Teddy

Introduction

Teddy is a tiny programming language I built to understand how parsing and interpretation work behind the scenes. It is inspired from Chapter 12, Eloquent JS, Marijn Haverbeke; & Piyush Garg on YouTube.

The syntax of Teddy is designed to drive home a few key principles about the nature of programming. For instance, the assignment operator is not "=", but rather an arrow "->", which signals that bindings/variables actually point at values — not "contain" them. Also, vocabulary like "suppose" or "print" is a bit easier on the mind that "let" or "console.log".

What is Teddy?

Teddy is a humble program that demonstrates the fundamental concepts of:

• Lexical Analysis: We can break source code into tokens.
• Parsing: We can build an Abstract Syntax Tree (AST) from these tokens.
• Translation: We can convert this AST to JavaScript code.
• Interpretation: We can also execute this JS code.

Basic Syntax

This is how you write Teddy Code:

• Declaring Variables: suppose x -> 5;
• Arithmetic Operations: x + y, x - y, x * y, x / y
• Printing Values: print(x);
• Writing Comments: //This is a comment

Laws of this Language:

There are two types of 'values' in Teddy: Primitive & Non-Primitive.

Primitives are:

• Numbers: Integers. For instance: 10;
• Strings: Characters between two double-quote characters. For example: "str";
• Template Literals: Characters between two backtick characters. For example: `str ${expression}`;

Non-Primitives are:

• Arrays: An ordered collection of values. For example: [1,2,3];
• Objects: An unordered collection of key-value pairs. For instance: {name: "john", age: 21};

A few keywords to know about the language:

• suppose: Signals that a binding/variable is about to be declared
• if, elseIf, else: Control-flow statements that run code only when their conditions are true.
• function: Signals that a function is being declared & defined.

Some basic operators in language:

• Assignment: ->
• Arithmetic: +, -, *, /, %
• Logical: =, <, >, ==, !=, !==

Some basic functions in language:

• print(): The 'console.log()' in JS.
• All other JS functions are supported. Think of JS as a reliable proto language behind this one.

NOTE: As of now, some bad code would produce syntax-errors, & some would be ignored. This should get better as the language gets mature over time.