# Reports:Tasks not implemented in Seed7

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## Contents

## Not implemented[edit]

These are currently not implemented in Seed7. Please implement some if you can. If any tasks are not possible or too complex in Seed7, they should not be on this list. To mark a task as such, add **{{omit from|Seed7}}**, preserving the capitalization of the language, to that task. It will appear below under the "Not Considered" section.

### A

- ASCII art diagram converter
- AVL tree
- Abbreviations, automatic
- Abbreviations, easy
- Abbreviations, simple
- Abelian sandpile model
- Abelian sandpile model/Identity
- Abundant odd numbers
- Accumulator factory
- Active Directory/Connect
- Active Directory/Search for a user
- Active object
- Add a variable to a class instance at runtime
- Address of a variable
- Aliquot sequence classifications
- Amicable pairs
- Anagrams/Deranged anagrams
- Angles (geometric), normalization and conversion
- Animate a pendulum
- Animation
- Append a record to the end of a text file
- Apply a callback to an array
- Apply a digital filter (direct form II transposed)
- Approximate equality
- Arena storage pool
- Arithmetic-geometric mean/Calculate Pi
- Arithmetic evaluation
- Assertions
- Associative array/Merging
- Atomic updates
- Attractive numbers
- Averages/Mean time of day
- Averages/Simple moving average

### B

- Balanced ternary
- Barnsley fern
- Bell numbers
- Benford's law
- Bin given limits
- Bioinformatics/Sequence mutation
- Bioinformatics/base count
- Biorhythms
- Bitmap/Bresenham's line algorithm
- Bitmap/Bézier curves/Cubic
- Bitmap/Bézier curves/Quadratic
- Bitmap/Flood fill
- Bitmap/Histogram
- Bitmap/Midpoint circle algorithm
- Bitmap/PPM conversion through a pipe
- Bitmap/Read an image through a pipe
- Brazilian numbers
- Break OO privacy
- Bulls and cows/Player
- Burrows–Wheeler transform

### C

- CUSIP
- Calkin-Wilf sequence
- Call a foreign-language function
- Call a function in a shared library
- Call an object method
- Canny edge detector
- Canonicalize CIDR
- Cantor set
- Cartesian product of two or more lists
- Catamorphism
- Catmull–Clark subdivision surface
- Chaocipher
- Chaos game
- Chat server
- Check input device is a terminal
- Check output device is a terminal
- Checkpoint synchronization
- Chernick's Carmichael numbers
- Cheryl's birthday
- Chowla numbers
- Church numerals
- Circular primes
- Cistercian numerals
- Classes
- Closures/Value capture
- Color of a screen pixel
- Color quantization
- Color wheel
- Colour bars/Display
- Colour pinstripe/Display
- Colour pinstripe/Printer
- Combinations and permutations
- Combinations with repetitions
- Commatizing numbers
- Compare sorting algorithms' performance
- Compiler/AST interpreter
- Compiler/code generator
- Compiler/lexical analyzer
- Compiler/syntax analyzer
- Compiler/virtual machine interpreter
- Concurrent computing
- Conjugate transpose
- Constrained genericity
- Constrained random points on a circle
- Continued fraction
- Continued fraction/Arithmetic/Construct from rational number
- Convert seconds to compound duration
- Convex hull
- Conway's Game of Life
- Cramer's rule
- Create an object at a given address
- Cuban primes
- Cumulative standard deviation
- Currency
- Currying
- Cut a rectangle
- Cyclotomic polynomial

### D

- Damm algorithm
- De Bruijn sequences
- Death Star
- Deconvolution/1D
- Deconvolution/2D+
- Deepcopy
- Define a primitive data type
- Delegates
- Deming's Funnel
- Department numbers
- Determinant and permanent
- Determine if a string has all the same characters
- Determine if a string has all unique characters
- 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
- Digital root/Multiplicative digital root
- Dijkstra's algorithm
- Dinesman's multiple-dwelling problem
- Dining philosophers
- Display a linear combination
- Display an outline as a nested table
- Distributed programming
- Diversity prediction theorem
- Documentation
- Doubly-linked list/Definition
- Doubly-linked list/Element definition
- Doubly-linked list/Element insertion
- Doubly-linked list/Traversal
- Draw a cuboid
- Draw a pixel
- Draw a rotating cube
- Draw a sphere
- Dutch national flag problem
- Dynamic variable names

