instructions.md

Instructions

Input / Output

op	Description
p	Pop and print with no newline.
P	Pop and print with a newline.
q	Peek and print with no newline.
Q	Peek and print with a newline.
|_	(space, not underscore) Print a single space character.
|`	Dump debug state. Shows registers, iteration info, and both stacks. In the web-based environment, break execution.
|P	Print newline. Deprecated. Use zP instead. Deprecations don't happen often in stax, and when they do, they'll usually be accompanied by an equivalent way of accomplishing the same thing.
|u	Un-eval. Produce string representation of array. e.g. "[1, 2, 3, [4, 5]]"
|V	Array of command line arguments. This will be an empty array for non-command-line invocations.

Stack

op	Example	Name	Description
a	… a b c -> … b c a	alter-stack	Moves the third element in the stack to the top.
b	… a b -> … a b a b	both-copy	Copies the top two stack elements
c	… a -> … a a	copy	Copy the top stack element
d	… a b -> … a	discard	Pop and discard top stack element
n	… a b -> … a b a	next	Copy second element to top of stack
[	… a b -> … a a b	under	Copy second element in-place
~		input-push	Pop top item, and push it to input stack.
;		input-peek	Peek from input stack, and push to main stack.
,		input-pop	Pop from input stack, and push to main stack.
e	arr	eval	Parse string as data to be pushed on the stack. e.g. [12, 3.4, [5/6, "a string"]] Multiple top level values in the same string will be pushed separately. \", \\, \n, and \x41 are escapes.
E	arr	explode	Push all elements from array onto stack.
L	… -> […]	listify-stack	Clear both stacks, and put all items in an array back on stack.
l	int	listify-n	Pop n items, and put them in an array on top of the stack.
O	… a -> … 1 a	tuck-1	Push the value 1 under the top element of the stack.
s	… a b -> … b a	swap	Swap top two stack elements.
Z	… a -> … 0 a	tuck-0	Push the value 0 under the top element of the stack.
|d		main-depth	Size of main stack.
|D		input-depth	Size of input stack.

