# Reports:Tasks not implemented in REXX

**Awareness**

If

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

## Contents

## Not implemented[edit]

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

### A

### B

### C

- Canny edge detector
- Catmull–Clark subdivision surface
- Chaocipher
- Chat server
- Checkpoint synchronization
- Chernick's Carmichael numbers
- Chinese zodiac
- Church numerals
- Color quantization
- Color wheel
- Colorful numbers
- Colour pinstripe/Display
- Colour pinstripe/Printer
- Compiler/AST interpreter
- Compiler/code generator
- Compiler/lexical analyzer
- Compiler/syntax analyzer
- Compiler/virtual machine interpreter
- Composite numbers k with no single digit factors whose factors are all substrings of k
- Concurrent computing
- Constrained genericity
- Create an object at a given address
- Cullen and Woodall numbers
- Curzon numbers
- Cyclotomic polynomial

### D

### E

- Earliest difference between prime gaps
- Echo server
- Elementary cellular automaton
- Elementary cellular automaton/Infinite length
- Elementary cellular automaton/Random number generator
- Elliptic Curve Digital Signature Algorithm
- Equal prime and composite sums
- Erdös-Selfridge categorization of primes
- Euler's constant 0.5772...
- Execute Computer/Zero
- Execute SNUSP

### F

### G

### H

### L

### M

- MD4
- Machine code
- Magic constant
- Magic squares of singly even order
- Matrix-exponentiation operator
- Matrix chain multiplication
- Mayan calendar
- Maze solving
- Median filter
- Metered concurrency
- Minesweeper game
- Minimal steps down to 1
- Minimum multiple of m where digital sum equals m
- Modular arithmetic
- Monads/List monad
- Monads/Writer monad
- Mouse position
- Multiple regression
- Mutex

### P

- P-Adic numbers, basic
- P-Adic square roots
- P-value correction
- Parallel brute force
- Parallel calculations
- Parameterized SQL statement
- Particle fountain
- Peaceful chess queen armies
- Peano curve
- Pell numbers
- Pentomino tiling
- Percentage difference between images
- Percolation/Bond percolation
- Percolation/Mean cluster density
- Percolation/Site percolation
- Periodic table
- Peripheral drift illusion
- Pinstripe/Display
- Pinstripe/Printer
- Plasma effect
- Play recorded sounds
- Polymorphism
- Polyspiral
- Prime triangle
- Primes - allocate descendants to their ancestors
- Pseudo-random numbers/Combined recursive generator MRG32k3a
- Pseudo-random numbers/Middle-square method
- Pythagoras tree

### R

- RCRPG
- RIPEMD-160
- RSA code
- Ramanujan primes/twins
- Random sentence from book
- Record sound
- Reflection/List methods
- Rendezvous
- Repunit primes
- Respond to an unknown method call
- Retrieve and search chat history
- Rhonda numbers
- Rosetta Code/Count examples
- Rosetta Code/Find unimplemented tasks
- Ruth-Aaron numbers

### S

- SHA-1
- SHA-256
- SHA-256 Merkle tree
- SOAP
- SQL-based authentication
- Search in paragraph's text
- Selectively replace multiple instances of a character within a string
- Send an unknown method call
- Sequence of primorial primes
- Set right-adjacent bits
- Sierpinski pentagon
- Sierpinski square curve
- Sierpinski triangle/Graphical
- Simple turtle graphics
- Simple windowed application
- Simulate input/Mouse
- Singleton
- Smallest number k such that k+2^m is composite for all m less than k
- Snake
- Sockets
- Sokoban
- Sort an outline at every level
- Strassen's algorithm
- Sudan function
- Sutherland-Hodgman polygon clipping
- Synchronous concurrency

### T

### U

### 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 REXX (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
- Camel case and snake case
- Checksumcolor
- Chess player
- Cipolla's algorithm
- Code Golf: Code Golf
- Combinations with repetitions/Square digit chain
- Compiler/Preprocessor
- Compiler/Simple file inclusion pre processor
- Compiler/Verifying syntax
- 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
- Create an executable for a program in an interpreted language
- Create an object/Native demonstration
- Create your own text control codes
- Cross compilation
- Curve that touches three points
- Cycles of a permutation

### D

### E

### F

### G

### I

### L

### M

### P

### R

- Railway circuit
- Ramanujan primes
- Range modifications
- Raster bars
- Recursive descent parser generator
- Red black tree sort
- Remote agent/Agent interface
- Remote agent/Agent logic
- Remote agent/Simulation
- Resistance calculator
- Resistance network calculator
- Robots
- Rodrigues’ rotation formula
- Rosetta Code/List authors of task descriptions
- Rosetta Code/Run examples
- Rosetta Code/Tasks without examples
- Round-robin tournament schedule
- Run as a daemon or service

### S

- Safe and Sophie Germain primes
- Sanitize user input
- Segmentation fault protection
- Self-hosting compiler
- Sierpinski curve
- Simulated annealing
- Singly-linked list/Element removal
- Smallest enclosing circle problem
- Smallest multiple
- Solve a Rubik's cube
- Solve equations with substitution method
- Solve hanging lantern problem
- Solve triangle solitare puzzle
- Solving coin problems
- Sort primes from list to a list
- Sorting algorithms/Tree sort on a linked list
- Starting a web browser
- Suffix tree
- Sum of square and cube digits of an integer are primes
- Sum of two adjacent numbers are primes
- Summation of primes
- Sunflower fractal

### T

### U

### W

## Requiring Attention[edit]

### Examples[edit]

These tasks have implementations in REXX, 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 REXX which require attention; with your knowledge and assistance, we can improve the quality of the site's content.

## Not Considered[edit]

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

## End of List[edit]

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