function and Variable

Category	Functions Variable
Text from Minibuffer	read-from-minibuffer read-string read-regexp minibuffer-allow-text-properties minibuffer-local-map read-no-blanks-input minibuffer-local-ns-map
Object from Minibuffer	read-minibuffer eval-minibuffer edit-and-eval-command
Minibuffer History	add-to-history history-add-new-input history-length history-delete-duplicates minibuffer-history query-replace-history file-name-history buffer-name-history regexp-history extended-command-history shell-command-history read-expression-history
Basic Completion	try-completion all-completions test-completion completion-boundaries completion-ignore-case completion-regexp-list lazy-completion-table completion-in-region
Minibuffer Completion	completing-read
Completion Commands	minibuffer-completion-table minibuffer-completion-predicate minibuffer-completion-confirm minibuffer-confirm-exit-commands minibuffer-complete-word minibuffer-complete minibuffer-complete-and-exit minibuffer-completion-help display-completion-list completion-auto-help minibuffer-local-completion-map minibuffer-local-must-match-map minibuffer-local-filename-completion-map minibuffer-local-filename-must-match-map
High-Level Completion	read-buffer read-buffer-function read-buffer-completion-ignore-case read-command read-variable read-color
Reading File Names	read-file-name read-file-name-function read-file-name-completion-ignore-case read-directory-name insert-default-directory read-shell-command minibuffer-local-shell-command-map
Completion Styles	completion-styles completion-styles-alist
Programmed Completion	completion-table-dynamic completion-annotate-function
Yes-or-No Queries	y-or-n-p y-or-n-p-with-timeout yes-or-no-p
Multiple Queries	map-y-or-n-p
Reading a Password	read-passwd
Minibuffer Commands	exit-minibuffer self-insert-and-exit previous-history-element next-history-element previous-matching-history-element next-matching-history-element
Minibuffer Contents	minibuffer-prompt minibuffer-prompt-end minibuffer-prompt-width minibuffer-contents minibuffer-contents-no-properties minibuffer-completion-contents delete-minibuffer-contents
Minibuffer Windows	active-minibuffer-window minibuffer-window set-minibuffer-window window-minibuffer-p minibuffer-window-active-p
Recursive Mini	minibuffer-depth enable-recursive-minibuffers
Minibuffer Miscellany	minibufferp minibuffer-setup-hook minibuffer-exit-hook minibuffer-help-form minibuffer-scroll-window minibuffer-selected-window max-mini-window-height

Keymaps

Keymaps related function and Variable

Category	Functions Variable
Key Sequences	kbd
Format of Keymaps	keymapp
Creating Keymaps	make-sparse-keymap make-keymap copy-keymap
Inheritance and Keymaps	keymap-parent set-keymap-parent
Prefix Keys	define-prefix-command
Active Keymaps	current-active-maps key-binding
Controlling the Active Keymaps	global-map current-global-map current-local-map current-minor-mode-maps use-global-map use-local-map minor-mode-map-alist minor-mode-overriding-map-alist overriding-local-map overriding-terminal-local-map overriding-local-map-menu-flag special-event-map emulation-mode-map-alists
Functions for Key Lookup	lookup-key undefined local-key-binding global-key-binding minor-mode-key-binding meta-prefix-char
Changing Key Bindings	define-key substitute-key-definition suppress-keymap
Remapping Commands	command-remapping
Translation Keymaps	input-decode-map local-function-key-map key-translation-map
Key Binding Commands	global-set-key global-unset-key local-set-key local-unset-key
Scanning Keymaps	accessible-keymaps map-keymap where-is-internal describe-bindings
Menu Keymaps	keymap-prompt
Menus and the Keyboard	menu-prompt-more-char
Menu Bar	menu-bar-final-items menu-bar-update-hook
Tool Bar	tool-bar-map tool-bar-add-item tool-bar-add-item-from-menu tool-bar-local-item-from-menu auto-resize-tool-bars auto-raise-tool-bar-buttons tool-bar-button-margin tool-bar-button-relief tool-bar-border
Modifying Menus	define-key-after