Numerics

op	Types	Name	Pseudo-code	Description
0123456789				Integer literal. Leading 0 is always separate number. Use A for 10. 10 is 1 and 0.
A			10	Constant 10, as in hexidecimal.
01234!56789				Float literal. ! indicates a decimal point. A trailing 0 after a ! is always a separate int literal.
+	num num	add	a + b	Add. Integers widen to fractions. Fractions widen to floats.
-	num num	sub	a - b	Subtract.
*	num num	mul	a * b	Multiply.
/	num num	div	a / b	Integers will use integer division.
%	int int	mod	a % b	Modulus.
@	frac	floor	floor(a)	Integer floor of fraction.
@	float	floor	floor(a)	Integer floor of float.
v	num	dec	a - 1	Decrement by 1.
^	num	inc	a + 1	Increment by 1.
B	frac	properize	floor(a), a%1	Properize fraction. Push integer floor, and proper remainder separately.
D	num	frac-part	a%1	Get fractional non-integer part of rational or float.
e	frac	ceil	ceiling(a)	Integer ceiling of fraction.
e	float	ceil	ceiling(a)	Integer ceiling of float.
E	int	dec-digits		Array of decimal digits. Absolute value is used in case of negative number.
E	frac	num-den		Push numerator and denominator separately.
h	int	halve	a / 2	Floor divide by 2.
h	num	halve	a / 2	Divide by 2.
H	num	un-halve	a * 2	Double.
j	float int	float-round	round(a, b)	Round float to n decimal places. Format as string.
j	float	round	round(a)	Round to nearest integer.
j	frac	round	round(a)	Round to nearest integer.
J	num	square	a ** 2	Square number.
l	frac	listify-frac	a/b -> [a b]	Turn a fraction into a 2-array of numerator and denominator.
N	number	negate	-a	Negate a number.
r	frac	numerator	numerator(a)	Get the numerator.
R	frac	denom	denom(a)	Get the denominator.
u	int	fractionalize	1 / a	Turn integer upside down; into fraction.
u	frac	invert-frac	1 / a	Turn fraction upside down; invert.
u	float	invert-float	1 / a	Floating point inversion.
U			-1	Negative unit.
|%	int int	divmod	a / b, a % b	Perform division and modulus.
|&	int int	bit-and	a & b	Bitwise and.
||	int int	bit-or	a | b	Bitwise or.
|^	int int	bit-xor	a ^ b	Bitwise xor.
|*	int int	pow	a ** b	Exponent.
|*	frac int	pow	a ** b	Exponent.
|/	int int	div-all		Divide a by b as many times as it will go evenly.
|<	int int	shift-left	a << b	Bitshift left.
|>	int int	shift-right	a >> b	Bitshift right.
|1	int	parity-sign	(-1) ** a	Power of negative one.
|2	int	2-power	2 ** a	Power of two.
|3	int	base-36		Convert to base 36.
|3	arr	base-36		Convert from base 36.
|5	num	nth-fib		Get nth fibonacci number; 0-indexed.
|6	num	nth-prime		Get nth prime; 0-indexed.
|7	num	cosine	cos(a)	Cosine in radians.
|8	num	sine	sin(a)	Sine in radians.
|9	num	tangent	tan(a)	Tangent in radians.
|a	num	abs	abs(a)	Absolute value.
|A	int	10-power	10 ** a	Power of ten.
|b	int int	convert-base		Convert to base, up to 36.
|b	arr int	convert-base		Convert from base, up to 36.
|B	int	convert-binary		Convert to binary. (base 2)
|B	arr	convert-binary		Convert from binary. (base 2)
|C	int int	choose	choose(a, b)	Binomial coefficient - calculate a choose b.
|e	int	is-even	(a + 1) % 2	Is even?
|E	int int	digits		Generate array of digit values in base. Absolute value is used in case of negative number.
|E	arr int	un-digit		Produce the number represented by the array of digits in the given base.
|f	int	factorize		Prime factorization array.
|F	int	factorial	a!	Factorial.
|g	int int	gcd		Greatest common denominator.
|H	int	base-16		Convert to hexidecimal. (base 16)
|H	arr	base-16		Convert from hexidecimal. (base 16)
|l	int int	lcm		Least common multiple.
|L	num num	log-n	log(a, b)	Logarithm in base b of a.
|m	num num	min	min(a, b)	Lower of two values.
|M	num num	max	max(a, b)	Higher of two values.
|n	int	prime-exps		Exponents of sequential primes in factorization. (eg. 20 -> [2 0 1])
|p	int	is-prime		Is prime?
|q	num	int-sqrt	floor(sqrt(abs(a)))	Integer square root of absolute value.
|Q	num	sqrt	sqrt(abs(a))	Float square root of absolute value.
:~	int	set-interior		Set all interior bits in number. The result will always be one less than a power of 2.
:!	int int	coprime	iscoprime(a, b)	Are a and b coprime?
:#	num	floatify	float(a)	Convert to float.
:-	num num	abs-diff	abs(a - b)	Absolute difference.
:@	int int	get-bit	(a >> b) & 1	Extract a single bit from an integer.
:/	int int	multiplicity		Number of times b will evenly divide a.
:+	num	sign	sign(a)	Sign; 1 for positive, -1 for negative.
:_	num num	float-div	1.0 * a / b	Float division.
:1	int	popcount		Count of set bits.
:2	num	floor-log-2	floor(log(a, 2))	Floor of log base 2.
:A	num	floor-log-10	floor(log(a, 10))	Floor of log base 10.
:b	num int int	between	b <= a < c	Value is in range?
:b	arr	binary-decode		Produce a number given as an array of bits.
:B	int arr	custom-base		Encode number in custom base from string characters.
:B	int	binary-digits		Generate array of binary digits. Absolute value is used in case of negative number.
:c	num int int	clamp	min(max(a, b), c)	Ensure value is in range.
:C	int	catalan	choose(2a,a)/(a+1)	Catalan number; number of strings with a matched pairs of brackets.
:d	int	divisors		Get all divisors of n.
:f	int	factorize-exp		Factorize into pairs of [prime, exponent].
:F	int	dist-factors		Distinct prime factors.
:g	int	low-bit		Unset all but the low set bit.
:G	int	high-bit		Unset all but the high set bit.
:J	num num	square-two	a**2, b**2	Square top two elements; useful for hypotenuse and things.
:m	int int	next-multiple		If necessary, increase a until it is a multiple of b.
:p	int	last-prime		Last prime < n.
:P	int	next-prime		Next prime >= n.
:t	int	totient	totient(a)	Euler's totient of n.
:T	int	triangular-num	a * (a+1) / 2	Get a triangular number. Deprecated. Use |+ instead.

