cast

cast

This project adheres to Semantic Versioning. This package is considered mature, you should expect package stability in Minor and Patch version releases

• Major: backwards incompatible package updates
• Minor: feature additions
• Patch: bug fixes, backward compatible model and function changes, etc.

CHANGELOG

cast is forked from spf13/cast.

What is Cast?

Cast is a library to convert between different go types in a consistent and easy way.

Cast provides simple functions to easily convert a number to a string, an interface into a bool, etc. Cast does this intelligently when an obvious conversion is possible. It doesn’t make any attempts to guess what you meant, for example you can only convert a string to an int when it is a string representation of an int such as “8”. Cast was developed for use in Hugo, a website engine which uses YAML, TOML or JSON for meta data.

Why use Cast?

When working with dynamic data in Go you often need to cast or convert the data from one type into another. Cast goes beyond just using type assertion (though it uses that when possible) to provide a very straightforward and convenient library.

If you are working with interfaces to handle things like dynamic content you’ll need an easy way to convert an interface into a given type. This is the library for you.

If you are taking in data from YAML, TOML or JSON or other formats which lack full types, then Cast is the library for you.

Usage

Cast provides a handful of To<Type> methods. These methods will always return the desired type. If input is provided that will not convert to that type, the 0 or nil value for that type will be returned. In order to differentiate between success and the nil value a set of To<Type>E methods are provided that return both the cast value and any error that occurrs.

Examples

cast.ToString("mayonegg")         // "mayonegg"
cast.ToString(8)                  // "8"
cast.ToString(8.31)               // "8.31"
cast.ToString([]byte("one time")) // "one time"
cast.ToString(nil)                // ""

var foo interface{} = "one more time"
cast.ToString(foo)                // "one more time"

intVal := cast.ToInt(8)           // 8
intVal := cast.ToInt(8.31)        // 8
intVal := cast.ToInt("8")         // 8
intVal := cast.ToInt(true)        // 1
intVal := cast.ToInt(false)       // 0

var eight interface{} = 8
intVal := cast.ToInt(eight)         // 8
intVal := cast.ToInt(nil)           // 0

intVal := cast.ToInt("Hi!")         // 0
intVal, err := cast.ToIntE("Hi!")   // 0, unable to cast "Hi!" of type string to int