File

File related function and Variable

Category	Functions Variable
Visiting Files	find-file find-file-literally find-file-noselect find-file-other-window find-file-read-only view-file find-file-wildcards find-file-hook find-file-not-found-functions find-file-literally create-file-buffer after-find-file
Saving Buffers	save-buffer save-some-buffers write-file write-file-functions write-contents-functions before-save-hook after-save-hook file-precious-flag require-final-newline
Reading from Files	insert-file-contents insert-file-contents-literally
Writing to Files	append-to-file write-region with-temp-file
File Locks	file-locked-p lock-buffer unlock-buffer ask-user-about-lock
Information about Files	file-exists-p file-readable-p file-executable-p file-writable-p file-accessible-directory-p access-file file-ownership-preserved-p file-newer-than-file-p file-symlink-p file-directory-p file-regular-p file-truename file-chase-links file-modes file-nlinks file-attributes locate-file executable-find
Changing Files	add-name-to-file rename-file copy-file make-symbolic-link delete-file set-file-modes set-default-file-modes default-file-modes read-file-modes file-modes-symbolic-to-number set-file-times
File Names	file-name-directory file-name-nondirectory file-name-sans-versions file-name-extension file-name-sans-extension file-name-absolute-p file-relative-name file-name-as-directory directory-file-name abbreviate-file-name expand-file-name default-directory substitute-in-file-name make-temp-file make-temp-name temporary-file-directory small-temporary-file-directory file-name-all-completions file-name-completion completion-ignored-extensions convert-standard-filename
Contents of Directories	directory-files directory-files-and-attributes file-expand-wildcards insert-directory insert-directory-program
Create/Delete Dirs	make-directory copy-directory delete-directory
Magic File Names	inhibit-file-name-handlers inhibit-file-name-operation find-file-name-handler file-local-copy file-remote-p unhandled-file-name-directory
Format Conversion	format-alist buffer-file-format format-write-file format-find-file format-insert-file buffer-auto-save-file-format write-region-annotate-functions write-region-post-annotation-function after-insert-file-functions

See also: f.el, a modern library for working with files and directories.

Buffer

buffer is a lisp object containing text to be edited

Buffer related function and Variable

Category	Functions Variable
Basic	bufferp current-buffer set-buffer save-current-buffer with-current-buffer with-temp-buffer
Buffer Names	buffer-name rename-buffer get-buffer generate-new-buffer-name
Buffer File Name	buffer-file-name buffer-file-name buffer-file-truename buffer-file-number get-file-buffer find-buffer-visting set-visted-file-name list-buffers-directory
Buffer Modification	buffer-modified-p set-buffer-modified-p restore-buffer-modified-p not-modified buffer-modified-tick buffer-chars-modified-tick
Buffer Modification Time	verify-visited-file-modtime clear-visited-file-modtime visited-file-modtime set-visited-file-modtime ask-user-about-supersession-threat
Read-Only Buffers	buffer-read-only inhibit-read-only toggle-read-only barf-if-buffer-read-only
Buffer List	buffer-list other-buffer last-buffer bury-buffer unbury-buffer
Creating Buffers	get-buffer-creat generate-new-buffer
Killing Buffers	kill-buffer kill-buffer-query-function kill-buffer-hook buffer-offer-save buffer-save-without-query buffer-live-p
Indirect Buffers	make-indirect-buffer clone-indirect-buffer buffer-base-buffer
Swapping Text Between Two Buffers	buffer-swap-text
Buffer Gap	gap-position gap-size