Logic

op	Name	Description
!	not	Logical not. Produces 0 or 1. Numeric 0 and empty lists are considered falsy. All other values are truthy.
<	less	Is less than. Arrays use string-style lexicographic ordering.
>	greater	Is greater than. Arrays use string-style lexicographic ordering.
=	equal	Equals. Numberic types are coerced as necessary. Arrays are equal to scalars if their first element is equal.
?	if-then-else	If the first value, then yield the second, else the third. If the result is a block, execute it.
|4	is-array	Tests if a value is an array or not. Produces 0 or 1.

String

Strings are really just arrays of integers, but some operations are oriented towards strings anyway. In these contexts, 0 is usually converted to 32, so that 0 can be used as a space in addition to its normal codepoint.

op	Types	Name	Description
#	arr arr	count-substrings	Count occurrences of substring b in a.
"…"		string-literal	String literal stored as an array of codepoints. Unterminated string literals will be printed implicitly. ` is the escape character for ` and ". The characters 01234 yield \0 \n \t \r \v respectively when escaped. All other escaped single characters will execute as stax code and then include the popped value as a template. (Space is no-op)
`…`		compressed-string	Compressed string literal encoded with contextual Huffman trees. Not all strings can be encoded this way, but most that can will be smaller. Unterminated compressed literals will be printed implicitly.
'a		char-literal	Create a single character string literal.
.ab		two-char-literal	Create a two character string literal.
/	arr arr	split	Split on substrings.
*	arr int	repeat	Repeat string n times. If n is negative, reverse array.
*	int arr	repeat	Repeat string n times. If n is negative, reverse array.
*	arr arr	join	Join array of strings with delimiter.
$	num	tostring	Convert number to string.
$	arr	arr-tostring	Convert each element to string, and concat. Nested arrays will just be flattened.
(	arr arr	begin-with	Overwrite the end of b with a.
)	arr arr	end-with	Overwrite the beginning of b with a.
v	arr	lower	To lower case.
^	arr	upper	To upper case.
I	arr arr	substring-index	Get the index of the first occurrence of the substring.
j	arr	space-split	String split by space.
J	arr	space-join	Join strings by space.
R	arr arr arr	regex-replace	Regex replace using ECMA regex.
t	arr	trim-left	Trim whitespace from left of string.
T	arr	trim-right	Trim whitespace from right of string.
|~	arr arr	last-index-of	Get the index of the last occurrence of the substring.
|<	arr	left-align	Left align lines of text, padding to longest line.
|>	arr	right-align	Right align lines of text, padding to longest line.
||	arr int int arr	embed-grid	Embed a grid inside another grid at the specfied coordinates. Negative coordinates are not allowed. OOB extends the necessary dimensions.
|e	arr arr arr	replace-first	String replace; first instance only.
|C	arr int	center	Center string in n characters.
|C	arr	center-block	Center lines of text, using longest line.
|F	arr arr	regex-find-all	Get all regex pattern matches.
|I	arr arr	str-index-all	Find all indexes of the substring.
|j	arr	split-newline	Split string on newlines.
|J	arr	join-newline	Join strings with newline.
|q	arr arr	regex-indices	Get all indices of regex matches.
|Q	arr arr	regex-is-match	Regex matches entire string?
|s	arr arr	regex-split	Split by ECMA regex. Captured groups will be included in result.
|S	arr arr	surround	Prepend and append string/array. Wraps the first array between copies of the second.
|t	arr arr	translate	Translate first string using pairs of elements in the second array. Instances of the first in a pair will be replaced by the second.
|z	arr int	zero-fill	Fill on the left with "0" to specified length.
:~	arr	toggle-case	Toggle case of letters in string.
:.	arr	title-case	Convert string to title case.
:/	arr arr	split-once	Split on the first occurrence of a substring. Push both parts separately.
:[	arr arr	starts-with	String starts with?
:]	arr arr	ends-with	String ends with?
:{	any	parenthesize	Embed value in parentheses as string.
:}	any	bracercise	Embed value in square braces as string.
:3	arr	rot-13	Rot13 encode/decode; dual-purpose.
:c	arr int	set-case	Set case of string. If integer is zero, use upper case. Otherwise, lower.
:C	arr	invert-case	Invert case of letters a-z. Deprecated. Use :~ instead.
:D	arr int	trim-both	Trim element from both ends of string.
:D	arr arr	trim-both	Trim all characters from both ends of string.
:e	arr	excerpts	Get all contiguous subarrays.
:h	arr	taglify	Embed string in angle brackets.
:R	arr	brace-reflect	Reflect string, (<[{/ becomes \}]>)
:t	arr arr	ring-translate	Map matching elements to the subsequent element in the translation ring. The ring wraps around.
:w	arr	brace-palindromize	Concatenate all but the last character reversed. Braces and slashes are individually reversed also.
:W	arr	brace-mirror	Concatenate the string reversed. Braces and slashes are individually reversed also.

