RoundAbout

RoundAbout

Designed by	User:AndrewToasterr
Appeared in	2022
Memory system	stack and heap-based
Dimensions	Two-dimensional
Computational class	Unknown
Reference implementation	Created, testing
File extension(s)	.rbout

This page is still being worked on!

RoundAbout is a two-dimensional esoteric programming language. Code is placed on a two-dimensional grid, called Map.

Language overview

A RoundAbout program consists of a size definition and the actual program code inside. Each cell in the map consists of a single UTF-8 character. The program code is then executed by looking at the current symbol below the cursor, and then executing an instruction based on the selected mode. Any empty spaces should be considered a space (U+0020). At the start of execution the cursor is positioned on the top-left corner (at 0,0) and the direction is set to right. The following example is a CAT program

//21,2
$?; =+1; &^; @v; $-+;
              ~

Instructions

Due to the fact that RoundAbout has multiple execution modes, each symbol can have different meanings in different contexts.

Contextless

These instructions can be used regardless of mode

Cmd	Name	Condition	Description
~	Halt	None	Halts the program execution
;	Reset	None	Sets the mode to Traversal

Traversal

Cmd	Name	Condition	Description
@	Set-conditionaltraversal	None	Sets the mode to Conditional Traversal
?	Set-compare	None	Sets the mode to Comparison
&	Set-flags	None	Sets the mode to Comparison
%	Set-operation	None	Sets the mode to Operation
=	Set-stack	None	Sets the mode to Stack
[	Set-heap	None	Sets the mode to Heap
$	Set-io	None	Sets the nice to IO
#	Set-map	None	Sets the mode to Map
>	Flow-right	None	Sets the direction to right
<	Flow-left	None	Sets the direction to left
v	Flow-down	None	Sets the direction to down
^	Flow-up	None	Sets the direction to up
/	Flow-fsreflect (forward slash reflect)	None	When direction is up or right, set direction to right-up. When direction is down or left, set direction to left-down. When direction is right-down, set direction to left-up. When direction is left-up, set direction to right-down. Otherwise preserve direction
\	Flow-bsreflect (back slash reflect)	None	When direction is up or left, set direction to left-up. When direction is down or right, set direction to right-down. When direction is left-down, set direction to right-up. When direction is right-up, set direction to left-down. Otherwise preserve direction
|	Flow-vreflect (vertical reflect)	None	When direction is right, set direction to left. When direction is left, set direction to right. When direction is right-down or left-down, set direction to down. When direction is right-up or left-up, set direction to up. Otherwise preserve direction
-	Flow-hreflect (horizontal reflect)	None	When direction is down, set direction to up. When direction is up, set direction to down. When direction is right-down or right-up, set direction to down. When direction is left-down or left-up, set to left. Otherwise preserve direction
+	Flow-preflect (plus reflect)	None	Set direction randomly to either right, left, up, or down
x	Flow-xreflect (cross reflect)	None	Set direction randomly to either right-down, right-up, left-down, left-up
*	Flow-sreflect (star reflect)	None	Set direction randomly to either right, right-down, right-up, left, left-down, left-up, down, or up

Conditional traversal

This is an extension to the basic traversal mode where any instructions are only executed if ResultFlag is set to true.

Comparison

This mode is used to compare values on the stack, therefore to execute such an instruction the stack has to have at least two values.

Cmd	Name	Condition	Description
>	Compare-greaterthan	At least two values on the stack	Compares the two top most values (a, b) on the stack using b > a and sets ResultFlag to the result
<	Compare-lessthan	At least two values on the stack	Compares the two top most values (a, b) on the stack using b < a and sets ResultFlag to the result
=	Compare-equal	At least two values on the stack	Compares the two top most values (a, b) on the stack using b == a and sets ResultFlag to the result
!	Compare-notequal	At least two values on the stack	Compares the two top most values (a, b) on the stack using b != a and sets ResultFlag to the result

Flags

This mode is used to track results of certain instructions. The flags values are stored in a binary number that is arbitrarily large. Right now only six bits are used, but sixteen bits are reserved for runtime usage. This means when using custom you should either use bit 0 or use values above 65535 (2^16 - 1)

Reserved Bits Table

	Name	Description
Bit 0	ResultFlag	This is a general flag that represent whether some action succeeded or not
Bit 1	ComplexRoot	Set when taking a root results in a complex value
Bit 2	DivisionByZero	Set when any division/modulo by zero is performed. Currently there are 3 scenarios: Division, Modulo, and 0th Root
Bit 3	ResultTruncated	Set when division had a remainder
Bit 4	ReadNoDigits	Set when Stack-read read no digits
Bit 5	InvalidValue	Set when an invalid was passed to an instruction
Bit 6	Utf8Error	Set when encoding/decoing values using UTF-8 codec failed
Bit 7	Reserved Bit	This is a reserved bit, but as of now has yet no functionality
Bit 8	Reserved Bit	This is a reserved bit, but as of now has yet no functionality
Bit 9	Reserved Bit	This is a reserved bit, but as of now has yet no functionality
Bit 10	Reserved Bit	This is a reserved bit, but as of now has yet no functionality
Bit 11	Reserved Bit	This is a reserved bit, but as of now has yet no functionality
Bit 12	Reserved Bit	This is a reserved bit, but as of now has yet no functionality
Bit 13	Reserved Bit	This is a reserved bit, but as of now has yet no functionality
Bit 14	Reserved Bit	This is a reserved bit, but as of now has yet no functionality
Bit 15	Reserved Bit	This is a reserved bit, but as of now has yet no functionality

