I have a prospective client that currently uses Miva Merchant as their e-commerce solution. They would like me to add functionality that I have done before with Magento. I know that Miva uses its own proprietary scripting language, but how similar is this to other languages? How steep is the learning curve to be able to modify core functionality of the shopping cart?
Are they're any resources out there to try developing for Miva without purchasing it?