Knowledge Base
Uiua
9 min read

Stack-based array programming language with a unique glyph-based syntax. Each built-in function is a single Unicode character. Code is written right-to-left. Runs in the browser via WebAssembly.

Core concepts

• Stack-based: Functions consume from and push to an implicit stack
• Array-oriented: All values are arrays; scalar = rank-0 array
• Tacit/point-free: Functions compose without naming arguments
• Glyphs: Built-ins are single Unicode chars (e.g. + add, ⇌ reverse, △ shape)

Basic syntax

uiua
# Numbers push to the stack
1 2 3 # stack: [1, 2, 3]

# Add consumes two, pushes one
+ 1 2 # → 3

# Arrays
[1 2 3 4 5]

# String
"hello"

# Arithmetic (right-to-left reads as left-to-right math)
× 2 + 1 3 # (1 + 3) × 2 = 8

Common glyphs

Algorithm

NameGlyphArgsOutputsDescription
derivative∂``1Calculate the derivative of a mathematical expression
fft``11Run the Fast Fourier Transform on an array
geometric⩜``1Convert an operation to be in geometric algebra
hsv``11Convert a color array from RGB to HSV
integral∫``1Calculate an antiderivative of a mathematical expression
oklch``11Convert a color array from RGB to Oklch
path````2Find the shortest path between two things
recur````1Execute a recursive or tree algorithm
regex``21Match a regex pattern

Arguments

NameGlyphArgsOutputsDescription
above◠``1Keep all arguments to a function before the outputs
backward˜``1Call a function with its arguments swapped
below◡``1Keep all arguments to a function after the outputs
both∩``1Call a function on two sets of values
bracket⊓``1Call two functions on two distinct sets of values
by⊸``1Call a function but keep its last argument after its outputs
dip⊙``1Skip the first argument and call a function on later arguments
duplicate.12Duplicate the top value on the stack
flip:22Swap the top two values on the stack
fork⊃``1Call two functions on the same values
gap⋅``1Discard the first argument then call a function
identity∘11Do nothing with one value
off⤚``1Call a function but keep its first argument after its outputs
old reach𝄐``1Old reach
on⟜``1Call a function but keep its first argument before its outputs
pop◌10Discard the first argument
reach∪``1Call a function skipping the second argument
self˙``1Call a function with the same array as all arguments
with⤙``1Call a function but keep its last argument before its outputs

Command

NameGlyphArgsOutputsDescription
&invk``10Invoke a path with the system's default program
&runc``13Run a command and wait for it to finish
&runi``11Run a command and wait for it to finish
&runs``13Run a command with streaming IO

Comptime

NameGlyphArgsOutputsDescription
comptime````1Run a function at compile time
quote``01Convert a string into code at compile time

Constant

NameGlyphArgsOutputsDescription
etaη01The number of radians in a quarter circle
infinity∞01The biggest number
piπ01The ratio of a circle's circumference to its diameter
tauτ01The ratio of a circle's circumference to its radius

Debug

NameGlyphArgsOutputsDescription
args?00Debug print all arguments without consuming them
dump``00Preprocess and print all arguments without popping them

DyadicArray

NameGlyphArgsOutputsDescription
base⊥21Get the base digits of a number
couple⊟21Combine two arrays as rows of a new array
drop↘21Drop the first n rows of an array
find⌕21Find the occurrences of one array in another
indexin⨂21Find the first index in an array of each row of another array
indexof⊗21Find the first index of each row of one array in another
join⊂21Append two arrays end-to-end
keep▽21Discard or copy some rows of an array
mask⦷21Mask the occurrences of one array in another
match≍21Check if two arrays are exactly the same
memberof∊21Check if each row of one array exists in another
orient⤸21Change the order of the axes of an array
pick⊡21Index a row or elements from an array
rerank☇21Change the rank of an array's rows
reshape↯21Change the shape of an array
rotate↻21Rotate the elements of an array by n
select⊏21Select multiple rows from an array
take↙21Take the first n rows of an array
windows◫21The n-wise windows of an array

DyadicPervasive

NameGlyphArgsOutputsDescription
add+21Add values
atangent∠21Take the arctangent of two numbers
complexℂ21Make a complex number
divide÷21Divide values
equals=21Compare for equality
greater or equal≥21Compare for greater than or equal
greater than>21Compare for greater than
less or equal≤21Compare for less than or equal
less than<21Compare for less than
maximum↥21Take the maximum of two arrays
minimum↧21Take the minimum of two arrays
modulo◿21Modulo values
multiply×21Multiply values
not equals≠21Compare for inequality
or∨21Logical OR and greatest common divisor
powerⁿ21Raise a value to a power
subtract-21Subtract values