Windows

Windows related function and Variable

Category	Functions Variable
Basic Windows	windowp
Splitting Windows	split-window split-window-vertically split-window-keep-point split-window-horizontally one-window-p
Deleting Windows	window-live-p delete-window delete-other-windows delete-windows-on
Selecting Windows	selected-window select-window save-selected-window with-selected-window get-lru-window get-largest-window get-window-with-predicate
Cyclic Window Ordering	next-window previous-window other-window walk-windows window-list
Buffers and Windows	set-window-buffer buffer-display-count window-buffer get-buffer-window get-buffer-window-list buffer-display-time
Displaying Buffers	switch-to-buffer switch-to-buffer-other-window pop-to-buffer replace-buffer-in-windows
Choosing Window	display-buffer display-buffer-reuse-frames pop-up-windows split-window-preferred-function split-window-sensibly split-height-threshold split-width-threshold even-window-heights pop-up-frames pop-up-frame-function pop-up-frame-alist special-display-buffer-names special-display-regexps special-display-p special-display-function special-display-popup-frame special-display-frame-alist same-window-buffer-names same-window-regexps same-window-p display-buffer-function
Dedicated Windows	window-dedicated-p set-window-dedicated-p
Window Point	window-point set-window-point window-point-insertion-type
Window Start and End	window-start window-end set-window-start pos-visible-in-window-p window-line-height
Textual Scrolling	scroll-up scroll-down scroll-other-window other-window-scroll-buffer scroll-margin scroll-conservatively scroll-down-aggressively scroll-up-aggressively scroll-step scroll-preserve-screen-position next-screen-context-lines recenter
Vertical Scrolling	window-vscroll set-window-vscroll auto-window-vscroll
Horizontal Scrolling	scroll-left scroll-right window-hscroll set-window-hscroll
Size of Window	window-height window-body-height window-full-height-p window-width window-full-width-p window-edges window-inside-edges window-pixel-edges window-inside-pixel-edges
Resizing Windows	enlarge-window enlarge-window-horizontally shrink-window shrink-window-horizontally adjust-window-trailing-edge fit-window-to-buffer shrink-window-if-larger-than-buffer window-size-fixed window-min-height window-min-width balance-windows balance-windows-area
Coordinates and Windows	window-at coordinates-in-window-p
Window Tree	window-tree
Window Configurations	current-window-configuration set-window-configuration save-window-excursion window-configuration-p compare-window-configurations window-configuration-frame
Window Parameters	window-parameter window-parameters set-window-parameter
Window Hooks	window-scroll-functions window-size-change-functions window-configuration-change-hook

Frames

Frames related function and Variable

Category	Functions Variable
Creating Frames	make-frame before-make-frame-hook after-make-frame-functions frame-inherited-parameters
Multiple Terminals	terminal-name terminal-list get-device-terminal delete-terminal delete-terminal-functions make-frame-on-display x-display-list x-open-connection x-close-connection
Frame Parameters	frame-parameter frame-parameters modify-frame-parameters set-frame-parameter modify-all-frames-parameters initial-frame-alist minibuffer-frame-alist default-frame-alist blink-cursor-alist cursor-in-non-selected-windows set-frame-position frame-height frame-width frame-pixel-height frame-pixel-width frame-char-height frame-char-width set-frame-size set-frame-height set-frame-width x-parse-geometry
Terminal Parameters	terminal-parameters terminal-parameter set-terminal-parameter
Frame Titles	frame-title-format icon-title-format multiple-frames
Deleting Frames	delete-frame frame-live-p
Finding All Frames	frame-list visible-frame-list next-frame previous-frame
Frames and Windows	window-frame frame-first-window frame-selected-window set-frame-selected-window
Minibuffers and Frames	default-minibuffer-frame
Input Focus	selected-frame select-frame-set-input-focus select-frame handle-switch-frame redirect-frame-focus focus-follows-mouse
Visibility of Frames	make-frame-visible make-frame-invisible iconify-frame frame-visible-p
Raising and Lowering	raise-frame lower-frame minibuffer-auto-raise
Frame Configurations	current-frame-configuration set-frame-configuration
Mouse Tracking	track-mouse
Mouse Position	mouse-position mouse-position-function set-mouse-position mouse-pixel-position set-mouse-pixel-position
Pop-Up Menus	x-popup-menu
Dialog Boxes	x-popup-dialog
Pointer Shape	void-text-area-pointer x-pointer-shape x-sensitive-text-pointer-shape
Window System Selections	x-set-selection x-get-selection x-get-cut-buffer x-set-cut-buffer selection-coding-system x-select-enable-clipboard
Color Names	color-defined-p defined-colors color-supported-p color-gray-p color-values
Text Terminal Colors	tty-color-define tty-color-clear tty-color-alist tty-color-approximate tty-color-translate
Resources	x-get-resource x-resource-class x-resource-name inhibit-x-resources
Display Feature Testing	display-popup-menus-p display-graphic-p display-mouse-p display-color-p display-grayscale-p display-supports-face-attributes-p display-selections-p display-images-p display-screens display-pixel-height display-pixel-width display-mm-height display-mm-width display-mm-dimensions-alist display-backing-store display-save-under display-planes display-visual-class display-color-cells x-server-version x-server-vendor