Array

op	Types	Name	Description
"…"!		crammed-array	Crammed array of integers. This uses a scheme to represent arbitrary integers in a string literal, and then uncram them. There will be at most one number per character in the string literal. Large numbers require more characters.
#	arr num	count-instances	Count instances of b in a.
#	num arr	count-instances	Count instances of b in a.
+	arr arr	concat	Concatenate arrays.
+	num arr	prepend	Prepend element to array.
+	arr num	append	Append element to array.
-	arr arr	array-diff	Remove all elements in b from a.
-	arr num	array-remove	Remove all instances of b from a.
*	matrix matrix	matrix-mul	Matrix multiplication. A matrix is any array that contains at least one array, and no non-arrays.
/	arr int	array-group	Split array into groups of specified size. The last group will be smaller if it's not a multiple. If the divisor is zero, the result will be an empty array. If the divisor is negative, the array will be reversed first.
%	arr	length	Array length
\	num num	pair	Make a 2 length array.
\	arr num	array-pair	Make array of pairs, all having identical second element.
\	num arr	array-pair	Make array of pairs, all having identical first element.
\	arr arr	zip-repeat	Make array of pairs, zipped from two arrays. The shorter is repeated as necessary.
@	arr int	element-at	Get element at 0-based modular index. (-1 is the last element)
@	arr int int ...	element-at	Get element in multi-dimensional array using all integer indices.
@	arr arr	elements-at	Get elements at all indices.
&	arr int any	assign-index	Assign non-block element at index. Negatives index backwards. OOB extends the array.
&	arr int ... int any	assign-index	Assign non-block element in multidimensional array of arrays located at specified coordinates. Negative coordinates are not allowed. OOB extends the array(s);
&	arr arr any	assign-indices	Assign element at all indices. If indices array is an array of arrays, then treat them as a path to navigate a multidimensional array of arrays.
&	arr int block	mutate-element	Mutate element at index using block.
&	arr arr block	mutate-element	Mutate element at indices using block. If indices array is an array of arrays, then treat them as a path to navigate a multidimensional array of arrays.
(	arr int	pad-right	Truncate or pad on right with 0s as necessary for target length. Negative numbers remove that number of elements.
)	arr int	pad-left	Truncate or pad on left with 0s as necessary for target length. Negative numbers remove that number of elements.
]	any	singleton	Make a 1 element array.
B	arr int	batch	Get all (overlapping) sub-arrays of specified length.
B	arr	uncons-left	Remove first element from array. Push the tail of the array, then the removed element.
D	arr	drop-first	Remove first element from array.
h	arr	first	Get first element.
H	arr	last	Get last element.
I	arr num	index-of	Get the index of the first occurrence.
I	num arr	index-of	Get the index of the first occurrence.
M	arr int	chunkify	Partition a into b chunks of almost equal size. The largest chunks come first. They're one larger than the smaller ones.
M	arr	transpose	Flip array of arrays about the diagonal. Non-array elements are considered to be singleton arrays. Arrays are padded with zeroes as necessary to preserve layout.
N	arr	uncons-right	Remove last element from array. Push the beginning of the array, then the removed element.
r	int	0-range	Make range [0 .. n-1].
r	arr	reverse	Reverse array.
R	int	1-range	Make range [1 .. n].
t	arr int	remove-left	Trim n elements from left of array.
T	arr int	remove-right	Trim n elements from right of array.
S	arr	powerset	Get all combinations of elements in array. If the array was ordered, all combinations will be in lexicographic order.