Instructions

Cmd	Name	Condition	Description
|	Flags-true	At least one value on the stack	Reads a number, if non-negative then performs flags = flags | value. If read number is negative, set InvalidValue flag to TRUE
&	Flags-false	At least one value on the stack	Reads a number, if non-negative then performs flags = flags & ~value. If read number is negative, set InvalidValue flag to TRUE
^	Flags-invert	At least one value on the stack	Reads a number, if non-negative then performs flags = flags ^ value. If read number is negative, set InvalidValue flag to TRUE
>	Flags-push	None	Pushes the Flags' value onto the stack
?	Flags-push	At least one value on the stack	Pops a value off the stack, if non-negative then performs (flags & value) == value and saves the result to ResultFlag. If value is negative, set InvalidValue flag to TRUE

Operation

This mode is used for operating with values on the stack.

Cmd	Name	Condition	Description
+	Operation-add	At least two values on the stack	Pops two values of the stack and adds them together using b + a
-	Operation-sub	At least two values on the stack	Pops two values of the stack and subtracts them from each other and pushes the result onto the stack using b - a
*	Operation-mul	At least two values on the stack	Pops two values of the stack and multiplies them together and pushes the result onto the stack using b * a
/	Operation-div	At least two values on the stack	Pops two values of the stack and performs integer division and pushes the result onto the stack using b / a
^	Operation-pow	At least two values on the stack	Pops two values of the stack and calculates the power and pushes it onto the stack using b ^ a
\	Operation-root	At least two values on the stack	Pops two values of the stack and calculate the nth root and push the truncated result onto the stack using b√a
%	Operation-mod	At least two values on the stack	Pops two values of the stack and performs integer division and pushes the remainder onto the stack them using b % a
|	Operation-or	At least two values on the stack	a
&	Operation-and	At least two values on the stack	Pops two values of the stack and performs bitwise AND and pushes the result onto the stack them using b & a
v	Operation-xor	At least two values on the stack	Pops two values of the stack and performs bitwise XOR and pushes the result onto the stack them using b ^ a
>	Operation-rshift	At least two values on the stack	Pops two values of the stack and performs bitwise right shift and pushes the result onto the stack them using b >> a
<	Operation-lshift	At least two values on the stack	Pops two values of the stack and performs bitwise left shift and pushes the result onto the stack them using b << a
!	Operation-invert	At least one value on the stack	Applies bitwise inversion to the topmost item on the stack

Stack

Cmd	Name	Condition	Description
+	Stack-push	None	Read digits until a non-digit character is encountered and push read value onto the stack. If no digits were read, push 0
-	Stack-pop	At least one value on the stack	Pops a value off the stack
*	Stack-swap	At least two values on the stack	Swaps the two topmost values on the stack
>	Stack-save	At least one value on the stack	Pop a value off the stack and set it to the current cell in the heap
<	Stack-load	None	Push a value equal to the current cell in the heap
?	Stack-any	None	Set ResultFlag to true if stack is not empty, otherwise set to false
:	Stack-dupe	At least one value on the stack	Duplicates the top value on the stack
&	Stack-clear	None	Clears the stack

Heap

Cmd	Name	Condition	Description
>	Heap-rshift	None	Moves cell pointer right
<	Heap-lshift	None	Moves cell pointer left
#	Heap-jump	At least one value on the stack	Pops a value off the stack and moves pointer to such place
*	Heap-home	None	Move cell pointer to 0
+	Heap-increment	None	Increment value in current cell by one
-	Heap-decrement	None	Decrement value in current cell by one
0	Heap-null	None	Set value in current cell to 0
&	Heap-clear	None	Set all cells to 0

IO

Cmd	Name	Condition	Description
+	IO-write	At least one value on the stack	Pop a value off the stack and write it to STDOUT using UTF-8 encoding
-	IO-read	None	Read a UTF-8 character from STDIN and push it's value onto the stack. If no character is read, push -1
?	IO-any	None	If a character can be read from STDIN set ResultFlag to true, otherwise set to false

Map

Cmd	Name	Condition	Description
+	Map-read	None	Advance cursor, read a UTF-8 character from the map at current location and push it's value onto stack
-	Map-write	At least one value on the stack	Advance cursor, pop a value off the stack, convert it to a UTF-8 character and set write it to the current location on the map
*	Map-null	None	Advance cursor, set the character at current location to a space (U+0020)
#	Map-jump	At least two values on the stack	Pop two values off the stack (y, x) and then set cursor location to (x, y). If out-of-bound, wrap around
>	Map-wincrement (width increment)	None	Increase the map's width by one
<	Map-wdecrement (width decrement)	Map width greater than 1	Decrease the map's width by one
v	Map-hincrement (height increment)	None	Increase the map's height by one
^	Map-hdecrement (height decrement)	Map height greater than 1	Decrease the map's height by one
W	Map-readwidth	None	Push a value onto the stack equal to the map's width
H	Map-readheight	None	Push a value onto the stack equal to the map's height
X	Map-readx	None	Push a value onto the stack equal to the cursor's X coordinate
Y	Map-ready	None	Push a value onto the stack equal to the cursor's Y coordinate