Custom Programming Language Documentation

Overview

This custom programming language is a small, interpreted language built from scratch using Python. (took me 50+ hours)

The language uses core compiler/interpreter concepts including lexical analysis, parsing, and interpretation.

Language Processing Pipeline

Source Code

Lexer

Parser

Interpreter

Output

Language Syntax

Basic Syntax Rules

Element	Syntax	Description
Comments	`# This is a comment`	Single line comments using the # symbol
Integer Declaration	`age = int(15)`	Declare and initialize an integer variable
String Declaration	`name = string("Jim")`	Declare and initialize a string variable
Output Statement	`say("Hello World")`	Print text or variable values to output
Variable Output	`say(variableName)`	Print the value of a variable
Repeat Block	`repeat 3 { say("hi") }`	Repeat the statements inside the braces a specified number of times
Arithmetic Operators	`+, -, *, /`	Supports arithmetic in expressions and assignments
If Statement	`if x > 5 { say("x is greater than 5") }`	Conditionally execute statements if the condition is true
Function Definition	`function name { say("Hello") }`	Define a reusable block of code with a name
Function Call	`call(name)`	Execute a previously defined function

Code Examples

Hello World Program

  # My first program in the custom language
  
  say("Hello, World!")

Variable Declaration and Usage

# Declare variables

age =  int(16)

name =  string("Alice")

# Output variables

say(name)

say(age)

Repeat Block Demo

# Repeat a statement multiple times

repeat 4 {

  say("hello!")

}

Arithmetic Operators Demo

# Calculate minutes in a day

minutes_in_a_day =  int(60 * 24)

say(minutes_in_a_day)

# More complex expression

result =  int((2 + 3) * 4 - 6 / 2)

say(result)

If Statement Demo

# If statement demo

minutes =  int(60 * 24)

if minutes > 100 {

  say("there are more than 100 minutes in a day!")

}

# If with equality

x =  int(5)

if x == 5 {

  say("x is five!")

}

Function Demo

# Define a simple function

function hello {

  say("Hello, World!")

}

# Call the function

call(hello)

# Function with multiple statements

function greet {

  name = string("Alice")

  say(name)

  say("Welcome to our language!")

}

call(greet)

Technical Architecture

Lexer (Tokenizer)

Reads the code and splits it into pieces called tokens, like words and symbols.

Parser

Uses these tokens to build a tree that shows the program's structure.

Interpreter

Walks through the tree and runs the program step-by-step.

Symbol Table

Keeps track of variables, functions, their types, and current values while the program runs.

Token Types

The lexer recognizes the following token types:

Keywords: int, string, function, call
Identifiers: Variable names, function names
Literals: String literals, integer literals
Operators: Assignment (=), arithmetic operators (+, -, *, /), comparison operators (==, !=, >, <, >=, <=)
Delimiters: Parentheses, braces, quotes
Functions: say
Comments: Lines starting with #

Getting Started

Requirements

This project requires NO pip imports!

To run programs in this custom language, you need:

Python 3.6 or higher installed on your system
The github repository cloned
A text editor to write your programs

Running Your First Program

Follow these steps to create and run your first program:

# 1. Create a new file with .txt extension (e.g., hello.txt)

# 2. Write your program:

say("Hello from my custom language!")

# 3. Run using the python file:

# python run.py hello.txt

Debug Mode

Enable debug mode to see how your program is processed:

Mady with love by Jim