Global and nested functions, as introduced in Functions, are actually special cases of closures. Closures take one of three forms:
- Global functions are closures that have a name and do not capture any values.
- Nested functions are closures that have a name and can capture values from their enclosing function.
- Closure expressions are unnamed closures written in a lightweight syntax that can capture values from their surrounding context.
Swift’s closure expressions have a clean, clear style, with optimizations that encourage brief, clutter-free syntax in common scenarios. These optimizations include:
- Inferring parameter and return value types from context
- Implicit returns from single-expression closures
- Shorthand argument names
- Trailing closure syntax
This video was developed by Skip Wilson. You can follow him on Twitter (@SkipAllMighty).
