Simple Interpreter with Dart

This repository contains a basic interpreter written in Dart. It includes a lexer, parser, and interpreter capable of handling simple arithmetic expressions, variable declarations, and print statements.

Features

• Tokenizes input using a lexer.
• Parses expressions, including:
  • Arithmetic operations: +, -, *, /
  • String literals
  • Variable declarations (var keyword)
  • Print statements (print keyword)
• Supports basic syntax validation.

Usage

Running the Interpreter

The interpreter expects a .dse file as input. You can run the interpreter using the following command:

dart run bin/interpreter_app.dart

Place your .dse file in the appropriate path (as defined in Paths.appPath) and ensure the file has valid syntax. The interpreter will read the file, tokenize the content, parse the tokens, and execute the resulting commands.

Example Code (app.dse)

var x = 10;
var y = 20;
print x + y;
print "Hello, World!";

Sample Output

Running interpreter for file: app.dse
30
Hello, World!
finished in 0.004s

Project Structure

• core/lexer.dart: Contains the Lexer class responsible for tokenizing the source code.
• core/parser.dart: Contains the Parser class, which handles the parsing and interpreting of tokens.
• lib/main.dart: Main entry point for running the interpreter.
• constants/path.dart: Provides file path constants.

Supported Tokens

Token	Description
number	Integer literals
plus	+ operator
minus	- operator
star	* operator
slash	/ operator
print	Print statement
identifier	Variable names
eof	End of file
qmark	Question mark (not used)
string	String literals
variable	var keyword
equals	= assignment operator
semicolon	; statement terminator
comment	Comments (// style)

Functions

The interpreter supports simple function definitions and invocations.

Example:

func testFunc = (a, b) {
  print a;
  print b;
};

testFunc(5, 3);

In this example, the function testFunc takes two arguments, a and b, and print their one by one.

Supported Features:

• Function definition using the func keyword.
• Parameterized function calls.

Requirements

• Dart SDK

Install the Dart SDK by following the instructions at https://dart.dev/get-dart.

How to Contribute

Feel free to fork this repository and submit pull requests. Contributions, such as improvements to the interpreter, additional features, or bug fixes, are welcome.

How to Run Tests

There are currently no automated tests, but you can test the interpreter by writing .dse files and running them with the interpreter.

License

This project is licensed under the Apache License 2.0. See the LICENSE file for details.

Repository

The repository is hosted on GitHub. Clone it or explore the code here.