# Reports:Tasks not implemented in Common Lisp

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**Common Lisp**is a language you like, or are interested in, please inform your fellow members of the Common Lisp community; this page can't be emptied without your and their participation.

## Contents

## Not implemented[edit]

These are currently not implemented in Common Lisp. Please implement some if you can. If any tasks are not possible or too complex in Common Lisp, they should not be on this list. To mark a task as such, add **{{omit from|Common Lisp}}**, preserving the capitalization of the language, to that task. It will appear below under the "Not Considered" section.

### A

### B

### C

- Canny edge detector
- Carmichael 3 strong pseudoprimes
- Cartesian product of two or more lists
- Catalan numbers/Pascal's triangle
- Catmull–Clark subdivision surface
- Chat server
- Check Machin-like formulas
- Checkpoint synchronization
- Circles of given radius through two points
- Colour bars/Display
- Colour pinstripe/Printer
- Combinations with repetitions
- Commatizing numbers
- Compare sorting algorithms' performance
- Compiler/AST interpreter
- Compiler/code generator
- Compiler/syntax analyzer
- Compiler/virtual machine interpreter
- Create a file on magnetic tape
- Create an object at a given address

### D

- Date manipulation
- Death Star
- Deconvolution/2D+
- Department Numbers
- Determine if only one instance is running
- Dinesman's multiple-dwelling problem
- Discordian date
- Distributed programming
- Doubly-linked list/Traversal
- Draw a clock
- Draw a cuboid
- Draw a rotating cube
- Draw a sphere
- Dutch national flag problem

### E

### F

### G

### H

### K

### M

- MAC Vendor Lookup
- Mad Libs
- Magic squares of doubly even order
- Magic squares of singly even order
- Main step of GOST 28147-89
- Matrix arithmetic
- Maze solving
- Median filter
- Memory layout of a data structure
- Metered concurrency
- Morse code
- Mouse position
- Multiplicative order
- Multisplit
- Munchausen numbers
- Munching squares

### P

- Paraffins
- Parametrized SQL statement
- Parse an IP Address
- Partition an integer X into N primes
- Pascal's triangle/Puzzle
- Pathological floating point problems
- Penney's game
- Pentagram
- Percolation/Bond percolation
- Percolation/Mean cluster density
- Percolation/Mean run density
- Percolation/Site percolation
- Permutations/Derangements
- Permutations/Rank of a permutation
- Pinstripe/Display
- Pinstripe/Printer
- Play recorded sounds
- Plot coordinate pairs
- Poker hand analyser
- Polyspiral
- Primes - allocate descendants to their ancestors
- Primorial numbers
- Problem of Apollonius
- Pythagoras tree
- Pythagorean quadruples

### R

- Ramer-Douglas-Peucker line simplification
- Ranking methods
- Reflection/Get source
- Reflection/List methods
- Reflection/List properties
- Rendezvous
- Resistor mesh
- Retrieve and search chat history
- Rock-paper-scissors
- Rosetta Code/Count examples
- Rosetta Code/Find bare lang tags
- Rosetta Code/Find unimplemented tasks
- Rosetta Code/Fix code tags
- Rosetta Code/Rank languages by popularity

### S

- SOAP
- SQL-based authentication
- Safe addition
- Sailors, coconuts and a monkey problem
- Same Fringe
- Scope/Function names and labels
- Secure temporary file
- Send email
- Set puzzle
- Shoelace formula for polygonal area
- Sierpinski pentagon
- Sierpinski triangle/Graphical
- Simulate input/Keyboard
- Smith numbers
- Sokoban
- Solve a Hidato puzzle
- Solve a Holy Knight's tour
- Solve a Hopido puzzle
- Solve a Numbrix puzzle
- Solve the no connection puzzle
- Sort three variables
- Sorting algorithms/Radix sort
- Special characters
- Speech synthesis
- Stable marriage problem
- Start from a main routine
- State name puzzle
- Statistics/Basic
- Statistics/Normal distribution
- Stem-and-leaf plot
- Straddling checkerboard
- Stream Merge
- Strip block comments
- Sum and Product Puzzle
- Sum to 100
- Superellipse
- Sutherland-Hodgman polygon clipping

### T

- Table creation/Postal addresses
- Taxicab numbers
- Terminal control/Coloured text
- Terminal control/Cursor movement
- Terminal control/Cursor positioning
- Terminal control/Dimensions
- Terminal control/Inverse video
- Terminal control/Positional read
- Test a function
- Test integerness
- Text processing/2
- Textonyms
- Topic variable
- Topswops
- Total circles area
- Truncate a file
- Truth table

### U

### V

### W

### Draft tasks without implementation[edit]

These tasks as drafts, meaning they largely need more work to turn them into full tasks. Perhaps you can help by trying to implement them in Common Lisp (after all, one of the key requirements for a task being non-draft is multiple implementations, preferably in widely different languages) but be aware that this may be difficult because of lack of definition of the task itself.

