# Reports:Tasks not implemented in Common Lisp

**Awareness**

If

**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.

### 2

### A

- ASCII art diagram converter
- Abbreviations, easy
- Abbreviations, simple
- Abelian sandpile model
- Abelian sandpile model/Identity
- Active Directory/Connect
- Active Directory/Search for a user
- Active object
- Approximate Equality
- Arena storage pool
- Associative array/Merging
- Attractive numbers
- Average loop length

### B

- Bioinformatics/base count
- Biorhythms
- Bitcoin/address validation
- Bitcoin/public point to address
- Bitmap/Bézier curves/Cubic
- Bitmap/Bézier curves/Quadratic
- Bitmap/Flood fill
- Bitmap/PPM conversion through a pipe
- Bitmap/Read an image through a pipe
- Box the compass
- Brazilian numbers
- Burrows–Wheeler transform

### C

- Canny edge detector
- Canonicalize CIDR
- Cantor set
- Carmichael 3 strong pseudoprimes
- Catmull–Clark subdivision surface
- Chaocipher
- Check Machin-like formulas
- Checkpoint synchronization
- Chernick's Carmichael numbers
- Chowla numbers
- Church Numerals
- Circles of given radius through two points
- Circular primes
- Color wheel
- Colour pinstripe/Printer
- Commatizing numbers
- Compare sorting algorithms' performance
- Compiler/AST interpreter
- Compiler/code generator
- Compiler/syntax analyzer
- Compiler/virtual machine interpreter
- Convex hull
- Copy stdin to stdout
- Create a file on magnetic tape
- Create an object at a given address
- Currency
- Cyclotomic Polynomial

### D

- Damm algorithm
- Date manipulation
- De Bruijn sequences
- Death Star
- Deconvolution/2D+
- Deming's Funnel
- Department Numbers
- Determine if a string is collapsible
- Determine if a string is squeezable
- Determine if only one instance is running
- Determine if two triangles overlap
- Dice game probabilities
- Discordian date
- Display a linear combination
- Display an outline as a nested table
- Distributed programming
- Diversity prediction theorem
- Doubly-linked list/Traversal
- Draw a clock
- Draw a cuboid
- Draw a pixel
- Draw a rotating cube
- Dutch national flag problem

### E

- EKG sequence convergence
- Eban numbers
- Eertree
- Elementary cellular automaton/Infinite length
- Elementary cellular automaton/Random Number Generator
- Elliptic curve arithmetic
- Enforced immutability
- Entropy/Narcissist
- Events
- Executable library
- Execute SNUSP
- Extensible prime generator
- Extreme floating point values

### F

- Faces from a mesh
- Factorial base numbers indexing permutations of a collection
- Factorions
- Fairshare between two and more
- Faulhaber's formula
- Faulhaber's triangle
- Feigenbaum constant calculation
- Fermat numbers
- Fibonacci word/fractal
- File extension is in extensions list
- File size distribution
- Find common directory path
- Find duplicate files
- Find largest left truncatable prime in a given base
- Find the intersection of a line with a plane
- Find the intersection of two lines
- First class environments
- First perfect square in base N with N unique digits
- First power of 2 that has leading decimal digits of 12
- Fivenum
- Fixed length records
- Flipping bits game
- Flow-control structures
- Floyd-Warshall algorithm
- Four is the number of letters in the ...
- Fraction reduction
- Functional coverage tree
- Fusc sequence

### G

### H

### I

- ISBN13 check digit
- Idiomatically determine all the characters that can be used for symbols
- Idiomatically determine all the lowercase and uppercase letters
- Imaginary base numbers
- Increasing gaps between consecutive Niven numbers
- Index finite lists of positive integers
- Integer overflow
- Intersecting Number Wheels
- Isqrt (integer square root) of X

### K

### L

### M

- Mad Libs
- Magic 8-Ball
- Magic squares of doubly even order
- Magic squares of singly even order
- Main step of GOST 28147-89
- Mastermind
- Matrix chain multiplication
- Mayan numerals
- Maze solving
- McNuggets Problem
- Median filter
- Memory layout of a data structure
- Mertens function
- Metallic ratios
- Metered concurrency
- Mian-Chowla sequence
- Mind boggling card trick
- Minimal steps down to 1
- Modular arithmetic
- Monads/List monad
- Monads/Maybe monad
- Monads/Writer monad
- Morse code
- Multi-dimensional array
- Multiplicative order
- Multisplit
- Munching squares
- Mutex

### N

### P

- P-value correction
- Palindrome dates
- Palindromic gapful numbers
- Paraffins
- Parametrized SQL statement
- Parse an IP Address
- Partition an integer X into N primes
- Pascal's triangle/Puzzle
- Pathological floating point problems
- Peaceful chess queen armies
- Peano curve
- Pell's equation
- Penney's game
- Pentagram
- Percolation/Bond percolation
- Percolation/Mean cluster density
- Percolation/Mean run density
- Percolation/Site percolation
- Perfect totient numbers
- Permutations/Derangements
- Permutations/Rank of a permutation
- Pierpont primes
- Pinstripe/Display
- Pinstripe/Printer
- Play recorded sounds
- Playfair cipher
- Plot coordinate pairs
- Poker hand analyser
- Polyspiral
- Primality by Wilson's theorem
- Prime conspiracy
- Primes - allocate descendants to their ancestors
- Problem of Apollonius
- Pseudo-random numbers/Combined recursive generator MRG32k3a
- Pseudo-random numbers/PCG32
- Pseudo-random numbers/Xorshift star
- Pythagoras tree
- Pythagorean quadruples