### E

- EKG sequence convergence
- Eban numbers
- Eertree
- Egyptian division
- Egyptian fractions
- Element-wise operations
- Elementary cellular automaton
- Elementary cellular automaton/Infinite length
- Elementary cellular automaton/Random Number Generator
- Elliptic Curve Digital Signature Algorithm
- Elliptic curve arithmetic
- Emirp primes
- Entropy/Narcissist
- Euler's identity
- Euler method
- Events
- Executable library
- Execute a Markov algorithm
- Exponentiation with infix operators in (or operating on) the base

### F

- Faces from a mesh
- Factorial base numbers indexing permutations of a collection
- Factorions
- Fairshare between two and more
- Farey sequence
- Fast Fourier transform
- Faulhaber's formula
- Faulhaber's triangle
- Feigenbaum constant calculation
- Fermat numbers
- Fibonacci word/fractal
- File extension is in extensions list
- File size distribution
- Find duplicate files
- Find largest left truncatable prime in a given base
- Find limit of recursion
- Find palindromic numbers in both binary and ternary bases
- Find the intersection of a line with a plane
- Find the intersection of two lines
- First-class functions
- First-class functions/Use numbers analogously
- 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
- Flatten a list
- Flipping bits game
- Flow-control structures
- Floyd-Warshall algorithm
- Forest fire
- Fork
- Formal power series
- Four bit adder
- Four is magic
- Four is the number of letters in the ...
- Fraction reduction
- French Republican calendar
- Function composition
- Function frequency
- Function prototype
- Functional coverage tree
- Fusc sequence

### G

- GUI/Maximum window dimensions
- GUI component interaction
- GUI enabling/disabling of controls
- Galton box animation
- Gapful numbers
- Gauss-Jordan matrix inversion
- Gaussian elimination
- General FizzBuzz
- Generate random chess position
- Generator/Exponential
- Get system command output
- Go Fish
- Graph colouring
- Grayscale image

### H

- HTTPS/Authenticated
- HTTPS/Client-authenticated
- Handle a signal
- Hash join
- Hello world/Newbie
- Here document
- Heronian triangles
- Higher-order functions
- History variables
- Hofstadter-Conway $10,000 sequence
- Hofstadter Figure-Figure sequences
- Honeycombs
- Hough transform
- Huffman coding
- Humble numbers
- Hunt the Wumpus

### I

- ISBN13 check digit
- Idiomatically determine all the characters that can be used for symbols
- Idiomatically determine all the lowercase and uppercase letters
- Image convolution
- Image noise
- Imaginary base numbers
- Increasing gaps between consecutive Niven numbers
- Index finite lists of positive integers
- Inheritance/Multiple
- Interactive programming
- Intersecting number wheels
- Introspection
- Inverted index
- Inverted syntax
- Iterated digits squaring

### J

### K

### L

- LU decomposition
- Lah numbers
- Largest int from concatenated ints
- Largest number divisible by its digits
- Latin Squares in reduced form
- Law of cosines - triples
- Levenshtein distance/Alignment
- List comprehensions
- List rooted trees
- Long literals, with continuations
- Long primes
- Long year
- Longest common substring
- Longest increasing subsequence
- Longest string challenge
- Loop over multiple arrays simultaneously
- Loops/Continue
- Loops/With multiple ranges
- Lucky and even lucky numbers
- Lychrel numbers

