Simple Language Compiler

A basic programming language and compiler built in Python.

Language Features

• Data Types:
  • Integers
  • Floating-point numbers
  • Strings (with interpolation)
  • Booleans
• Operators:
  • Arithmetic: +, -, *, /
  • Comparison: ==, !=, <, >, <=, >=
  • Logical: !, &&, ||
• Control flow (if/else, while loops)
• Variables and assignments
• Print statement
• Single-line and multi-line comments
• String interpolation with ${expression} syntax

Execution Modes

This compiler supports two execution modes:

1. AST Interpretation - Directly interprets the abstract syntax tree
2. Bytecode Compilation - Compiles to bytecode and runs on a virtual machine (faster)

Syntax

Variable Declaration

var name = value;

Assignment

name = value;

Print Statement

print expression;

If Statement

if (condition) {
    statements;
} else {
    statements;
}

While Loop

while (condition) {
    statements;
}

Compound Statements

{
    statement1;
    statement2;
    ...
}

Comments

// Single-line comment

/* 
   Multi-line
   comment
*/

Data Types

// Integers
var a = 42;

// Floating-point numbers
var pi = 3.14159;

// Strings
var greeting = "Hello, World!";

// Booleans
var isTrue = true;
var isFalse = false;

String Interpolation

var name = "World";
print "Hello, ${name}!";  // Outputs: Hello, World!

var a = 10;
var b = 20;
print "The sum of ${a} and ${b} is ${a + b}";  // Outputs: The sum of 10 and 20 is 30

// Complex expressions are supported
var x = 5;
print "The square of ${x} is ${x * x}";  // Outputs: The square of 5 is 25

Operators

// Arithmetic operators
var sum = a + b;
var difference = a - b;
var product = a * b;
var quotient = a / b;

// Comparison operators
var isEqual = a == b;
var isNotEqual = a != b;
var isLess = a < b;
var isGreater = a > b;
var isLessOrEqual = a <= b;
var isGreaterOrEqual = a >= b;

// Logical operators
var not = !isTrue;
var and = isTrue && isTrue;
var or = isTrue || isFalse;

Running a Program

Run with bytecode compilation (default and faster):

python run.py examples/sample.txt

Run with AST interpretation:

python run.py examples/sample.txt --interpret

Debug bytecode:

python run.py examples/sample.txt --bytecode --debug

Example Programs

Several example programs are included in the examples/ directory to demonstrate language features:

• arithmetic.txt - Basic arithmetic operations
• strings.txt - String manipulation
• conditionals.txt - If/else statements
• loops.txt - While loops
• fizzbuzz.txt - Classic FizzBuzz problem
• primes.txt - Find prime numbers
• data_types.txt - Demonstrate boolean and float types
• string_interpolation.txt - Examples of string interpolation

Bytecode Compilation

The bytecode compiler translates the AST into a sequence of stack-based instructions that can be executed by the virtual machine. This provides:

1. Better performance - Bytecode execution is faster than AST interpretation
2. Smaller memory footprint - Bytecode is more compact than the AST
3. Potential for optimization - Bytecode can be optimized before execution

The bytecode includes:

• Operation codes (opcodes) for each instruction
• A constants pool for literals (numbers, strings)
• Variable storage indexed by name