Positions

A position is the index of a character in the text of a buffer.

Positions related function and Variable

Category	Functions Variable
Point	point point-min point-max buffer-end buffer-size
Motion	goto-char forward-char backward-char
	forward-word backward-word words-include-escapes inhibit-field-text-motion
	beginning-of-buffer end-of-buffer
	beginning-of-line line-beginning-position end-of-line line-end-position forward-line count-lines line-number-at-pos
	vertical-motion count-screen-lines move-to-window-line compute-motion
	forward-list backward-list up-list down-list forward-sexp backward-sexp beginning-of-defun end-of-defun defun-prompt-regexp open-paren-in-column-0-is-defun-start beginning-of-defun-function end-of-defun-function
	skip-chars-forward skip-chars-backward
Excursions	save-excursion
Narrowing	narrow-to-region narrow-to-page widen save-restriction

Marker

A marker is a Lisp object used to specify a position in a buffer relative to the surrounding text.

Marker related function and Variable

Category	Functions Variable
Predicates on Markers	markerp integer-or-marker-p number-or-marker-p
Creating Markers	make-marker point-marker point-min-marker point-max-marker copy-marker
Information from Markers	marker-position marker-buffer buffer-has-markers-at
Marker Insertion Types	set-marker-insertion-type marker-insertion-type
Moving Markers	set-marker move-marker
The Mark	mark mark-marker set-mark push-mark pop-mark transient-mark-mode mark-even-if-inactive deactivate-mark deactivate-mark mark-active activate-mark-hook deactivate-mark-hook handle-shift-selection mark-ring mark-ring-max
The Region	region-beginning region-end use-region-p

Text

Text is manipulated through Buffer object with point and marker.