S	arr int	combinations	Get all combinations of specified size from array. If the array was ordered, all combinations will be in lexicographic order.
u	arr	unique	Keep only unique elements in array, maintaining first order of appearance.
z			Push empty array/string.
|0	arr	falsy-index	Get index of first falsy element.
|1	arr	truthy-index	Get index of first truthy element.
|2	arr	diagonal	Get the diagonal of a matrix. Missing elements are filled with 0.
|=	arr	multi-mode	Get all tied modes of array.
|+	arr	sum	Sum of array.
|!	int int	int-partitions	Get all the distinct b-length arrays of positive integers that sum to a.
|!	arr int	arr-partitions	Get all the ways of splitting array a into b pieces.
|!	arr	multi-anti-mode	Get all tied rarest elements of array.
|@	arr int	remove-at	Remove element from array at index.
|@	arr int num	insert-at	Insert element to array at index.
|#	arr arr	verbatim-count	Counts number of occurrences of b as an element of a, without any string flattening.
|%	arr int arr	embed-array	Embed c in a, starting at position b. Negative indexes from the end. OOB extend the array.
|&	arr arr	arr-intersect	Keep all elements from a that are in b.
|^	arr arr	arr-xor	Keep all elements from a that are not in b, followed by all elements in b that are not in a.
|^	arr int	multi-self-join	Generate all arrays of size b using elements from a.
|*	arr int	repeat-elements	Repeat each element in a, abs(b) times.
|*	arr arr	cross-product	Cartesian join of arrays, producing a flat array of pairs.
|/	arr arr	multi-group	Partition a into differently sized groups from b.
|-	arr arr	multiset-subtract	Remove elements in b individually from a, if they're present.
|-	arr num	remove-first	Remove first instance of b from a.
|</code>	arr arr	zip-short	Zip arrays producing pairs. The longer array is truncated.
|</code>	arr arr num	zip-fill	Zip arrays producing pairs. The shorter array is extended using the fill element.
|)	arr	rotate-right	Move the last element of an array to the front.
|)	arr int	rotate-right-n	Shift array n places to the right, rotating the end to the front.
|(	arr	rotate-left	Move the first element of an array to the end.
|(	arr int	rotate-left-n	Shift array n places to the right, rotating the front to the end.
|[	arr	prefixes	All prefixes of array.
|]	arr	suffixes	All suffixes of array.
|a	arr	any	Any elements of array are truthy?
|A	arr	all	All elements of array are truthy?
|b	arr arr	multiset-intersect	Keep the elements from a that occur in b, no more than the number of times they occur in b.
|g	arr	gcd	Greatest common denominator of array.
|G	arr	round-flatten	Flatten array of arrays using round-robin distribution. Cycle between inner arrays until all elements are reached.
|I	arr num	find-all	Find all indexes of occurrences of the value.
|l	arr	lcm	Least common multiple of array.
|L	arr arr	multiset-union	Combine elements from a and b, with each occurring the max of its occurrences from a and b.
|m	arr	min	Minimum value in array.
|M	arr	max	Maximum value in array.
|n	arr arr	multiset-xor	Combine elements from a and b, removing common elements only as many times as they mutually occur.
|N	arr	next-perm	Get the next permuation of elements in the array, ordered lexicographically.
|o	arr	ordered-indices	Calculate destination index of each element if array were to be sorted.
|p	arr	palindromize	a + reversed(a[:-1]). Always has an odd length.
|r	int int	explicit-range	Range [a .. b). If a is an array, use the opposite of its length instead. If b is an array, use its length instead.
|R	int int int	stride-range	Range [a .. b) with stride of c.
|R	arr	run-length	Encode runs of elements into an array of [element, count] pairs.