Encoding

NameGlyphArgsOutputsDescription
apng``21Encode an array of image frames in an APNG-encoded byte array
audio``31Encode audio into a byte array
binary``11Encode an array into a compact binary representation
bytes``21Convert a value to a byte representation
compress``21Compress bytes according to some algorithm
csv``11Encode an array into a CSV string
gif``21Encode an array of image frames in a GIF-encoded byte array
graphemes``11Convert a string to a list of UTF-8 grapheme clusters
img``21Encode an image into a byte array with the specified format
json``11Encode an array into a JSON string
layout``21Render text into an image array
parse⋕11Parse a string as a number
utf₈``11Convert a string to UTF-8 bytes
voxels``11Project a voxel array to an image
xlsx``11Encode an array into XLSX bytes

Env

NameGlyphArgsOutputsDescription
&args``01Get the command line arguments
&raw``10Set the terminal to raw mode
&ts``01Get the size of the terminal
&var``11Get the value of an environment variable

Environment

NameGlyphArgsOutputsDescription
arch``01Get the current architecture
dllext``01Get the DLL extension for the current platform
exeext``01Get the executable extension for the current platform
numprocs``01Get the number of processors on the current system
os``01Get the current operating system
osfamily``01Get the current operating system family
pathsep``01Get the primary path separator for the current platform

Ffi

NameGlyphArgsOutputsDescription
&ffi``21Call a foreign function interface
&malloc``11Allocate memory for the given number of bytes and return a pointer to it
&memcpy``21Copy data from a pointer into an array
&memfree``10Free a pointer
&memset``30Write data from an array into a pointer

Filesystem

NameGlyphArgsOutputsDescription
&cd``10Change the current directory
&fc``11Create a file and return a handle to it
&fde``10Delete a file or directory
&fe``11Check if a file, directory, or symlink exists at a path
&fif``11Check if a path is a file
&fld``11List the contents of a directory
&fmd``10Create a directory
&fo``11Open a file and return a handle to it
&frab``11Read all the contents of a file into a byte array
&fras``11Read all the contents of a file into a string
&ftr``10Move a file or directory to the trash
&fwa``20Write the entire contents of an array to a file

InversionModifier

NameGlyphArgsOutputsDescription
anti⌝``1Invert the behavior of a function, treating its first argument as a constant
obverse⌅``1Define the various inverses of a function
un°``1Invert the behavior of a function
under⍜``1Operate on a transformed array, then reverse the transformation

IteratingModifier

NameGlyphArgsOutputsDescription
do⍢``1Repeat a function while a condition holds
fold∧``1Apply a function to aggregate arrays
reduce/``1Apply a reducing function to an array
repeat⍥``1Repeat a function a number of times
scan\11Reduce, but keep intermediate values

Map

NameGlyphArgsOutputsDescription
get``21Get the value corresponding to a key in a map array
has``21Check if a map array has a key
insert``31Insert a key-value pair into a map array
map``21Create a hashmap from a list of keys and list values
remove``21Remove the value corresponding to a key from a map array

MappingModifier

NameGlyphArgsOutputsDescription
each∵``1Apply a function to each element of an array or arrays
group⊕``1Group elements of an array into buckets by index
inventory⍚``1Apply a function to each unboxed row of an array and re-box the results
partition⊜``1Group sequential sections of an array
rows≡``1Apply a function to each row of an array or arrays
stencil⧈21Call a function on windows of an array
table⊞``1Apply a function to each combination of rows of some arrays
tuples⧅``1Get permutations or combinations of an array

Media

NameGlyphArgsOutputsDescription
&ap``10Play some audio
&apngs``20Show an APNG
&asr``01Get the sample rate of the audio output backend
&ast``00Synthesize and stream audio
&gifs``20Show a gif
&ims``10Show an image

Misc

NameGlyphArgsOutputsDescription
&b``00Pause the execution and print the argument list
&camcap``11Capture an image from a webcam
&camlist``01List names of available webcams
&clip``01Get the contents of the clipboard
&exit``10Exit the program with a status code
&sl``10Sleep for n seconds
assert⍤20Throw an error if a condition is not met
case⍩``1Call a pattern matching case
pattern⍡``1Choose different cases based on pattern matching
pretty``11Convert a value to its pretty-printed output representation
repr``11Convert a value to its code representation
try⍣``1Call a function and catch errors
type``11Check the type of an array

