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An Introduction to Programming in Emacs Lisp

Name: An Introduction to Programming in Emacs Lisp
ISBN: 1-882114-43-4

By Robert .J Chassell

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Book Description

This tutorial is an elementary introduction to teach non-programmers how to customize their work environment; it can also be used as an introduction to programming basics. It includes numerous exercises and sample programs; the author also walks you through the actual source code of several GNU Emacs commands. A handy reference appendix is included.

Emacs Lisp is a simple, complete, and powerful programming language. It is the building block of GNU Emacs, which is an integrated development environment with special features for scanning and parsing text as well as for handling multiple files, buffers, displays, windows, and sub-processors.

This text will show you:

how to set variables and write function definitions

How to use "if" and "let"

How to write "while" loops and recursive loops

How to search for a word or expression

How to customize GNU Emacs for yourself, even when it is shared on a network.

How to debug programs

and much more.
This revised third edition covers new features included in GNU Emacs version 21, while remaining compatible with earlier versions.

Print copies available for purchase from the Free Software Foundation.

Table of Contents

Preface
- On Reading this Text
- For Whom This is Written
- Lisp History
- A Note for Novices
- Thank You
List Processing
- Lisp Lists
  - Lisp Atoms
  - Whitespace in Lists
  - GNU Emacs Helps You Type Lists
- Run a Program
- Generate an Error Message
- Symbol Names and Function Definitions
- The Lisp Interpreter
  - Byte Compiling
- Evaluation
  - Evaluating Inner Lists
- Variables
  - Error Message for a Symbol Without a Function
  - Error Message for a Symbol Without a Value
- Arguments
  - Arguments' Data Types
  - An Argument as the Value of a Variable or List
  - Variable Number of Arguments
  - Using the Wrong Type Object as an Argument
  - The message Function
- Setting the Value of a Variable
  - Using set
  - Using setq
  - Counting
- Summary
- Exercises
Practicing Evaluation
- Buffer Names
- Getting Buffers
- Switching Buffers
- Buffer Size and the Location of Point
- Exercise
How To Write Function Definitions
- The defun Macro
- Install a Function Definition
  - Change a Function Definition
- Make a Function Interactive
  - An Interactive multiply-by-seven
- Different Options for interactive
- Install Code Permanently
- let
  - The Parts of a let Expression
  - Sample let Expression
  - Uninitialized Variables in a let Statement
- The if Special Form
  - The type-of-animal Function in Detail
- If--then--else Expressions
- Truth and Falsehood in Emacs Lisp
- save-excursion
  - Template for a save-excursion Expression
- Review
- Exercises
A Few Buffer--Related Functions
- Finding More Information
- A Simplified beginning-of-buffer Definition
- The Definition of mark-whole-buffer
  - Body of mark-whole-buffer
- The Definition of append-to-buffer
  - The append-to-buffer Interactive Expression
  - The Body of append-to-buffer
  - save-excursion in append-to-buffer
- Review
- Exercises
A Few More Complex Functions
- The Definition of copy-to-buffer
- The Definition of insert-buffer
  - The Interactive Expression in insert-buffer
    - A Read-only Buffer
    - b in an Interactive Expression
  - The Body of the insert-buffer Function
  - insert-buffer With an if Instead of an or
  - The or in the Body
  - The let Expression in insert-buffer
  - New Body for insert-buffer
- Complete Definition of beginning-of-buffer
  - Optional Arguments
  - beginning-of-buffer with an Argument
    - What happens in a large buffer
    - What happens in a small buffer
  - The Complete beginning-of-buffer
- Review
- optional Argument Exercise
Narrowing and Widening
- The save-restriction Special Form