|T	arr	permutations	Get all orderings of elements in the array. Duplicate elements are not considered.
|T	arr int	permutations	Get all b-length orderings of elements in a. Duplicate elements are not considered.
|w	arr arr	trim-left-els	Remove matching leading elements from array.
|W	arr arr	trim-right-els	Remove matching trailing elements from array.
|Z	arr	rectangularize	Rectangularize an array of arrays, using "" for missing elements.
:0	arr	falsy-indices	Get all indices of falsy elements.
:1	arr	truthy-indices	Get all indices of truthy elements.
:2	arr	self-cross-product	Pairs of elements, with replacement.
::	arr int	every-nth	Every nth element in array, starting from the first.
:<	arr	col-align-left	Left-align columns by right-padding with spaces.
:>	arr	col-align-right	Right-align columns by left-padding with spaces.
:*	arr	product	Product of numbers in array.
:-	arr	deltas	Pairwise difference of array.
:+	arr	prefix-sums	Get the sums of all prefixes.
:/	arr int	split-at	Split array at index; push both parts.
:/	int arr	split-at	Split array at index; push both parts.
:\	arr arr	diff-indices	Get indices of unequal elements between arrays.
:_	arr	reduce-array	Divide all integers in array by their collective gcd.
:=	arr arr	equal-indices	Get indices of equal elements between arrays.
:!	arr	all-partitions	Get all the ways of splitting array into pieces.
:|	arr	column-align	Right pad each column to equal length.
:@	arr	truthy-count	Count the number of truthy elements in the array.
:,	arr arr	zip-end	Zip arrays producing pairs. The longer array has its prefix dropped, so that the ends of the arrays align.
:(	arr	left-rotations	All left rotations, starting from original.
:)	arr	right-rotations	All right rotations, starting from original.
:^	arr	non-descending	Is array non-descending? (has no adjacent pair of descending elements)
:v	arr	non-ascending	Is array non-ascending? (has no adjacent pair of ascending elements)
:a	arr	minima-indices	Get indices of array minima.
:A	arr	maxima-indices	Get indices of array maxima.
:B	arr arr	element-repeats	Repeat element in a by corresponding integer in b, wrapped. e.g. "abcdef", [0,1,2] -> "bcceff"
:c	arr	coalesce	Get first truthy element of array.
:d	arr	median	Get the median of array. Integers produce a rational result. Floats produce a float.
:f	arr	flatten	Flatten array; for each element of the array unwrap it if it's an array. e.g. [3,4,[5,[6]]] -> [3,4,5,[6]]
:F	arr	falsy-indices	Get all indices of falsy elements. Deprecated. Use :0 instead.
:g	arr	run-elements	Remove adjacent duplicate elements from array.
:G	arr	run-lengths	Get the lengths of runs of duplicate elements.
:I	arr arr	find-index-all	For each element in b, find the index of the first occurrence in a.
:J	arr	squarify	Wrap array into smallest fitting square, filling any extra spaces with 0.
:m	arr int	repeat-to	Repeat array until it is exactly length n.
:m	arr	mirror	Append reversed copy to array.
:M	arr	mode	Mode. In case of tie, the last element to appear wins.
:o	arr arr	overlay	Keep the maximum element respective element from two arrays.
:p	arr	shortest-suffixes	Keep suffixes of arrays only as long as shortest array.
:P	arr	shortest-prefixes	Keep prefixes of arrays only as long as shortest array.
:r	arr arr	replace-all	Replace all substring occurrences.
:r	int	centered-range	Make range [-n .. n] centered around 0.
:s	arr	span	Get the span of an array. (maximum minus minimum)
:S	arr arr	is-superset-of	Is a a (non-strict) superset of b?
:T	arr	truthy-indices	Get all indices of truthy elements.
:u	arr	multi-single	Array contains exactly 1 distinct element?
:V	arr	mean	Mean of array. (rational or float)

