Emacs Lisp

Emacs Lisp (often abbreviated to elisp) is the Lisp implementation used by the Emacs text editor. It doesn't provide all features of Common Lisp (e.g. its optional arguments always default to nil), but it contains special types which are specific for the use in the editor, like buffers (which is where you actually edit the text), windows, events etc.

Lisp expressions can be executed directly from within Emacs editor buffers, or loaded from files which optionally can be compiled into bytecode.

Emacs configuration files actually are Emacs Lisp source files.

Emacs Lisp can be used as a general programming language with the emacs "-batch" or "--script" command line arguments. http://www.emacswiki.org/emacs/BatchMode

Tasks

• 100 doors
• A+B
• Ackermann function
• Arbitrary-precision integers (included)
• Arithmetic evaluation
• Array concatenation
• Array length
• Assertions
• Associative array/Creation
• Averages/Arithmetic mean
• Averages/Mode
• Averages/Root mean square
• Binary search
• Boolean values
• Character codes
• Check that file exists
• Closures/Value capture
• Combinations
• Command-line arguments
• Comments
• Copy a string
• Count in octal
• Create a file
• Cumulative standard deviation
• Date format
• Delete a file
• Detect division by zero
• Documentation
• Dot product
• Dragon curve
• Dynamic variable names
• Empty string
• Entropy
• Entropy/Narcissist
• Environment variables
• Ethiopian multiplication
• Even or odd
• Execute a system command
• Extract file extension
• Factorial
• Fibonacci sequence
• Find limit of recursion
• FizzBuzz
• Flatten a list
• Forest fire
• Formatted numeric output
• Function composition
• Function definition
• Generator/Exponential
• Generic swap
• Greatest element of a list
• Guess the number
• Guess the number/With feedback
• HTTP
• Hello world!
• Hello world/Newline omission
• Hello world/Standard error
• Hello world/Text
• Horner's rule for polynomial evaluation
• Hostname
• Include a file
• Increment a numerical string
• Integer comparison
• Integer sequence
• Interactive programming
• Josephus problem
• Kernighans large earthquake problem
• Knapsack problem/0-1
• Leap year
• Literals/Integer
• Literals/String
• Loops/Do-while
• Loops/Foreach
• Loops/Infinite
• Loops/While
• Luhn test of credit card numbers
• MD4
• MD5
• Map range
• Matrix transposition
• Maze generation
• Maze solving
• Modular exponentiation
• Modulinos
• Monty Hall problem
• Multiline shebang
• Multiple regression
• Pattern matching
• Phrase reversals
• Pick random element
• Polynomial regression
• Primality by trial division
• Program name
• Program termination
• Range extraction
• Read entire file
• Regular expressions
• Rename a file
• Repeat a string
• Reverse a string
• Reverse words in a string
• Roman numerals/Decode
• Roman numerals/Encode
• Run-length encoding
• SHA-256
• Secure temporary file
• Send email
• Shell one-liner
• Sieve of Eratosthenes
• Sleep
• Sockets
• Sorting algorithms/Insertion sort
• Spinning rod animation/Text
• String append
• String concatenation
• String length
• String matching
• String prepend
• Strip whitespace from a string/Top and tail
• Substring/Top and tail
• Sum and product of an array
• Sum digits of an integer
• Sum multiples of 3 and 5
• Sum of a series
• Sum of squares
• System time
• Terminal control/Preserve screen
• Terminal control/Ringing the terminal bell
• Unicode variable names
• Variadic function
• Walk a directory/Non-recursively
• Walk a directory/Recursively
• Window creation