Swift Style

Styling Colinear Braces

The Rule of Joshua (courtesy of Joshua Weinberg, an Apple engineer who first introduced me to this style) requires space padding in colinear (single-line) bracing, as in the following example:

if x > y {return z} // no
if x > y { return z } // yes

Adopting this rule allows single-line clauses to breathe. They add visual whitespace that helps move the embedded statement or statements away from the control structure that surrounds them. Limit single-line clauses to statements that are quick and uncomplicated.

It’s most common to use single-line clauses when chaining functions. In the following example, single-line scopes are passed to chained filter and map functions. The first selects items that are divisible ...