syxzyt/spl

Syxz Programming Language or SPL is a simple stack based programming language which I developed as a learning experience

SPL

Introduction

SPL is a scripting language developed as a first custom programming language project.

• It's syntax was mainly inspired from BASIC and X86.
• It does not feature any functions, but labels.
• Parameters can be achieved by pushing values onto a stack.

The compiler and virtual machine are all included into one visual studio solution. I developed it on Windows so I'm not 100% sure if the Linux code works, as I haven't been able to test it. As of right now, SPL has no way to code using multiple SPL files.

You can use the -d flag to disassemble any input the virtual machine is given You can use the -b flag to use breakpoints. See https://github.com/SYXZyt/SPL/blob/master/bytecode.md for help with breakpoints

Variables

Variables can be updated using the Let keyword. This keyword will tell the virtual machine that we are wanting to assign a value in memory. Variables in SPL can either be mutable or constant, which are created using let and const respectively. Constants are loaded into memory just before code execution begins, and cannot be changed once set. Constants can only store ints, floats or string. Copying a variable into a constant is impossible, as constants must be resolved at compile time. Variables only have three different types. Integer, Float or String. These are the three basic types and in SPL 1.0 there are no structs to create your own type.

Variables can be created using the following syntax

let [NAME] [VALUE]

Variables can not be defined as null. Variables can be created at compile time using the const keyword.

const PI 3.1415
free PI ;If this is deleted, it cannot be redefined as constant
const X PI  ;Since all variables are created at compile time, constants must be able to be parsed at compile time
;Currently, this does not allow const [NAME] [ANOTHER CONST NAME] but may be added in the future

Instructions

SPL features various instructions all with different functions. Many of these instructions use the stack, so it's important to understand what is on the stack and when.

Instruction	Description
print [literal or variable]	Print a literal or a variable to the console
println [literal or variable]	Print something to the string followed by a newline
let [identifier] [literal]	Create a value in memory
const [identifier [literal]]	Create a constant in memory
free	Free a variable and remove its value
goto [line_num or label_name]	Jump the current execution to a specific point in the code
call [label_name]	Jump the current execution to a specific point, while adding the current address to a call stack. Like calling a function. Unlike goto, call cannot jump to line numbers and must be given a label name
ret	Jump the current execution to a previous point which was stored in the callstack
exit [integer ]	Exit the program with a specific exit code
push [literal or variable]	Push a value onto the stack
pop	Pop a value off of the stack
setpop [identifier]	Create a value in memory, but using the a value off the stack
add	Add two values on the stack and push the result. Will throw error if non-numeric types
sub	Subtract two values on the stack and push the result. Will throw error if non-numeric types
mul	Multiply two values on the stack and push the result. Will throw error if non-numeric types
div	Divide two values on the stack and push the result. Will throw error if non-numeric types
pow	Calculate the power of a number on the stack and push the result. Will throw error if non-numeric types
concat	Add two values on the stack as a string, and push the result
to_float	Convert a value on the stack to a float. Will throw error if invalid
to_int	Convert a value on the stack to a int. Will throw error if invalid
to_string	Convert a value on the stack to a string
equ [line_num or label_name]	Check if the current two values on the stack are equal (==), and jump to the line or label if not
neq [line_num or label_name]	Check if the current two values on the stack are not equal (!=), and jump to the line or label if not
grt [line_num or label_name]	Check if the current two values on the stack are greater (>), and jump to the line or label if not
grtequ [line_num or label_name]	Check if the current two values on the stack are greater or equal (>=), and jump to the line or label if not
lwr [line_num or label_name]	Check if the current two values on the stack are lower (<), and jump to the line or label if not
lwrequ [line_num or label_name]	Check if the current two values on the stack are lower or equal (<=), and jump to the line or label if not
input	Get the users input, and store it to the stack
mod	Calculates the mod of two numbers
console setpos	Using two values on the stack (note x is pushed first), move the cursor to a set position
console clear	Clears all text on the screen
console setcolor	Using a value on the stack, set the foreground console colour. This is how colours are implemented. ConsoleAttributes
sleep [integer]	Sleep for a set amount of milliseconds
random [integer]	Pick a random number from 0 (inclusive) to the provided int (exclusive) and push the result to the stack
raise [value]	Throw a user error
is_int	Checks the current value, on the stack, can be converted to an integer, and pushes 1 onto the stack if it can be, 0 otherwise
is_float	Checks the current value, on the stack, can be converted to a floating point number, and pushes 1 onto the stack if it can be, 0 otherwise

It is very important that you remember to do all maths operations in reverse. Lets say you want to do 10 / 5, the SPL would be

push 5
push 10
div

Note that the right hand number is pushed first. This can be confusing at first and takes a little while to remember.

When moving the cursor, this is reversed with X being pushed first. So to move to x: 6, y: 2

push 6
push 2
console setpos

Future plans

SPL has reached end of life. No official updates are planned, unless to patch major bugs. If you wish to make any changes, feel free to do so. If deemed worthy, I'll happily accept a fork pull request.