### M

- MAC Vendor Lookup
- Machine code
- Magic 8-ball
- Magic squares of doubly even order
- Magic squares of singly even order
- Main step of GOST 28147-89
- Man or boy test
- Mastermind
- Matrix chain multiplication
- Matrix digital rain
- Maximum triangle path sum
- Mayan numerals
- Maze generation
- Maze solving
- McNuggets problem
- Median filter
- Memory allocation
- Memory layout of a data structure
- Merge and aggregate datasets
- Mertens function
- Metallic ratios
- Metaprogramming
- Metered concurrency
- Metronome
- Mian-Chowla sequence
- Mind boggling card trick
- Minesweeper game
- Minimal steps down to 1
- Minkowski question-mark function
- Modified random distribution
- Modular arithmetic
- Monads/List monad
- Monads/Maybe monad
- Monads/Writer monad
- Morse code
- Move-to-front algorithm
- Multi-dimensional array
- Multiple regression
- Multisplit
- Munchausen numbers
- Munching squares
- Musical scale
- Mutex

### N

- N-smooth numbers
- Named parameters
- Naming conventions
- Narcissist
- Narcissistic decimal number
- Natural sorting
- Nested templated data
- Next highest int from digits
- Nim game
- Nimber arithmetic
- Non-transitive dice
- Nonoblock
- Nonogram solver
- Null object
- Numeric error propagation
- Numerical and alphabetical suffixes
- Numerical integration
- Numerical integration/Gauss-Legendre Quadrature

### O

### P

- P-Adic numbers, basic
- P-Adic square roots
- P-value correction
- Padovan n-step number sequences
- Padovan sequence
- Palindrome dates
- Palindromic gapful numbers
- Pancake numbers
- Parallel brute force
- Parallel calculations
- Parse an IP Address
- Parsing/RPN calculator algorithm
- Parsing/RPN to infix conversion
- Parsing/Shunting-yard algorithm
- Partial function application
- Partition an integer x into n primes
- Partition function P
- Pascal's triangle/Puzzle
- Pascal matrix generation
- Pathological floating point problems
- Pattern matching
- Peaceful chess queen armies
- Peano curve
- Pell's equation
- Penney's game
- Pentagram
- Percentage difference between images
- Percolation/Bond percolation
- Percolation/Mean cluster density
- Percolation/Mean run density
- Percolation/Site percolation
- Perfect shuffle
- Perfect totient numbers
- Perlin noise
- Permutations/Derangements
- Permutations/Rank of a permutation
- Permutations by swapping
- Pierpont primes
- Pig the dice game
- Pig the dice game/Player
- Pinstripe/Display
- Pinstripe/Printer
- Plasma effect
- Play recorded sounds
- Playfair cipher
- Playing cards
- Plot coordinate pairs
- Pointers and references
- Polymorphic copy
- Polynomial long division
- Polynomial regression
- Polyspiral
- Pragmatic directives
- Primality by Wilson's theorem
- Primes - allocate descendants to their ancestors
- Primorial numbers
- Priority queue
- Problem of Apollonius
- Pseudo-random numbers/Combined recursive generator MRG32k3a
- Pseudo-random numbers/PCG32
- Pseudo-random numbers/Xorshift star
- Pythagoras tree
- Pythagorean quadruples

### R

- RCRPG
- Ramanujan's constant
- Ramer-Douglas-Peucker line simplification
- Random Latin squares
- Random number generator (device)
- Random sentence from book
- Range consolidation
- Ranking methods
- Rare numbers
- Rate counter
- Ray-casting algorithm
- Recaman's sequence
- Record sound
- Reflection/Get source
- Reflection/List methods
- Reflection/List properties
- Regular expressions
- Rendezvous
- Repeat
- Resistor mesh
- Respond to an unknown method call
- Retrieve and search chat history
- Roots of a function
- 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 number of users
- Runge-Kutta method
- Runtime evaluation
- Runtime evaluation/In an environment