Text related function and Variable

Category	Function Variable
Near Point	char-after char-before following-char preceding-char bobp eobp bolp eolp
Examining Buffer Contents	buffer-substring buffer-substring-no-properties buffer-string filter-buffer-substring filter-buffer-substring-function buffer-substring-filters current-word thing-at-point
Comparing Text	compare-buffer-substrings
Inserting Text	insert insert-before-markers insert-char insert-buffer-substring insert-buffer-substring-no-properties
User-Level Insertion Commands	insert-buffer self-insert-command newline overwrite-mode
Deleting Text	erase-buffer delete-region delete-and-extract-region delete-char delete-backward-char backwar-delete-char-untabify backward-delete-char-untabify-method
User-Level Deletion Commands	delete-horizontal-space delete-indentation fixup-whitespace just-one-space delete-blank-lines
The Kill Ring	kill-region kill-read-only-ok copy-region-as-kill insert-for-yank insert-buffer-substring-as-yank yank yank-pop yank-undo-function current-kill kill-new kill-append interprogram-paste-function interprogram-cut-function kill-ring kill-ring-yank-pointer kill-ring-max
Undo	buffer-undo-list undo-boundary undo-in-progress primitive-undo
Maintaining Undo Lists	buffer-enable-undo buffer-disable-undo undo-limit undo-strong-limit undo-outer-limit undo-ask-before-discard
Filling	fill-paragraph fill-region fill-individual-paragraphs fill-individual-varying-indent fill-region-as-paragraph justify-current-line default-justification current-justification sentence-end-double-space sentence-end-without-period sentence-end-without-space fill-paragraph-function fill-forward-paragraph-function use-hard-newlines
Margins	fill-prefix fill-column set-left-margin set-right-margin current-left-margin current-fill-column move-to-left-margin delete-to-left-margin indent-to-left-margin left-margin fill-nobreak-predicate
Adaptive Fill	adaptive-fill-mode fill-context-prefix adaptive-fill-regexp adaptive-fill-first-line-regexp adaptive-fill-function
Auto Filling	auto-fill-function normal-auto-fill-function auto-fill-chars
Sorting	sort-subr sort-fold-case sort-regexp-fields sort-regexp-fields sort-paragraphs sort-pages sort-fields sort-numeric-fields sort-numeric-base sort-columns
Columns	current-column move-to-column
Indentation	current-indentation indent-to indent-tabs-mode indent-line-function indent-according-to-mode indent-for-tab-command newline-and-indent reindent-then-newline-and-indent indent-region indent-region-function indent-rigidly indent-code-rigidly indent-relative indent-relative-maybe tab-to-tab-stop tab-stop-list back-to-indentation backward-to-indentation forward-to-indentation
Case	capitalize-region downcase-region upcase-region capitalize-word downcase-word upcase-word
Text Properties	get-text-property get-char-property get-char-property-and-overlay char-property-alias-alist text-properties-at default-text-properties put-text-property add-text-properties remove-text-properties remove-list-of-text-properties set-text-properties propertize next-property-change previous-property-change next-single-property-change previous-single-property-change next-char-property-change previous-char-property-change next-single-char-property-change previous-single-char-property-change text-property-any text-property-not-all inhibit-point-motion-hooks show-help-function text-property-default-nonsticky insert-and-inherit insert-before-markers-and-inherit buffer-access-fontify-functions buffer-access-fontified-property mouse-on-link-p field-beginning field-end field-string field-string-no-properties delete-field constrain-to-field
Substituting	subst-char-in-region translate-region
Transposition	transpose-regions
Registers	register-alist get-register set-register view-register insert-register
Base 64	base64-encode-region base64-encode-string base64-decode-region base64-decode-string
MD5 Checksum	md5
Atomic Change	prepare-change-group activate-change-group accept-change-group cancel-change-group
Change Hooks	before-change-functions after-change-functions combine-after-change-calls first-change-hook inhibit-modification-hooks

Searching and Matching

Searching and Matching related function and Variable

Category	Function Variable
String Search	search-forward search-backward word-search-forward word-search-forward-lax word-search-backward word-search-backward-lax
Searching and Case	Case-independent or case-significant searching. case-fold-search case-replace
Regular Expressions	regexp-quote regexp-opt regexp-opt-depth
Regexp Search	re-search-forward re-search-backward string-match string-match-p looking-at looking-back looking-at-p search-spaces-regexp
POSIX Regexps	posix-search-forward posix-search-backward posix-looking-at posix-string-match
Match Data	replace-match match-substitute-replacement match-string match-string-no-properties match-beginning match-end match-data set-match-data save-match-data
Search and Replace	replace-regexp-in-string perform-replace query-replace-map
Standard Regexps	page-delimiter paragraph-separate paragraph-start sentence-end sentence-end