Blocks

op	Types	Name	Description
{			Begin a block. Blocks can be ended by any block terminator, not just }.
}			Terminate a block and push to stack. If there is not a block currently open, start program execution over.
*	int block	do-times	Perform block n times.
*	block int	do-times	Perform block n times.
!	block	execute-block	Execute a block. Does not terminate a block.
/	arr block	group-by	Group adjacent values that produce equal values using the block. Does not terminate a block.
(	arr block	partition-when	Partition the original array into consecutive subarrays that begin when the block produces a truthy value. The block is provided with the element following the boundary.
)	arr block	partition-when-pair	Partition the original array into consecutive subarrays that begin when the block produces a truthy value. The block is provided with the pair of elements around the boundary.
B	block	triple-execute	Execute a block thrice. Does not terminate a block.
C	any	cancel	If value is truthy, cancel current block execution.
C	arr block	collect	Reduce using block, but collect each value in result array. Does not terminate a block.
D	int	do-times	Execute the rest of the program n times. _ will give the 1-based iteration count.
D	block	double-execute	Execute a block twice. Does not terminate a block.
e	block	min-by	Get the values which yield the minimum value when applying the block to the array. Does not terminate a block.
E	block	max-by	Get the values which yield the maximum value when applying the block to the array. Does not terminate a block.
f	arr block	filter	Terminate a block and filter array using it as a predicate.
f	arr	filter-short	If there is no open block, use the rest of the program as the predicate. Print passing elements on separate lines.
F	arr block	foreach	Terminate a block. Push each element of the array, and execute the block for each.
F	arr	foreach-short	If there is no open block, use the rest of the program as the block. Execute it after pushing each element.
F	int	for-short	Perform foreach-short using the range [1 .. n].
g		generator	Generate values. See generators for details.
G		goto	Jump to an unmatched trailing } at the end of the program. If there are are none, jump to the beginning of the current program. Come back when finished.
h	arr block	take-while	Keep run of matching elements, if any at the beginning of the array. Does not terminate a block.
H	arr block	take-while-end	Keep run of matching elements, if any at the end of the array. Does not terminate a block.
i		index	Get the current 0-based iteration index of the inner loop.
|;		iteration-parity	Get the parity of the current iteration index. (0 or 1)
|i		outer-index	Get the 0-based iteration index of the outer loop.
I	arr block	index-of-block	Get the index of the first element that yields a truthy value from the block. Does not terminate a block.
j	arr block	first-match	Get the first match from the array - the first value for which the block produces a truthy value. Does not terminate a block.
J	arr block	last-match	Get the last match from the array - the last value for which the block produces a truthy value. Does not terminate a block.
k	arr block	reduce	Terminate a block and reduce (fold) using the block.
k	int block	reduce-range	Terminate a block and reduce (fold) [1 .. n] using the block.
k	int	reduce-short	If there is no open block, use the rest of the program as the block to reduce the array. Implicitly print the result.
k	arr	reduce-short-range	If there is no open block, use the rest of the program as the block to reduce [1 .. n]. Implicitly print the result.
K	arr arr block	cross-map	Terminate a block and map using over a cartesian join. Both elements will be pushed to the stack. _ will also push both to stack. The result will be an array of arrays.
m	arr block	map	Terminate a block and map using a block. If the block execution is cancelled, that element won't be included in the result.
m	arr	map-short	If there is no open block, use the rest of the program as the block. Print each mapped element with a new-line.
m	int	map-range-short	Use the rest of the program as a block to map [1 .. n]. Print each mapped element with a new-line.
M	any block	maybe	Execute block if value is truthy. Does not terminate a block.
N	block	repeat-from-input	Pop integer from input stack, and repeats block that many times. {...}N is functionally equivalent to {...},*
o	arr block	order	Terminate a block and order array by key. If there are no open blocks, order the array itself.
t	arr block	trim-start-block	Remove elements from the start of the array that are matched the block predicate. Does not terminate a block.
T	arr block	trim-end-block	Remove elements from the end of the array that are matched the block predicate. Does not terminate a block.
w	block	do-while	Terminate a block and iterate until it produces a falsy value.
w		do-while-short	If there is no open block, use the rest of the program as the block.
W	block	while	Terminate a block and iterate forever. Cancelling will terminate, as with all blocks.
W		while-short	If there is no open block, use the rest of the program as the block.
_		current	Get the current iteration value. If there are no blocks executing, this will be all of standard input, as one string.
|c		contend	Assert top of stack is truthy. Cancel if not. Do not pop.
|I	arr block	filter-index	Get all indexes in the array that produce a truthy value from the block.