- what-line
- Exercise with Narrowing
car, cdr, cons: Fundamental Functions
- car and cdr
- cons
  - Find the Length of a List: length
- nthcdr
- nth
- setcar
- setcdr
- Exercise
Cutting and Storing Text
- zap-to-char
  - The interactive Expression
  - The Body of zap-to-char
  - The search-forward Function
  - The progn Special Form
  - Summing up zap-to-char
- kill-region
  - condition-case
  - Lisp macro
- copy-region-as-kill
  - The Body of copy-region-as-kill
    - The kill-append function
    - The kill-new function
- Digression into C
- Initializing a Variable with defvar
  - defvar and an asterisk
- Review
- Searching Exercises
How Lists are Implemented
- Symbols as a Chest of Drawers
- Exercise
Yanking Text Back
- Kill Ring Overview
- The kill-ring-yank-pointer Variable
- Exercises with yank and nthcdr
Loops and Recursion
- while
  - A while Loop and a List
  - An Example: print-elements-of-list
  - A Loop with an Incrementing Counter
    - Example with incrementing counter
    - The parts of the function definition
    - Putting the function definition together
  - Loop with a Decrementing Counter
    - Example with decrementing counter
    - The parts of the function definition
    - Putting the function definition together
- Save your time: dolist and dotimes
  - The dolist Macro
  - The dotimes Macro
- Recursion
  - Building Robots: Extending the Metaphor
  - The Parts of a Recursive Definition
  - Recursion with a List
  - Recursion in Place of a Counter
    - An argument of 3 or 4
  - Recursion Example Using cond
  - Recursive Patterns
    - Recursive Pattern: every
    - Recursive Pattern: accumulate
    - Recursive Pattern: keep
  - Recursion without Deferments
  - No Deferment Solution
- Looping Exercise
Regular Expression Searches
- The Regular Expression for sentence-end
- The re-search-forward Function
- forward-sentence
  - The while loops
  - The regular expression search
- forward-paragraph: a Goldmine of Functions
  - The let* expression
  - The forward motion while loop
- Create Your Own TAGS File
- Review
- Exercises with re-search-forward
Counting via Repetition and Regexps
- The count-words-example Function
  - The Whitespace Bug in count-words-example
- Count Words Recursively
- Exercise: Counting Punctuation
Counting Words in a defun
- What to Count?
- What Constitutes a Word or Symbol?
- The count-words-in-defun Function
- Count Several defuns Within a File
- Find a File
- lengths-list-file in Detail
- Count Words in defuns in Different Files
  - The append Function
- Recursively Count Words in Different Files
- Prepare the Data for Display in a Graph
  - Sorting Lists
  - Making a List of Files
  - Counting function definitions
Readying a Graph
- The graph-body-print Function
- The recursive-graph-body-print Function
- Need for Printed Axes
- Exercise
Your .emacs File
- Site-wide Initialization Files
- Specifying Variables using defcustom
- Beginning a .emacs File
- Text and Auto Fill Mode
- Mail Aliases
- Indent Tabs Mode
- Some Keybindings
- Keymaps
- Loading Files
- Autoloading
- A Simple Extension: line-to-top-of-window
- X11 Colors
- Miscellaneous Settings for a .emacs File
- A Modified Mode Line
Debugging
- debug
- debug-on-entry
- debug-on-quit and (debug)
- The edebug Source Level Debugger
- Debugging Exercises
Conclusion
The the-the Function
Handling the Kill Ring
- The current-kill Function
- yank
- yank-pop
- The ring.el File
A Graph with Labeled Axes
- The print-graph Varlist
- The print-Y-axis Function
  - Side Trip: Compute a Remainder
  - Construct a Y Axis Element
  - Create a Y Axis Column
  - The Not Quite Final Version of print-Y-axis
- The print-X-axis Function
  - X Axis Tic Marks
- Printing the Whole Graph
  - Testing print-graph
  - Graphing Numbers of Words and Symbols
  - A lambda Expression: Useful Anonymity
  - The mapcar Function
  - Another Bug ...{} Most Insidious
  - The Printed Graph
Free Software and Free Manuals
GNU Free Documentation License
Index