Processes

Processes related function and Variable

Category	Functions Variable
Process Predicate	processp
Subprocess Creation	exec-suffixes exec-directory exec-path
Shell Arguments	shell-quote-argument split-string-and-unquote combine-and-quote-strings
Synchronous Processes	call-process process-file process-file-side-effects call-process-region call-process-shell-command process-file-shell-command shell-command-to-string process-lines
Asynchronous Processes	start-process start-file-process start-process-shell-command start-file-process-shell-command process-connection-type
Deleting Processes	delete-exited-processes delete-process
Process Information	list-processes process-list get-process process-command process-contact process-id process-name process-status process-type process-exit-status process-tty-name process-coding-system set-process-coding-system process-get process-put process-plist set-process-plist
Input to Processes	process-send-string process-send-region process-send-eof process-running-child-p
Signals to Processes	interrupt-process kill-process quit-process stop-process continue-process signal-process
Output from Processes	process-adaptive-read-buffering process-buffer process-mark set-process-buffer get-buffer-process set-process-filter process-filter accept-process-output
Sentinels	set-process-sentinel process-sentinel waiting-for-user-input-p
Query Before Exit	process-query-on-exit-flag set-process-query-on-exit-flag process-kill-without-query
System Processes	list-system-processes process-attributes
Transaction Queues	tq-create tq-enqueue tq-close
Network	open-network-stream
Datagrams	process-datagram-address set-process-datagram-address
Low-Level Network	make-network-process set-network-process-option
Misc Network	network-interface-list network-interface-info format-network-address
Serial Ports	serial-term make-serial-process serial-process-configure
Byte Packing	bindat-unpack bindat-get-field bindat-length bindat-pack bindat-ip-to-string

System Interface

System Interface related function and Variable

Category	Functions Variable
Starting Up	inhibit-startup-screen initial-buffer-choice inhibit-startup-echo-area-message initial-scratch-message site-run-file inhibit-default-init before-init-hook after-init-hook emacs-startup-hook user-init-file user-emacs-directory term-file-prefix term-setup-hook command-line command-line-processed command-switch-alist command-line-args command-line-args-left command-line-functions
Getting Out	kill-emacs kill-emacs-query-functions kill-emacs-hook suspend-emacs suspend-hook suspend-resume-hook suspend-tty resume-tty controlling-tty-p suspend-frame
System Environment	system-configuration system-type system-name mail-host-address getenv setenv process-environment initial-environment path-separator parse-colon-path invocation-name invocation-directory installation-directory load-average emacs-pid emacs-pid
User Identification	init-file-user user-mail-address user-login-name user-real-login-name user-full-name user-real-uid user-uid
Time of Day	current-time-string current-time current-time-zone set-time-zone-rule float-time
Time Conversion	decode-time encode-time
Time Parsing	date-to-time format-time-string seconds-to-time format-seconds
Processor Run Time	emacs-uptime get-internal-run-time emacs-init-time
Time Calculations	time-less-p time-subtract time-add time-to-days time-to-day-in-year date-leap-year-p
Timers	run-at-time timer-max-repeats with-timeout cancel-timer
Idle Timers	run-with-idle-timer current-idle-time
Terminal Input	set-input-mode current-input-mode recent-keys open-dribble-file
Terminal Output	baud-rate send-string-to-terminal open-termscript
Sound Output	play-sound play-sound-file play-sound-functions
X11 Keysyms	system-key-alist x-alt-keysym x-meta-keysym x-hyper-keysym x-super-keysym
Batch Mode	noninteractive
Session Management	emacs-save-session-functions

