Decorator chaining for Go.
Deco is a lightweight, generic Go package designed to facilitate the chaining of decorators, providing a simple yet powerful API for enhancing or modifying behavior in a composable manner. By reducing chains to a single function (a new decorator), Deco ensures that these chains become immutable and therefore thread-safe, making it ideal for applications requiring high concurrency or immutable data patterns. Whether for HTTP middleware, logging, data processing, or other processing layers, Deco offers a clean and flexible solution.
- Generic: works with any data type, providing flexibility across different use cases.
- Chaining: easily chain multiple decorators together to build complex processing pipelines.
- Extendibility: dynamically extend existing chains with additional decorators.
- Simplicity: minimal and straightforward API that's easy to integrate and use within your projects.
go get github.com/vilarfg/go-decoimport (
"github.com/vilarfg/go-deco"
"strings"
)
func stop(s string) string { return s + ". Stop it." }
func name(s string) string { return "Ford, " + s }
func turning(s string) string { return "you're turning into " + s }
func uppercase(s string) string { return strings.ToUpper(s) }
func identity(s string) string { return s }
// An empty chain produces a decorator
// that does not decorate at all.
// Internally is the identity function.
var chain0 = deco.Chain[string]()
// A chain of one or more decorators produces a new decorator.
// Decorators are applied in reverse order,
// `name` will be applied before `stop`.
// Notice how the type of the thing being decorated is inferred.
var chain1 = deco.Chain(stop, name)
// Decorators can be extended to produce a new decorator.
// `turning` will be applied before the original decorator.
var chain2 = chain1.Extend(turning)
// Which, in turn, can be further extended.
var chain3 = chain2.Extend(uppercase)
// nil values are filtered out
var chain4 = chain3.Extend(nil, identity)
println(chain0("whale")) // "whale"
println(chain1("bowl of petunias")) // "Ford, bowl of petunias. Stop it."
println(chain2("a sofa")) // "Ford, you're turning into a sofa. Stop it."
println(chain3("yarn")) // "Ford, you're turning into YARN. Stop it."
println(chain4("a penguin")) // "Ford, you're turning into A PENGUIN. Stop it.func Chain[T any](decorators ...Decorator[T]) Decorator[T]- Chains multiple decorators into a single decorator.
- Decorators are applied in reverse order
type Decorator[T any] func(T) T- A function that takes a value of type
Tand returns a potentially modified value of the same type.
- A function that takes a value of type
func (m Decorator[T]) Extend(decorators ...Decorator[T]) Decorator[T]- Extends an existing decorator with additional decorators.
- Decorators are applied in reverse order
func (m Decorator[T]) Apply(t T) T- Applies the decorator to a value.
MIT. Copyright © 2024 Fernando G. Vilar.