### R

- Ramanujan's constant
- Ramer-Douglas-Peucker line simplification
- Range consolidation
- Ranking methods
- Rare numbers
- Recaman's sequence
- 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
- Safe primes and unsafe primes
- Sailors, coconuts and a monkey problem
- Same Fringe
- Scope/Function names and labels
- Secure temporary file
- Self numbers
- Send email
- Sequence: nth number with exactly n divisors
- Sequence: smallest number greater than previous term with exactly n divisors
- Sequence: smallest number with exactly n divisors
- Sequence of primorial primes
- Set puzzle
- Sexy primes
- Shoelace formula for polygonal area
- Shortest common supersequence
- Sierpinski pentagon
- Sierpinski triangle/Graphical
- Simulate input/Keyboard
- Smarandache prime-digital sequence
- 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/Circle Sort
- Sorting algorithms/Cocktail sort with shifting bounds
- Sorting algorithms/Patience sort
- Sorting algorithms/Radix sort
- Special characters
- Speech synthesis
- Spinning rod animation/Text
- Square-free integers
- Square but not cube
- Stable marriage problem
- Start from a main routine
- State name puzzle
- Statistics/Basic
- Statistics/Normal distribution
- Stem-and-leaf plot
- Stirling numbers of the first kind
- Stirling numbers of the second kind
- Straddling checkerboard
- Stream Merge
- Strip block comments
- Strong and weak primes
- Substitution Cipher
- Successive prime differences
- Suffixation of decimal numbers
- Sunflower fractal
- Super-d numbers
- Superellipse
- Superpermutation minimisation
- Sutherland-Hodgman polygon clipping

### T

### U

### V

### W

### Draft tasks without implementation[edit]

These tasks are 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

### B

### C

- CLI-based maze-game
- Card shuffles
- Chebyshev coefficients
- Checksumcolor
- Chemical Calculator
- Chess player
- Cipolla's algorithm
- Code segment unload
- Combinations with repetitions/Square Digit Chain
- Compiler/Verifying Syntax
- Continued fraction/Arithmetic/G(matrix NG, Contined Fraction N)
- Continued fraction/Arithmetic/G(matrix NG, Contined Fraction N1, Contined Fraction N2)
- Create DWM statusbar
- Create an object/Native demonstration
- Curve that touches three points
- Cycle detection

### D

### E

### F

### G

### H

### I

### L

- Latin Squares in reduced form/Randomizing using Jacobson and Matthews’ Technique
- Launch rocket with countdown and acceleration in stdout
- Length of an arc between two angles
- Line circle intersection
- Linux CPU utilization
- Logistic Curve Fitting in Epidemiology
- Longest common prefix
- Longest common suffix
- Longest palindromic substrings

### M

### N

### P

- Parse EBNF
- Parse command-line arguments
- Particle Swarm Optimization
- Penrose tiling
- Pentomino tiling
- Perceptron
- Permutations with repetitions
- Permutations with some identical elements
- Pisano period
- Polynomial synthetic division
- Powerful numbers
- Print debugging statement
- Print itself
- Process SMIL directives in XML data
- Proof
- Pseudo-random numbers/Splitmix64
- Pseudorandom Number Generator Image

### R

- Railway circuit
- Ramsey's theorem
- Random Latin Squares
- Range modifications
- Raster bars
- Readline interface
- Recursive descent parser generator
- Remote agent/Agent interface
- Remote agent/Agent logic
- Remote agent/Simulation
- Remove vowels from a string
- Resistance Calculator
- Resistance Network Calculator
- Reverse the gender of a string
- Robots
- Rosetta Code/List authors of task descriptions
- Rosetta Code/Rank languages by number of users
- Rosetta Code/Run examples
- Rosetta Code/Tasks without examples
- Run as a daemon or service

### S

- Safe mode
- Sattolo cycle
- Selective File Copy
- Self-hosting compiler
- Separate the house number from the street name
- Sierpinski arrowhead curve
- Sierpinski curve
- Sierpinski square curve
- Simulated annealing
- Sine wave
- Singly-linked list/Element removal
- Snake
- Snake And Ladder
- Solve a Rubik's Cube
- Solve triangle solitare puzzle
- Solving coin problems
- Sort an outline at every level
- Sorting algorithms/Cycle sort
- Sorting algorithms/Tree sort on a linked list
- Spoof game
- Square Root by Hand
- Starting a web browser
- Strassen's algorithm
- Subset sum problem
- Suffix tree
- Sum data type

### T

### 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.