Display

Display related function and Variable

Category	Functions Variable
Refresh Screen	redraw-frame redraw-display no-redraw-on-reenter
Forcing Redisplay	redisplay force-window-update redisplay-dont-pause redisplay-preemption-period
Truncation	truncate-lines truncate-partial-width-windows wrap-prefix line-prefix cache-long-line-scans
The Echo Area	message with-temp-message message-or-box message-box display-message-or-buffer current-message make-progress-reporter progress-reporter-update progress-reporter-force-update progress-reporter-done dotimes-with-progress-reporter message-log-max cursor-in-echo-area echo-area-clear-hook echo-keystrokes message-truncate-lines cursor-in-echo-area echo-area-clear-hook echo-keystrokes message-truncate-lines
Warnings	display-warning lwarn warn warning-levels warning-prefix-function warning-series warning-fill-prefix warning-type-format warning-minimum-level warning-minimum-log-level warning-suppress-types warning-suppress-log-types
Invisible Text	buffer-invisibility-spec add-to-invisibility-spec remove-from-invisibility-spec invisible-p
Selective Display	selective-display selective-display-ellipses
Temporary Displays	with-output-to-temp-buffer temp-buffer-show-function temp-buffer-setup-hook temp-buffer-show-hook momentary-string-display
Overlays	overlayp make-overlay overlay-start overlay-end overlay-buffer delete-overlay move-overlay remove-overlays copy-overlay overlay-recenter overlay-get overlay-put overlay-properties overlays-at overlays-in next-overlay-change previous-overlay-change
Width	char-width string-width truncate-string-to-width
Faces	facep defface
	frame-background-mode
	font-family-list underline-minimum-offset x-bitmap-file-path bitmap-spec-p
	set-face-attribute face-attribute face-attribute-relative-p face-all-attributes merge-face-attribute set-face-foreground set-face-background set-face-stipple set-face-font set-face-bold-p set-face-italic-p set-face-underline-p set-face-inverse-video-p
	invert-face face-remapping-alist face-remap-add-relative face-remap-remove-relative face-remap-set-base face-remap-reset-base
	make-face face-list copy-face face-id face-documentation face-equal face-differs-from-default-p define-obsolete-face-alias
	fontification-functions
	face-font-family-alternatives face-font-selection-order face-font-registry-alternatives
	scalable-fonts-allowed face-font-rescale-alist x-list-fonts x-family-fonts font-list-limit
	create-fontset-from-fontset-spec set-fontset-font char-displayable-p
	fontp font-at font-spec font-put find-font list-fonts font-get font-face-attributes font-xlfd-name
Fringes	fringes-outside-margins left-fringe-width right-fringe-width set-window-fringes window-fringes indicate-empty-lines indicate-buffer-boundaries fringe-indicator-alist overflow-newline-into-fringe fringe-cursor-alist fringe-bitmaps-at-pos define-fringe-bitmap destroy-fringe-bitmap set-fringe-bitmap-face overlay-arrow-string overlay-arrow-position overlay-arrow-variable-list
Scroll Bars	frame-current-scroll-bars set-window-scroll-bars window-scroll-bars scroll-bar-mode window-current-scroll-bars scroll-bar-width
Display Property	left-margin-width right-margin-width set-window-margins window-margins
Images	image-types image-library-alist image-type-available-p image-mask-p create-image defimage find-image image-load-path image-load-path-for-library insert-image insert-sliced-image put-image remove-images image-size max-image-size image-refresh clear-image-cache image-cache-eviction-delay
Buttons	define-button-type make-button insert-button make-text-button insert-text-button button-start button-end button-get button-put button-activate button-label button-type button-has-type-p button-at button-type-put button-type-get button-type-subtype-p push-button forward-button backward-button next-button previous-button
Abstract Display	ewoc-create ewoc-buffer ewoc-get-hf ewoc-set-hf ewoc-enter-first ewoc-enter-last ewoc-enter-before ewoc-enter-after ewoc-prev ewoc-next ewoc-nth ewoc-data ewoc-set-data ewoc-locate ewoc-location ewoc-goto-prev ewoc-goto-next ewoc-goto-node ewoc-refresh ewoc-invalidate ewoc-delete ewoc-filter ewoc-collect ewoc-map
Blinking	blink-paren-function blink-matching-paren blink-matching-paren-distance blink-matching-delay blink-matching-open
Usual Display	ctl-arrow tab-width
Display Tables	make-display-table display-table-slot set-display-table-slot describe-display-table describe-current-display-table window-display-table set-window-display-table buffer-display-table standard-display-table make-glyph-code glyph-char glyph-face glyph-table create-glyph
Beeping	ding beep visible-bell ring-bell-function
Window Systems	window-system initial-window-system window-system window-setup-hook

Third party libraries

s.el, a string manipulation library

s.el is a modern string manipulation api. It's available on marmalade and Melpa.

dash.el, a modern list library

dash.el is a modern list library for emacs. It's available on marmalade and Melpa.