Registers

op	Description
x	Value of register x. Default is parsed integer value from standard input, or 0.
X	Peek and write register x.
|x	Decrement register x and push. If x is not an integer, set it to 0 first.
|X	Increment register x and push. If x is not an integer, set it to 0 first.
y	Value of register y. Default is first line of standard input.
Y	Peek and write register y.
|y	Decrement register y and push. If y is not an integer, set it to 0 first.
|Y	Increment register y and push. If y is not an integer, set it to 0 first.

Prefix Directives

Some instructions behave differently when they are the first character in a program. These directives do not apply if the implicit eval of standard input succeeded.

char	Name	Description
f	line-filter	Use the rest of the program to filter input lines. Print lines that produce a truthy result.
F	line-foreach	Execute the rest of the program once for each line of input.
m	line-map	Map each line of standard input. Print each result with a newline.
i	no-eval	Suppress auto-eval. e.g. If the input is a binary number, this will prevent incorrectly parsing it as an integer.

Constants

op	Value
|?	source of current program for quines or something
V?	Version info
V!	"[a-z]"
V@	"[A-Z]"
V#	"[a-zA-Z]"
V$	"[a-z]+"
V)	"[A-Z]+"
V^	"[a-zA-Z]+"
V&	"[a-z]*"
V*	"[A-Z]*"
V(	"[a-zA-Z]*"
V:	"http://"
V;	"https://"
V0	rational 0/1
V2	0.5
V3	semitone ratio in equal temperment (pow(2, 1/12))
V/	pi/3
V%	[0, 0]
VA	"ABCDEFGHIJKLMNOPQRSTUVWXYZ"
Va	"abcdefghijklmnopqrstuvwxyz"
Vb	"()[]{}<>"
VB	256
VC	"BCDFGHJKLMNPQRSTVWXYZ"
Vc	"bcdfghjklmnpqrstvwxyz"
Vd	"0123456789"
VD	sqrt(2)
Ve	natural log base
VE	sqrt(3)
Vh	"0123456789abcdef"
VH	"0123456789ABCDEF"
Vi	negative infinity
VI	positive infinity
Vk	1000
Vl	"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
VL	"0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
Vm	0x7ffffffff
VM	1000000
Vn	newline (newline is also A])
Vp	all printable ascii characters
VP	pi
Vq	pi/2
Vs	all ascii whitespace
VS	4/3 pi
Vt	tau (2pi)
VT	10.0
Vu	pow(2, 32)
VV	"AEIOU"
Vv	"aeiou"
VW	"0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"
Vw	"0123456789abcdefghijklmnopqrstuvwxyz"