#Femto Emacs Femto is an extended version of Atto Emacs.
A designer knows he has achieved perfection not when there is nothing left to add, but when there is nothing left to take away. -- Antoine de Saint-Exupery
##Goals of Femto Emacs
- To extend Atto Emacs with filename completion, dired, buffer menu and the ability to run a shell command.
- Provide a rich level of functionality in the smallest amount of code
- Femto Emacs will eventually have it own lisp extension languauge.
- Be easy to understand without extensive study (to encourage further experimentation).
##Why the name Femto? Femto is an extended version of Atto Emacs.
In Defining Atto as the lowest functional Emacs I have had to consider the essential feature set that makes Emacs, 'Emacs'. I have defined this point as a basic Emacs command set and key bindings; the ability to edit multiple files (buffers), and switch between them; edit the buffers in mutliple windows, cut, copy and paste; forward and reverse searching and a replace function. The proviso being that all this will fit in less than 2000 lines of C.
The small Emacs naming scheme appears to use sub-unit prefixes in decending order with each further reduction of functionality.
Atto means 10 to the power of minus 18.
An extended Atto would therefore be called Femto (10 to the power of minus 15).
##Derivation Femto is based on the Atto codebase [0] (as of Atto 1.6) Atto was based on the public domain code of Anthony Howe's editor (commonly known as Anthony's Editor or AE, [2]).
- Added automatic matching of parenthesis {}() and []
- Fixed bug where a new file created when file not found did not have a buffer created
- Initialised buffer name to empty string
- Added basic colour scheme
- Fixed defect with paste command introduced in v1.1
- Added messages on copy and cut to show how many bytes
- Added UTF8 support
- Added list-buffers C-x C-b
- fixed problem of opening up multiple output windows
- refactored paste. Paste now calls insert-string with contents of scrap
- Added filename completion (use TAB to complete)
- Added shell-command (C-x @), output is read into a buffer
##Comparisons with Other Emacs Implementations
Editor Binary BinSize KLOC Files
femto femto 43397 2.1k 11
atto atto 33002 1.9k 10
pEmacs pe 59465 5.7K 16
Esatz-Emacs ee 59050 5.7K 14
GNOME GNOME 55922 9.8k 13
Zile zile 257360 11.7k 48
Mg mg 585313 16.5K 50
uEmacs/Pk em 147546 17.5K 34
Pico pico 438534 24.0k 29
Nano nano 192008 24.8K 17
jove jove 248824 34.7k 94
Qemacs qe 379968 36.9k 59
ue3.10 uemacs 171664 52.4K 16
GNUEmacs emacs 14632920 358.0k 186
##Femto Key Bindings C-A begining-of-line C-B backward-character C-D delete-char C-E end-of-line C-F forward Character C-G Abort (at prompts) C-H backspace C-I handle-tab C-J newline C-K kill-to-eol C-L refresh display C-M Carrage Return C-N next line C-P previous line C-R search-backwards C-S search-forwards C-U Undo C-V Page Down C-W Kill Region (Cut) C-X CTRL-X command prefix C-Y Yank (Paste)
M-< Start of file
M-> End of file
M-v Page Up
M-f Forward Word
M-b Backwards Word
M-g goto-line
M-r Search and Replace
M-w copy-region
C-<spacebar> Set mark at current position.
C-x C-b List Buffers
C-x C-c Exit. Any unsaved files will require confirmation.
C-x C-f Find file; read into a new buffer created from filename.
C-x C-s Save current buffer to disk, using the buffer's filename as the name of
C-x C-w Write current buffer to disk. Type in a new filename at the prompt to
C-x @ shell-command (you are prompted for a command which is sent to the shell
and the result is displayed in the *output* buffer
C-x i Insert file at point
C-x = Show Character at position
C-x C-n next-buffer
C-x n next-buffer
C-x k kill-buffer
C-x 1 delete-other-windows
C-x 2 split-window
C-x o other-window
Home Beginning-of-line
End End-of-line
Del Delete character under cursor
Ins Toggle Overwrite Mode
Left Move left
Right Move point right
Up Move to the previous line
Down Move to the next line
Backspace delete caharacter on the left
Ctrl+Up beginning of file
Ctrl+Down end of file
Ctrk+Left Page Down
Ctrl+Right Page Up
###Copying and moving C- Set mark at current position C-x Delete region C-y Yank back kill buffer at cursor M-w Copy Region
A region is defined as the area between this mark and the current cursor position. The kill buffer is the text which has been most recently deleted or copied.
Generally, the procedure for copying or moving text is:
- Mark out region using M- at the beginning and move the cursor to the end.
- Delete it (with ^W) or copy it (with M-W) into the kill buffer.
- Move the cursor to the desired location and yank it back (with ^Y).
###Searching C-S or C-R enters the search prompt, where you type the search string BACKSPACE - will reduce the search string, any other character will extend it C-S at the search prompt will search forward, will wrap at end of the buffer C-R at the search prompt will search backwards, will wrap at start of the buffer ESC will escape from the search prompt and return to the point of the match C-G abort the search and return to point before the search started
##Building on Ubuntu
When building on Ubuntu you will need to install the libcurses dev package. NOTE: As of Femto 1.2 you will also need the libncursesw (wide) library
$ sudo apt-get install apt-file $ apt-file update
now search for which package would have curses.h $ apt-file search curses.h
libncurses5-dev: /usr/include/curses.h
$ sudo apt-get install libncurses5-dev libncursesw5-dev
##Future Enhancements
The following enhancements are envisaged.
- A buffer menu facility
- Directory and file manegement (Dired) functionality.
- A Lisp or Scheme based extension languauge.
##Known Issues Goto-line will fail to go to the very last line. This is a special case that could easily be fixed.
##Copying Femto code is released to the public domain. hughbarney@gmail.com May 2016
##References [0] Atto Emacs - https://github.com/hughbarney/atto [1] Perfect Emacs - https://github.com/hughbarney/pEmacs [2] Anthony's Editor - https://github.com/hughbarney/Anthony-s-Editor [3] MG - https://github.com/rzalamena/mg [4] Jonathan Payne, Buffer-Gap: http://ned.rubyforge.org/doc/buffer-gap.txt [5] Anthony Howe, http://ned.rubyforge.org/doc/editor-101.txt [6] Anthony Howe, http://ned.rubyforge.org/doc/editor-102.txt