### S

- S-expressions
- SHA-256 Merkle tree
- SOAP
- SQL-based authentication
- Safe addition
- Safe primes and unsafe primes
- Sailors, coconuts and a monkey problem
- Same fringe
- Scope/Function names and labels
- Scope modifiers
- Search a list
- Search a list of records
- Secure temporary file
- Self numbers
- Send an unknown method call
- 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 primes by trial division
- Sequence of primorial primes
- Set consolidation
- Set of real numbers
- Set puzzle
- Seven-sided dice from five-sided dice
- Sexy primes
- Shell one-liner
- Shoelace formula for polygonal area
- Shortest common supersequence
- Sierpinski pentagon
- Simple database
- Simple windowed application
- Simulate input/Keyboard
- Simulate input/Mouse
- Singleton
- Singly-linked list/Element definition
- Singly-linked list/Element insertion
- Singly-linked list/Traversal
- Smarandache prime-digital sequence
- Smith numbers
- Sokoban
- Solve a Holy Knight's tour
- Solve a Hopido puzzle
- Solve a Numbrix puzzle
- Solve the no connection puzzle
- Sort a list of object identifiers
- Sort an outline at every level
- Sort disjoint sublist
- Sort numbers lexicographically
- Sort stability
- Sort using a custom comparator
- Sorting Algorithms/Circle Sort
- Sorting algorithms/Bogosort
- Sorting algorithms/Cocktail sort with shifting bounds
- Sorting algorithms/Comb sort
- Sorting algorithms/Counting sort
- Sorting algorithms/Gnome sort
- Sorting algorithms/Pancake sort
- Sorting algorithms/Patience sort
- Sorting algorithms/Permutation sort
- Sorting algorithms/Radix sort
- Sorting algorithms/Sleep sort
- Sorting algorithms/Stooge sort
- Sorting algorithms/Strand sort
- Soundex
- Special variables
- Speech synthesis
- Spelling of ordinal numbers
- Spinning rod animation/Text
- Split a character string based on change of character
- Square-free integers
- Square Form Factorization
- Square but not cube
- Stack traces
- State name puzzle
- Statistics/Basic
- Statistics/Normal distribution
- Stern-Brocot sequence
- Stirling numbers of the first kind
- Stirling numbers of the second kind
- Straddling checkerboard
- Stream merge
- Strong and weak primes
- Subleq
- Substitution cipher
- Successive prime differences
- Sudoku
- Suffixation of decimal numbers
- Sum and product puzzle
- Sum to 100
- Summarize and say sequence
- Sunflower fractal
- Super-d numbers
- Superellipse
- Superpermutation minimisation
- Sutherland-Hodgman polygon clipping
- Synchronous concurrency

### T

- Table creation/Postal addresses
- Tarjan
- Tau function
- Tau number
- Taxicab numbers
- Teacup rim text
- Terminal control/Coloured text
- Terminal control/Cursor movement
- Terminal control/Hiding the cursor
- Terminal control/Inverse video
- Terminal control/Positional read
- Terminal control/Preserve screen
- Test a function
- Test integerness
- Text processing/1
- Text processing/2
- Textonyms
- The ISAAC Cipher
- The Name Game
- Thiele's interpolation formula
- Thue-Morse
- Tic-tac-toe
- Tokenize a string with escaping
- Tonelli-Shanks algorithm
- Top rank per group
- Topic variable
- Topological sort
- Topswops
- Total circles area
- Totient function
- Trabb Pardo–Knuth algorithm
- Tree datastructures
- Tree from nesting levels
- Tree traversal
- Truncatable primes
- Truncate a file
- Truth table
- Twelve statements

### U

### V

- Validate International Securities Identification Number
- Vampire number
- Van Eck sequence
- Variable size/Get
- Variable size/Set
- Variadic function
- Vector
- Verify distribution uniformity/Chi-squared test
- Verify distribution uniformity/Naive
- Video display modes
- Vigenère cipher/Cryptanalysis
- Visualize a tree
- Vogel's approximation method

### 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 Seed7 (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
- ABC words
- Addition-chain exponentiation
- Addition chains
- Additive primes
- Air mass
- Almkvist-Giullera formula for pi
- Alternade words
- Arithmetic coding/As a generalized change of radix
- Aspect oriented programming
- Assertions in design by contract
- Audio alarm
- Audio frequency generator
- Audio overlap loop

