Making Origami expressions easier to learn and use

Over this summer I’ve shifted the Origami expression language to be a closer dialect of JavaScript expressions. Feedback from early adopters indicated that some differences from JavaScript created trouble; eliminating those would improve the language.

Origami is now essentially JavaScript expressions plus paths, with a few additional syntactic features that make it easier to define a site.

The language supports a conceptual model called Content/Transformation you may find helpful in thinking about how to build a site.

The syntax changes to the language included:

• Supporting standard JavaScript . syntax for accessing a property. This required developing a heuristic that could reliably tell that post.title is a property reference but image.jpg is a file name — even though both use the same period syntax.
• Consolidating Origami’s built-in functions into a small number of collections exposed as regular globals, like Tree for functions that work with trees and Origami for most everything else.
• Supporting JavaScript’s new syntax. I’d tried hard to avoid having reserved words, but new is so ingrained in JavaScript developers’ minds that any other syntax is hard to remember.

Origami is still missing some esoteric JavaScript expression features (e.g., function parameter destructuring), but those are all on the list tackle. The goal is that you should be able to copy any JavaScript expression and evaluate it as an Origami expression.

Why introduce an alternative expression language to JavaScript?

• Origami’s use of paths, including support for file extensions and its assumption that any expression might be async, lets you load or fetch files and get data out of them more concisely than with JavaScript. The resulting expression can be 20-40% shorter, making the intent of code easier to see.
• Expressions generally don’t have side effects, so restricting your code to expressions tends to keep you in the happy world of pure functions and immutable data — where things are much easier to reason about.
• With a few shorthands to accommodate a command line, Origami makes an excellent shell language, turning your OS terminal into a JavaScript console.

Watch the motion comic introducing the language, or walk through how to create a basic blog.