Principle: Progressive disclosure
Table of contents
Background
Progressive disclosure is a UX design pattern which defers revealing information and advanced/ special-case controls to the user until they are relevant to the current task, in order to make the system easier to learn and use. Although the term originates in GUI design, it can be applied to language design as well. In particular, it’s one of Swift’s core design principles.
Principle
In Carbon, we will prefer designs that support progressive disclosure, in the sense defined here:
… the idea that one can ignore certain aspects of the language when starting out, and then learn about them only at the time when you need them, without invalidating any of your prior understanding of the language.
Applications of this principle
Types such as i32 are designed to follow progressive disclosure: they are actually class types defined in the prelude library that support arithmetic operations by implementing certain customization interfaces. However, programmers can learn to use them by thinking of them as primitive types like their C counterparts, without needing to understand the arithmetic operator interfaces, interface implementation in general, libraries, the prelude, or even class types. Subsequently learning those concepts doesn’t invalidate that original mental model, but rather shows how that model is built out of more fundamental pieces.