Category:Factor
This programming language may be used to instruct a computer to perform a task.
Official website |
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Execution method: | Compiled (machine code) |
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Garbage collected: | Yes |
Parameter passing methods: | By reference |
Type safety: | Safe |
Type compatibility: | Duck |
Type expression: | Implicit |
Type checking: | Dynamic |
Lang tag(s): | factor |
See Also: |
Factor is a stack-based, concatenative, general-purpose programming language with a focus on practicality.
Initially developed by Slava Pestov, Factor began life in 2003 as a scripting language written for a game. The implementation was originally an interpreter written in Java, but has since gained an optimizing compiler and has been rewritten in Factor with a minimal C++ core. Read more about Factor's implementation history here. Factor is still being developed by dozens of contributors, with the latest stable release in August 2023.
Factor is a stack language similar to, but of a higher level than, Forth. Factor is a concatenative language, meaning that rather than applying functions to arguments (applicative languages) to evaluate things, we compose functions to evaluate a single piece of data — the entire program up until that particular point. In Factor, the basic structure of data flow is function composition. That is, foo bar baz
is equivalent to baz(bar(foo()))
in an applicative language. This offers a nice left-to-right style of reading and data flow.
In Factor, we tend to name data flow operations rather than values. In an applicative language, you might write
var x = ...;
var y = foo(x);
var z = bar(x);
In Factor this is a data flow pattern called bi
.
[ foo ] [ bar ] bi
This says, "apply foo
to the object at the top of the data stack, and apply bar
to it as well." Rather than naming the values x, y, and z, we named the data flow pattern.
Factor comes with many practical features, including a REPL, a self-contained help browser, an object inspector, a debugger/code walker, a deployment tool, editor integration for most popular text editors and IDEs, and introspection capabilities useful for developers. Factor has a fully-featured library, including things such as an HTTP server/client, bindings to graphics libraries and databases, a C FFI, a cross-platform GUI framework, on down to niche things like polynomial arithmetic. Factor features an object system that takes inspiration from Common Lisp and Self.
Most code tends to be expressed naturally in a functional manner. Factor comes with combinators (higher-order functions) typically seen in functional languages, such as map
, filter
, reduce
, and many more. Although most things can be done efficiently without mutation, Factor doesn't shy away from it when it's useful. Mutating words end with exclamation points (by convention). Factor provides lexical and dynamic variables which can make writing imperative code more natural, or allows one to clean up code that performs a lot of stack shuffling.
One of Factor's greatest strengths is its ability to factor words into smaller words. Due to the nature of concatenative programming, this is typically a cut and paste job that can be done almost anywhere there is whitespace. Factor also has impressive metaprogramming capabilities. Since Factor is almost entirely written in Factor, there is full introspection support, including seamless access to Factor's parser, allowing one to define new syntax. Factor also offers Lisp-style macros, and in general, Factor code can be treated like a collection (homoiconicity).
About Factor examples on Rosetta Code
Most of the newer examples are meant to be copied and pasted directly into the listener (Factor's REPL) where they should run without issue. In order to deploy the examples to binaries or run them as scripts, you'll need to put them in a vocabulary (e.g. IN: myvocab
and set a MAIN:
word which acts as the entry point for the program. If an example doesn't run, it probably means that the example only works in an older version of Factor. Most of the time, this is because certain words have been changed without maintaining backwards compatibility (e.g. iota
became <iota>
in Factor 0.98).
For this reason, it is advised that examples use the works with
template to indicate which version of Factor the example works with. For example,
{{works with|Factor|0.98}}
becomes
Todo
Tasks not implemented in Factor
Links
Subcategories
This category has the following 3 subcategories, out of 3 total.
@
- Factor examples needing attention (empty)
- Factor Implementations (empty)
- Factor User (19 P)
Pages in category "Factor"
The following 200 pages are in this category, out of 1,001 total.
