NITLang — Educational Programming Language & Virtual Machine

NITLang is a small educational programming language developed as part of the Programming Language Design course.
It evolves step-by-step from arithmetic expressions to recursion, scoping, references, types, objects, lambdas, and a virtual machine backend.

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📁 Project Structure

AST.py
Tokenizer.py
Parser.py
SemanticAnalysis.py
CodeGenerator.py
tsvm.py
test.txt
README.md

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🧠 Compiler Architecture (Mermaid Diagram)

flowchart LR
    A[Source Code TXT] --> B[Lexer Tokenizer]
    B --> C[Parser]
    C --> D[AST Tree]
    D --> E[Semantic Analysis]
    E --> F[Code Generator]
    F --> G[TSVM Assembly]
    G --> H[TSVM Virtual Machine]

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1. Abstract Syntax Tree (AST)

All node types that define the structure of NITLang programs are implemented in
AST.py.

Includes node classes for:

• Program, Functions, Classes
• Binary / Unary operations
• Assignments, Variables
• If / While / Block statements
• Vectors, Indexing
• Object creation, Methods, Field access
• Lambda nodes

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2. Tokenizer (Lexer)

Implemented in Tokenizer.py using PLY.

Supports:

• Keywords: let, func, class, if, while, ref, lambda, map, …
• Operators: + - * / == != <= >= := -> && ||
• Literals: integers, strings, booleans, multi-line strings
• Comments: single-line and nested

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3. Parser (Grammar & Syntax)

Implemented in Parser.py.

Builds the AST using PLY YACC.
The parser handles:

• Expressions
• Conditionals / Loops
• Functions & recursion
• Types
• Classes & objects
• Lambdas
• Vectors

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🏛 Semantic Analysis

Implemented in SemanticAnalysis.py.

Checks:

• Type correctness
• Scope (global, local, params)
• Object field rules (private, must use this)
• Lambda typing
• Reference rules (ref, :=)

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⚙ Code Generator

Implemented in CodeGenerator.py.

Produces stack-based TSVM assembly.
Handles:

• Arithmetic, logic, comparisons
• Stack frames & calling conventions
• Methods & constructors
• Object layout (field offsets)
• Vectors & indexing
• References
• Memory allocation

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🖥 TSVM Virtual Machine

Implemented in tsvm.py.

Supports:

• Registers (r0, r1, …, fp, sp)
• Stack (0–9000), Globals (10000+), Heap (20000+)
• Instructions:
  mov, ld, st, add, sub, mul, div,
  cmp, push, pop, br, bz, bnz, call, ret

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▶ How to Run

1️⃣ Install dependencies

pip install ply

2️⃣ Compile a NITLang program

python Parser.py

Output:
✔ Semantic validation
✔ Generated assembly → output.tsvm

3️⃣ Run on the Virtual Machine

python tsvm.py output.tsvm

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🚀 Full Pipeline (Mermaid Diagram)

flowchart TB
    subgraph Compiler
        L[Lexer] --> P[Parser]
        P --> AST[AST Tree]
        AST --> S[Semantic Analyzer]
        S --> CG[Code Generator]
    end

    subgraph Runtime
        CG --> ASM[output.tsvm]
        ASM --> VM[TSVM Virtual Machine]
    end

    VM --> OUT[Program Output]

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📌 Example Program (test.txt)

Covers all features:

• Arithmetic
• Recursion (fact)
• Scope
• References
• Types
• Classes & methods
• Lambdas & map