MSlash Script Interpreter

A lightweight Python-based interpreter for the MSlash scripting language — human-friendly syntax with variables, functions, classes, and modular imports.

---

✨ Features

Feature	Syntax Example	Notes
Variables	var name = "John"	Supports numbers, strings, lists, and Vata (dictionary) literals
String interpolation	say "Hello, ${name}!"	Works inside say, math, and assignments
Functions	func add(a,b) ... endfunc	Return values with return
Classes & Methods	class Foo ... func init(...) ... endclass	OOP-style with this
Imports (steal)	steal myFunc from utils.mslash	Imports from another .mslash file
Conditionals	if x > 5 ... else ... endif	Supports nesting
Loops	loop 3 ... endloop	Fixed-count loops
Math expressions	math 5 * (2 + 3)	Evaluates and prints result
Inline comments	{ comment }	Skipped during execution
User input	input username	Stores into a variable
Empty lines	emptyline 3	Prints blank lines
Pause execution	pause	Waits for Enter key
Terminate script	break	Ends execution immediately

---

📦 Installation

Requirements:

• Python 3.8+
• No external dependencies — pure Python.

Setup:

1. Save main.py in your project directory.
2. Create .mslash files for your scripts.
3. Run scripts with:

   python main.py your_script.mslash

If you rename main.py, just run:

python renamedmain.py your_script.mslash

---

▶️ Usage

Run:

python main.py your_script.mslash

Debug mode:

python main.py -d your_script.mslash

Without arguments:

python main.py

It will prompt:

Enter the name and file extension of the target file (e.g., demo.mslash):

---

📜 Language Reference

Variables

var name = "John"
var age = 30
say "Name: ${name}, Age: ${age}"

Functions

func greet(person)
    say "Hello, ${person}!"
endfunc

greet("Alice")

Classes

class Person
    func init(name, age)
        var this.name = name
        var this.age = age
    endfunc

    func introduce()
        say "I am ${this.name}, ${this.age} years old."
    endfunc
endclass

var p = new Person("Bob", 25)
p.introduce()

Conditionals

var num = 7
if num > 5
    say "Greater than 5"
else
    say "5 or less"
endif

Loops

loop 3
    say "Hello!"
endloop

Inline Comments

{ This is a comment }
var x = 42  { Comment after code }

String Interpolation

var name = "MSlash"
say "Hello, ${name}!"

User Input

input userName
say "Welcome, ${userName}!"

Math

math 3 * (4 + 5)

Empty Lines

emptyline 2
say "This appears after 2 blank lines."

Pause

say "Press enter to continue..."
pause

Break

say "Stopping now."
break

---

📦 Imports and Modularity

Use steal to import from another .mslash file.

utils.mslash

func multiply(a, b)
    return a * b
endfunc

func getGreeting()
    return "Hello from utils!"
endfunc

main.mslash

steal multiply from utils.mslash
steal getGreeting from utils.mslash

var product = multiply(6, 7)
say "6 * 7 = ${product}"
say "${getGreeting()}"

---

📊 Execution Flow Diagram

flowchart TD
    A[Start main.py] --> B[Read .mslash file]
    B --> C[Preprocess Script]
    C -->|Extract funcs/classes| D[Store in FUNCTIONS & CLASSES]
    C -->|Keep main code| E[Execute main code]
    E --> F[Parse line]
    F -->|Variable| G[Assign value]
    F -->|Function call| H[Execute function body]
    F -->|Class instantiation| I[Create MSlashObject]
    F -->|Import| J[Load module & merge symbols]
    F -->|Control flow| K[Run block or skip]
    F -->|Say| L[Print output]
    F -->|End of file| M[Program ends]

Loading

---

🧪 Quick Demo

utils.mslash

func multiply(a, b)
    return a * b
endfunc

func getGreeting()
    return "Hello from utils!"
endfunc

demo.mslash

var name = "World"
say "Hello, ${name}!"

func add(a, b)
    return a + b
endfunc

var result = add(5, 7)
say "5 + 7 = ${result}"

steal multiply from utils.mslash
steal getGreeting from utils.mslash

var product = multiply(3, 4)
say "3 * 4 = ${product}"
say "${getGreeting()}"

class Greeter
    func init(who)
        var this.target = who
    endfunc

    func greet()
        say "Greetings, ${this.target}!"
    endfunc
endclass

var g = new Greeter("MSlash User")
g.greet()

Run:

python main.py demo.mslash

Expected Output:

Hello, World!
5 + 7 = 12
3 * 4 = 12
Hello from utils!
Greetings, MSlash User!

---

💡 Best Practices

• Always close blocks (endif, endloop, endfunc, endclass).
• Keep steal imports at the top.
• Use this.var only inside methods.
• Comment generously with { }.

---

🛠 Developer Notes

To add new commands:

• Edit the execute() function in main.py.
• Add a new elif original_line.startswith("cmd ") block.

To add built-ins:

• Edit safe_eval()’s allowed_builtins dict.

---

📜 License

Copyright (c) 2025 Sahil Das

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software for commercial and non-commercial purposes, including without limitation
the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
sell copies of the Software, and to permit persons to whom the Software is furnished
to do so, subject to the following conditions:

1. Attribution is mandatory:
   All copies or substantial portions of the Software, whether in source or binary form, must include
   a clear attribution to the original author:
   "MSlash Script Interpreter by Sahil Das"

2. This permission notice shall be included in all copies or substantial portions of the Software.

3. The Software is provided "as is", without warranty of any kind, express or implied, including
   but not limited to the warranties of merchantability, fitness for a particular purpose and
   noninfringement. In no event shall the authors or copyright holders be liable for any claim,
   damages or other liability, whether in an action of contract, tort or otherwise, arising from,
   out of or in connection with the Software or the use or other dealings in the Software.