### B

### C

- CLI-based maze-game
- Card shuffles
- Change e letters to i in words
- Changeable words
- Chebyshev coefficients
- Checksumcolor
- Chemical calculator
- Chess player
- Cipolla's algorithm
- Code segment unload
- Combinations with repetitions/Square digit chain
- Common list elements
- Common sorted list
- Compiler/Verifying syntax
- Consecutive Primes With Ascending Or Descending Differences
- Continued fraction/Arithmetic/G(matrix ng, continued fraction n)
- Continued fraction/Arithmetic/G(matrix ng, continued fraction n1, continued fraction n2)
- Count the coins/0-1
- Cousin primes
- Create an object/Native demonstration
- Cubic Special Primes
- Curve that touches three points
- Cycle detection

### D

### E

### F

- Fibonacci heap
- Fibonacci matrix-exponentiation
- Find URI in text
- Find first missing positive
- Find if a point is within a triangle
- Find prime n for that reversed n is also prime
- Find prime numbers of the form n*n*n+2
- Find words which contains all the vowels
- Find words which contains more than 3 e vowels
- Find words which contains most consonants
- Find words which first and last three letters are equals
- Find words with alternating vowels and consonants
- Finite state machine
- Free polyominoes enumeration
- Frobenius numbers

### G

### 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

- Magnanimous numbers
- Make a backup file
- Markov chain text generator
- Mayan calendar
- Mersenne primes
- Minimum positive multiple in base 10 using only 0 and 1
- Modulinos
- Montgomery reduction
- Morpion solitaire
- Most frequent k chars distance
- Multidimensional Newton-Raphson method
- Multiline shebang
- Möbius function

### N

- N-body problem
- NYSIIS
- Names to numbers
- Native shebang
- Neighbour primes
- Next special primes
- Nice primes
- Numbers divisible by their individual digits, but not by the product of their digits.
- Numbers which binary and ternary digit sum are prime
- Numbers with equal rises and falls
- Numbers with prime digits whose sum is 13
- Numeric separator syntax
- Numerical integration/Adaptive Simpson's method

### O

### P

- Palindromic primes
- Parse EBNF
- Parse command-line arguments
- Particle swarm optimization
- Penrose tiling
- Pentomino tiling
- Perceptron
- Permutations with repetitions
- Permutations with some identical elements
- Piprimes
- Pisano period
- Polynomial synthetic division
- Powerful numbers
- Practical numbers
- Price list behind API
- Prime triplets
- Prime words
- Primes which sum of digits is 25
- Primes with digits in nondecreasing order
- Print debugging statement
- Print itself
- Process SMIL directives in XML data
- Product of divisors
- Proof
- Pseudo-random numbers/Splitmix64
- Pseudorandom number generator image

### R

- Railway circuit
- Ramsey's theorem
- 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/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
- Shift list elements to left by 3
- Show the (decimal) value of a number of 1s appended with a 3, then squared
- Sierpinski arrowhead curve
- Sierpinski curve
- Sierpinski square curve
- Simulated annealing
- Sine wave
- Singly-linked list/Element removal
- Smallest enclosing circle problem
- Smallest numbers
- Smallest power of 6 whose decimal expansion contains n
- Smallest square that begins with n
- Snake
- Snake and Ladder
- Solve a Rubik's Cube
- Solve triangle solitare puzzle
- Solving coin problems
- Sorting algorithms/Cycle sort
- Sorting algorithms/Tree sort on a linked list
- Special Divisors
- Special factorials
- Spoof game
- Square root by hand
- Starting a web browser
- Strange numbers
- Strange plus numbers
- Strange unique prime triplets
- Strassen's algorithm
- Subset sum problem
- Substring primes
- Suffix tree
- Sum data type
- Sum of divisors
- Sum of the digits of n is substring of n
- Summarize primes

### T

- Table creation
- Tamagotchi emulator
- Terminal control/Restricted width positional input/No wrapping
- Terminal control/Restricted width positional input/With wrapping
- Tetris
- Text between
- Text completion
- Text to HTML
- Three word location
- Time-based one-time password algorithm
- Topological sort/Extracted top item
- Transportation problem
- Twin primes
- Two bullet roulette
- Two identical strings
- Two sum
- Type detection

### U

### W

## Requiring Attention[edit]

### Examples[edit]

These tasks have implementations in Seed7, 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 Seed7 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 Seed7 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.