MonadicArray

NameGlyphArgsOutputsDescription
bits⋯11Encode an array as bits (LSB-first)
box□11Turn an array into a box
classify⊛11Assign a unique index to each unique row in an array
deduplicate◴11Remove duplicate rows from an array
deshape♭11Make an array 1-dimensional
fall⍖11Get the indices into an array if it were sorted descending
first⊢11Get the first row of an array
fix¤11Add a length-1 axis to an array
last⊣11Get the last row of an array
length⧻11Get the number of rows in an array
occurrences⧆11Mark each row of an array with its occurrence count
range⇡11Make an array of all natural numbers less than a number
reverse⇌11Reverse the rows of an array
rise⍏11Get the indices into an array if it were sorted ascending
shape△11Get the dimensions of an array
sort⍆11Sort an array
transpose⍉11Rotate the shape of an array
unique◰11Get a mask of first occurrences of items in an array
where⊚11Get indices where array values are not equal to zero

MonadicPervasive

NameGlyphArgsOutputsDescription
absolute value⌵11Get the absolute value of a number
ceiling⌈11Round to the nearest integer towards ∞
exponentialₑ11Get the exponential of a number
floor⌊11Round to the nearest integer towards ¯∞
negate¯11Negate a number
not¬11Logical not
reciprocal⨪11Get the reciprocal of a number
round⁅11Round to the nearest integer
sign±11Numerical sign (1, ¯1, or 0)
sine∿11Get the sine of a number
sqrt√11Take the square root of a number

OtherModifier

NameGlyphArgsOutputsDescription
content◇``1Unbox the arguments to a function before calling it
evert⧋``1Call a function with its arguments' axes reversed
fill⬚``1Set the fill value for a function
memo````1Memoize a function
switch⨬``1Call the function at the given index

RNG

NameGlyphArgsOutputsDescription
gen``21Generate an array of random numbers with a seed
noise``31Generate random noise
random⚂01Generate a random number in the range [0, 1)

StdIO

NameGlyphArgsOutputsDescription
&ep``10Print a value to stderr followed by a newline
&epf``10Print a value to stderr
&p``10Print a value to stdout followed by a newline
&pf``10Print a value to stdout
&s``10Print a nicely formatted representation of a value to stdout
&sc``01Read a line from stdin

Stream

NameGlyphArgsOutputsDescription
&cl``10Close a stream by its handle
&rb``21Read n bytes from a stream
&rl``11Read lines from a stream
&rs``21Read characters formed by n bytes from a stream
&ru``21Read from a stream until a delimiter is reached
&seek``20Move to an absolute position in a file stream
&w``20Write an array to a stream

Tcp

NameGlyphArgsOutputsDescription
&fetch``11Fetch data from a url
&tcpa``11Accept a connection with a TCP or TLS listener
&tcpaddr``11Get the connection address of a TCP socket
&tcpc``11Create a TCP socket and connect it to an address
&tcpl``11Create a TCP listener and bind it to an address
&tcpsnb``11Set a TCP socket to non-blocking mode
&tcpsrt``20Set the read timeout of a TCP socket in seconds
&tcpswt``20Set the write timeout of a TCP socket in seconds
&tlsc``11Create a TCP socket with TLS support
&tlsl``31Create a TLS listener and bind it to an address

Thread

NameGlyphArgsOutputsDescription
pool````1Spawn a thread in a thread pool
recv``11Receive a value from a thread
send``20Send a value to a thread
spawn````1Spawn a thread
tryrecv``11Try to receive a value from a thread
wait``11Wait for a thread to finish and return its results

Time

NameGlyphArgsOutputsDescription
datetime``11Get the date and time information from a time
now``01Get the current time in seconds
timezone``01Get the local timezone offset

UDP

NameGlyphArgsOutputsDescription
&udpb``11Bind a UDP socket
&udpr``12Receive a single message from a UDP socket
&udps``30Send a message on a UDP socket
&udpsml``20Set the maximum message length for incoming messages

Functions

uiua
# Named function
Square ← × . # dup then multiply

# Call it
Square 5 # → 25

Try it

• uiua.org pad — online playground
• cargo install uiua for the CLI