Installation¶

Requirements¶

• Python 3.10 or higher (3.12+ recommended)
• pip (comes with Python)

Quick Install (Recommended)¶

Option A: pipx (Best for CLI tools)¶

pipx installs MOL in an isolated environment and makes the mol command available globally. This is the recommended method — it avoids permission errors and doesn't conflict with system Python.

sudo apt install pipx
pipx ensurepath
pipx install mol-lang

brew install pipx
pipx ensurepath
pipx install mol-lang

python -m pip install --user pipx
python -m pipx ensurepath
pipx install mol-lang

Option B: pip in a Virtual Environment¶

If you prefer pip, create a virtual environment first:

python3 -m venv mol-env
source mol-env/bin/activate
pip install mol-lang

python -m venv mol-env
mol-env\Scripts\Activate.ps1
pip install mol-lang

python -m venv mol-env
mol-env\Scripts\activate.bat
pip install mol-lang

Option C: System-wide pip (Not Recommended)¶

If you understand the risks and want to install globally anyway:

pip install mol-lang
# If blocked, use:
pip install --user mol-lang

Verify Installation¶

mol version
# MOL v2.0.2

If mol isn't found after installation:

# Check if it's in your PATH
which mol

# If using pipx, ensure PATH is set:
pipx ensurepath
# Then restart your terminal

# If using --user install, add to PATH:
export PATH="$HOME/.local/bin:$PATH"

# Check if mol is available
Get-Command mol

# If using pipx, ensure PATH is set:
python -m pipx ensurepath
# Then restart PowerShell

# If using --user install, add to PATH:
$env:PATH += ";$env:APPDATA\Python\Scripts"

Install from Source¶

# Clone the repository
git clone https://github.com/crux-ecosystem/mol-lang.git
cd mol-lang

# Create virtual environment
python -m venv .venv
source .venv/bin/activate  # Linux/macOS
# .venv\Scripts\activate   # Windows

# Install MOL
pip install -e .

VS Code Extension¶

MOL ships with a VS Code extension for syntax highlighting and snippets:

1. Open VS Code
2. Go to Extensions → ... → Install from VSIX
3. Or symlink the extension folder:

ln -s $(pwd)/mol-vscode ~/.vscode/extensions/mol-lang

Restart VS Code. All .mol files will have syntax highlighting automatically.

Dependencies¶

MOL has only one runtime dependency:

Development dependencies:

Updating¶

pip install --upgrade mol-lang