### A

- A* search algorithm
- ASCII art diagram converter
- Abbreviations, automatic
- Abbreviations, easy
- Abbreviations, simple
- Addition-chain exponentiation
- Addition chains
- Arithmetic coding/As a generalized change of radix
- Assertions in design by contract
- AudioAlarm
- Audio Overlap Loop
- Audio frequency generator

### B

### C

- Card shuffles
- Chebyshev coefficients
- Chess player
- Chess player/Move generation
- Chess player/Program options and user interface
- Chess player/Search and evaluation
- Cipolla's algorithm
- Code segment unload
- Color wheel
- Combinations with repetitions/Square Digit Chain
- Continued fraction/Arithmetic/G(matrix NG, Contined Fraction N)
- Continued fraction/Arithmetic/G(matrix NG, Contined Fraction N1, Contined Fraction N2)
- Convex hull
- Create an object/Native demonstration
- Currency
- Cycle detection

### D

### E

### F

- Faulhaber's formula
- Faulhaber's triangle
- Fibonacci heap
- File extension is in extensions list
- File size distribution
- Find URI in text
- Find duplicate files
- Find first and last set bit of a long integer
- Finite state machine
- Four is magic
- Four is the number of letters in the ...
- Free polyominoes enumeration
- French Republican calendar
- Functional coverage tree

### G

### H

### I

- I.Q. Puzzle
- IPC via named pipe
- IRC gateway
- Idiomatically determine all the characters that can be used for symbols
- Idiomatically determine all the lowercase and uppercase letters
- Imaginary base numbers
- Implicit type conversion
- Index finite lists of positive integers
- Input/Output for Lines of Text
- Input/Output for Pairs of Numbers
- Integer roots

### L

### M

### O

### P

### R

- Railway circuit
- Ramsey's theorem
- Readline interface
- Recursive descent parser generator
- Reflection/List methods
- Remote agent/Agent interface
- Remote agent/Agent logic
- Remote agent/Simulation
- Reverse the gender of a string
- Robots
- Rosetta Code/List authors of task descriptions
- Rosetta Code/Run examples
- Rosetta Code/Tasks sorted by average lines of code
- Rosetta Code/Tasks without examples
- Run as a daemon or service

### S

- Sattolo cycle
- Selective File Copy
- Self-hosting compiler
- Separate the house number from the street name
- Sequence of primorial primes
- Shortest common supersequence
- Simulated annealing
- Singly-linked list/Element removal
- Snake
- Snake And Ladder
- Solve a Rubik's Cube
- Solving coin problems
- Sorting Algorithms/Circle Sort
- Sorting algorithms/Cycle sort
- Sorting algorithms/Patience sort
- Sorting algorithms/Tree sort on a linked list
- Spelling of ordinal numbers
- Starting a web browser
- Subset sum problem
- Substitution Cipher
- Suffix tree
- Superpermutation minimisation

### T

- Table creation
- Tamagotchi emulator
- Tarjan
- Terminal control/Restricted width positional input/No wrapping
- Terminal control/Restricted width positional input/With wrapping
- Tetris
- Text to HTML
- Time-based One-time Password Algorithm
- Tonelli-Shanks algorithm
- Topological sort/Extracted top item
- Transportation problem
- Two Sum
- Type detection

### U

### W

## Requiring Attention[edit]

### Examples[edit]

These tasks have implementations in Common Lisp, but somebody, somewhere, decided that the example implementation was faulty or in some other way requiring attention. If you're familiar with the task and language, please consider reviewing/correcting the example and removing the notice.

### Other pages[edit]

These are other pages related to Common Lisp which require attention; with your knowledge and assistance, we can improve the quality of the site's content.

### No pages found.

## Not Considered[edit]

These tasks are not generally counted toward "unimplemented", as somebody, somewhere, decided that Common Lisp was inappropriate for these tasks, or implementations of them would be unenlightening. Feel free to try your hand at them anyway.

### No pages found.

## End of List[edit]

Again, feel free to try your hand at any of the tasks listed on this page.