moldo 0.3.1

A visual programming language that compiles to Python

Moldo

A visual programming language that compiles to Python, designed to make programming more accessible and intuitive.

Features

• XML-like syntax for easy visual representation
• Compiles to Python code
• Support for Python function imports
• Basic programming constructs (variables, functions, control flow)
• Built-in support for Python data types (strings, numbers, lists, dictionaries)
• Type safety and error handling
• Block-based loops with nested content

Installation

pip install moldo

Quick Start

1. Create a .moldo file with your code:

<mblock type="print">Hello, World!</mblock>

<mblock type="input">What's your name? </mblock>
<mblock type="variable">name = input()</mblock>
<mblock type="print">f"Nice to meet you, {name}!"</mblock>

2. Compile and run:

moldo compile your_file.moldo -o output.py
python output.py

Loop Structures

Moldo supports two different loop syntax options:

1. Simple Loop Syntax (Legacy)

<mblock type="loop">i in range(5)</mblock>
    <mblock type="print">i</mblock>

2. Block-Based Loop Syntax (Recommended)

<mblock type="loop" condition="i in range(5)">
    <mblock type="print">f"Current value: {i}"</mblock>
    <mblock type="variable">squared = i * i</mblock>
    <mblock type="print">f"Squared: {squared}"</mblock>
</mblock>

Simple Counter Example (1 to 6)

<!-- A simple counter that counts from 1 to 6 -->
<mblock type="print">Counting from 1 to 6:</mblock>
<mblock type="loop" condition="count in range(1, 7)">
    <mblock type="print">f"Number: {count}"</mblock>
</mblock>

The block-based syntax (with the condition attribute) is recommended as it:

• Properly supports nested content
• Maintains clear scope boundaries
• Provides better visual representation of the code structure
• Results in more readable generated Python code

Examples

Counter Example

<mblock type="print">Simple Counter Example</mblock>

<!-- Counter initialization -->
<mblock type="variable">counter = 0</mblock>

<!-- Print header -->
<mblock type="print">Counting from 1 to 10:</mblock>

<!-- Counter for loop using block-based syntax -->
<mblock type="loop" condition="i in range(1, 11)">
    <mblock type="print">f"Count: {i}"</mblock>
    <mblock type="variable">counter += i</mblock>
</mblock>

<!-- Print final counter value -->
<mblock type="print">f"Sum of numbers 1-10: {counter}"</mblock>

Dictionary Operations Example

<!-- Create a dictionary -->
<mblock type="variable">student = {"name": "Alice", "age": 20, "grades": [85, 90, 95]}</mblock>

<!-- Access dictionary values -->
<mblock type="variable">name = student["name"]</mblock>
<mblock type="print">name</mblock>

<!-- Add or modify dictionary entries -->
<mblock type="variable">student["subject"] = "Computer Science"</mblock>

<!-- Print the entire dictionary -->
<mblock type="print">student</mblock>

<!-- Loop through dictionary keys and values -->
<mblock type="loop" condition="key in student">
    <mblock type="variable">value = student[key]</mblock>
    <mblock type="print">f"{key}: {value}"</mblock>
</mblock>

Calculator Example

<!-- Import the math functions module -->
<mblock type="import">examples/math_functions.py</mblock>

<!-- Get input from user -->
<mblock type="input">Enter first number: </mblock>
<mblock type="variable">num1 = float(input())</mblock>

<mblock type="input">Enter second number: </mblock>
<mblock type="variable">num2 = float(input())</mblock>

<!-- Perform calculations -->
<mblock type="print">Addition: </mblock>
<mblock type="call">add(num1, num2)</mblock>

<mblock type="print">Subtraction: </mblock>
<mblock type="call">subtract(num1, num2)</mblock>

<mblock type="print">Multiplication: </mblock>
<mblock type="call">multiply(num1, num2)</mblock>

<mblock type="print">Division: </mblock>
<mblock type="call">divide(num1, num2)</mblock>

Temperature Converter Example

<mblock type="import">examples/temperature_utils.py</mblock>

<mblock type="print">Welcome to Temperature Converter!</mblock>
<mblock type="print">1. Convert Celsius to Fahrenheit</mblock>
<mblock type="print">2. Convert Fahrenheit to Celsius</mblock>

<mblock type="input">Enter your choice (1 or 2): </mblock>
<mblock type="variable">choice = input()</mblock>

<mblock type="variable">
if choice == "1":
    print("Enter temperature in Celsius: ", end="")
    celsius = float(input())
    print(f"{celsius}°C is equal to ", end="")
    result = temperature_utils.celsius_to_fahrenheit(celsius)
    print(f"{result:.1f}°F")
elif choice == "2":
    print("Enter temperature in Fahrenheit: ", end="")
    fahrenheit = float(input())
    print(f"{fahrenheit}°F is equal to ", end="")
    result = temperature_utils.fahrenheit_to_celsius(fahrenheit)
    print(f"{result:.1f}°C")
else:
    print("Invalid choice! Please enter 1 or 2.")
</mblock>

Creating Custom Functions

To create functions that can be used in Moldo, use the @moldo_function decorator:

from moldo.decorators import moldo_function

@moldo_function(reference_name="add")
def add_numbers(a: float, b: float) -> float:
    """Add two numbers together."""
    return a + b

sample snippet

{
  "code": "<mblock type=\"print\">Hello, World!</mblock>",
  "python_modules": {

  }
}

Command Line Interface

The moldo command provides several options:

moldo compile <input_file> -o <output_file>  # Compile Moldo code to Python
moldo run <input_file>                       # Compile and run Moldo code
moldo --help                                 # Show help message

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

License

This project is licensed under the MIT License - see the LICENSE file for details.

Author

• Mutiibwa Grace Peter - GitHub

Acknowledgments

• ANTLR4 for the parsing infrastructure
• Python community for inspiration and tools