(previous page) (next page)S
- Show ASCII table
- Show the (decimal) value of a number of 1s appended with a 3, then squared
- Show the epoch
- Sierpinski arrowhead curve
- Sierpinski carpet
- Sierpinski curve
- Sierpinski square curve
- Sierpinski triangle
- Sierpinski triangle/Graphical
- Sieve of Eratosthenes
- Simple windowed application
- Singleton
- Singly-linked list/Element definition
- Singly-linked list/Element insertion
- Singly-linked list/Traversal
- Sleep
- Sleeping Beauty problem
- Smallest multiple
- Smallest numbers
- Smallest power of 6 whose decimal expansion contains n
- Smallest square that begins with n
- Smarandache prime-digital sequence
- Smith numbers
- Sockets
- Solve the no connection puzzle
- Sort a list of object identifiers
- Sort an array of composite structures
- Sort an integer array
- Sort disjoint sublist
- Sort numbers lexicographically
- Sort primes from list to a list
- Sort stability
- Sort three variables
- Sort using a custom comparator
- Sorting algorithms/Bead sort
- Sorting algorithms/Bogosort
- Sorting algorithms/Bubble sort
- Sorting algorithms/Cocktail sort
- Sorting algorithms/Gnome sort
- Sorting algorithms/Insertion sort
- Sorting algorithms/Merge sort
- Sorting algorithms/Permutation sort
- Sorting algorithms/Quicksort
- Sorting algorithms/Selection sort
- Sorting algorithms/Sleep sort
- Sorting algorithms/Stooge sort
- Soundex
- Sparkline in unicode
- Special divisors
- Special factorials
- Special neighbor primes
- Spelling of ordinal numbers
- Spinning rod animation/Text
- Spiral matrix
- Split a character string based on change of character
- Square but not cube
- Square-free integers
- Stack
- Stack traces
- Stair-climbing puzzle
- Start from a main routine
- Statistics/Basic
- Statistics/Normal distribution
- Steady squares
- Stem-and-leaf plot
- Stern-Brocot sequence
- Stirling numbers of the first kind
- Stirling numbers of the second kind
- Strange numbers
- Strange plus numbers
- Strange unique prime triplets
- String append
- String case
- String comparison
- String concatenation
- String interpolation (included)
- String length
- String matching
- String prepend
- Strip a set of characters from a string
- Strip block comments
- Strip comments from a string
- Strip control codes and extended characters from a string
- Strip whitespace from a string/Top and tail
- Strong and weak primes
- Substitution cipher
- Substring
- Substring primes
- Substring/Top and tail
- Successive prime differences
- Sudan function
- Sum and product of an array
- Sum and product puzzle
- Sum data type
- Sum digits of an integer
- Sum multiples of 3 and 5
- Sum of a series
- Sum of divisors
- Sum of elements below main diagonal of matrix
- Sum of first n cubes
- Sum of primes in odd positions is prime
- Sum of square and cube digits of an integer are primes
- Sum of squares
- Sum of the digits of n is substring of n
- Sum of two adjacent numbers are primes
- Summarize and say sequence
- Summarize primes
- Summation of primes
- Super-d numbers
- Super-Poulet numbers
- Sylvester's sequence
- Symmetric difference
- System time
T
- Take notes on the command line
- Tau function
- Tau number
- Teacup rim text
- Temperature conversion
- Terminal control/Ringing the terminal bell
- Ternary logic
- Test a function
- Test integerness
- Text between
- Text completion
- Text processing/2
- Text processing/Max licenses in use
- Textonyms
- The Name Game
- The Twelve Days of Christmas
- Thue-Morse
- Time a function
- Tokenize a string
- Tokenize a string with escaping
- Top rank per group
- Topswops
- Totient function
- Towers of Hanoi
- Trabb Pardo–Knuth algorithm
- Tree traversal
- Trigonometric functions
- Triplet of three numbers
- Tropical algebra overloading
- Truncatable primes
- Truth table
- Twin primes
- Two bullet roulette
- Two identical strings
- Two sum
- Type detection
U
V
W
- Walk a directory/Non-recursively
- Walk a directory/Recursively
- Walsh matrix
- Water collected between towers
- Web scraping
- Weird numbers
- Wieferich primes
- Wilson primes of order n
- Window creation
- Word frequency
- Word wheel
- Word wrap
- Words containing "the" substring
- Words from neighbour ones
- Write entire file