spreadsheetlang

A Psi-inspired and spreadsheet-like esoteric programming language.

Table Of Contents

• Introduction
• Execution Model
• Expressions and Operators
• Examples
• Installing

Introduction

SPREADSHEET is a Psi-inspired and spreadsheet-like esolang. Like Hat Trick, it is evaluated using RPN. File extensions for SPREADSHEET programs are .sprd, and SPREADSHEET comments begin with //. SPREADSHEET, unlike Tailor, is not forgiving, but it basically never throws errors anyways.

Execution Model

The SPREADSHEET execution model consists of a grid of formulas, like a spreadsheet. The grid is unbounded in all four directions, and is updated once every tick. The formulas have a command attached to them, which is either V, S, F, or I.

• The V command defines an expression to be evaluated.
• The F command takes two expressions, and sets the cell denoted by the first expression to a string containing a valid line of SPREADSHEET code.
• The S command sets the cell denoted by the first expression to a V command containing the evaluated value of the second expression.
• The I command takes input from the user.

The SPREADSHEET program's lines describe the content of the grid. Every line of a SPREADSHEET program is of a specific format:

V<coordinate>: <expression>
S<coordinate>: <expression> <= <expression>
F<coordinate>: <expression> <= <expression>
I<coordinate>

All changes to cells are applied at the end of the tick, in the order the V and S commands were evaluated. The grid is updated every in this way:

• Evaluate all cells with the F or S command first, with the distance from the center serving as the order, and counterclockwise angle about the origin as a tiebreaker.
  • If these cells depend on other cells that have not yet been evaluated this tick, evaluate those cells first.
• Apply the changes made by the F and S commands to the grid.
• If the cell (0,0) contains a value, output it to the user, and clear the cell.
• If the grid has not changed since the last tick, halt the program.

To reiterate, every cell in a SPREADSHEET program is only evaluated once per tick; thus, if two cells depend on one I command, the user will only be prompted for input once.

SPREADSHEET has four data types, being the number, the string, the tuple (or complex number), and None:

Number: 10
Number: -10
Number: 10.5
NOT a Number: .5

String: "beans are cool!"
String: 'hello world'
NOT a string: "oops'
NOT a string: 'oops', i did it again'
String: 'yay,\' fixed now'

Tuple: (10,10)
Tuple: (1.3,-4)
Tuple: (1.963,100.37252)

None: None

Expressions and Operators

The following is a table of operators in SPREADSHEET. If some behaviour is not specified for this table, it returns None.

Operator	Arity	Function
+	2	Performs addition between numbers/tuples, and concatenation between strings.
-	2	Performs subtraction between numbers/tuples.
*	2	Performs scalar/complex multiplication between numbers/tuples, and scalar vector multiplication between a number and a tuple. Additionally, string number * returns string repeated number times, like in Python.
/	2	Performs divison between numbers/tuples, and scalar vector division between a number and a tuple.
#	1	Absolute value of numbers, component-wise absolute value of tuples, length of strings.
£	1	Sign of numbers, component-wise sign of tuples.
%	2	Modulus between numbers, component-wise modulus between tuples.
^	2	Exponentiation between numbers; complex-type exponentiation between numbers and tuples is encouraged in your implementation, but I was too lazy to implement it here.
?	3	A if C else B. For this statement, use Python truthiness rules. C is evaluated first, and then only the required argument is evaluated. This is needed for proper control flow.
=	2	Python ==. Returns 0 or 1.
<, >, ≤, ≥, =	2	Performs magnitude comparison. Takes in numbers, returns 0 or 1.
~	1	Shorthand for 1 x - on only numbers.
$	1	Returns the value of the cell at the input tuple; evaluates it if needed.
x, y	1	Gets x-coordinate or y-coordinate of the input tuple.
$	1	Returns the value of the cell at the input tuple; evaluates it if needed. If the cell has no value, it returns None.
C	2	Coerces the type of A to the type of B; see table below.
T	2	Builds a tuple from two numbers.
X	3	Python C[A:B] for strings.
@	0	Gets the coordinates of this cell.

Here is a table of values for the C operator:

From	To	Value
Number	Number	Self-explanatory.
Number	String	"<number>"
Number	Tuple	(<number>,<number>)
Number	None	None
String	Number	Parses string into a number, base 10.
String	String	Self-explanatory.
String	Tuple	Parses string into a tuple.
String	None	None
Tuple	Number	Gets the magnitude of the tuple.
Tuple	String	"<tuple>"
Tuple	Tuple	Self-explanatory.
Tuple	None	None
None	Number	0
None	String	"None"
None	Tuple	(0,0)
None	None	None

Examples

Here is a sample cat program:

I(0,1) //no equation
S(0,2): (0,0) <= (0,1) $

First, the S command evaluates. The first part of the S command is the position expression, which here is a single value and thus evaluates immediately. The second part of the command is the value expression, which here is a $ operator called on a tuple. This gets the value at (0,1), which has not been evaluated yet. Since this coordinate has an I command attached to it, it gets input from the user. When the user gives input, the command at (0,1) evaluates with a string. Then, since the value at (0,1) has evaluated, the S command at (0,2) evaluates. This sets the value at (0,0) to be whatever the user gave in. The program outputs what the user gave in, and then halts because no equations (apart from the one at (0,0), which is ignored) have changed.

Installing

Clone this repository or download SPREADSHEET.py directly.

Either run using Python (version 3):

python3 SPREADSHEET.py <rogram.sprd>

Or, ensure that the file is executable and in your PATH:

SPREADSHEET.py <program.sprd>