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Overview ¶
Package optional is a generic take on [functional options](https://dave.cheney.net/2014/10/17/functional-options-for-friendly-apis).
Index ¶
Constants ¶
const ErrDecode errs.Const = "optional: decode configuration"
ErrDecode reports that a Configuration could not be decoded into the target struct; it wraps the underlying mapstructure failure. It is a const of errs.Const so callers can match it with errors.Is.
Variables ¶
This section is empty.
Functions ¶
func Decode ¶
func Decode[T any](in Configuration) (*T, error)
Decode turns the Configuration map into a struct for you.
func NewWithDefault ¶
NewWithDefault returns a T that starts from a default T and then has all the options folded on top, skipping any nil options.
Types ¶
type Configuration ¶
Configuration is a nice general-purpose configurable map.
func NewConfiguration ¶
func NewConfiguration(opts ...Option[Configuration]) Configuration
NewConfiguration whips up a Configuration from whatever options you pass in.
type ConfigurationKey ¶
ConfigurationKey is a typed key for a value living in a Configuration.
func (ConfigurationKey[T]) Opt ¶
func (o ConfigurationKey[T]) Opt(v T) Opt[T]
Opt builds an Opt for this key, wrapping up the value you give it.
type Map ¶
type Map[K comparable, V any] map[K]V
Map is an even more general configurable map than a Configuration is.
type Opt ¶
Opt is a single Configuration option, ready to apply.
func Enabled ¶
func Enabled(o ConfigurationKey[bool]) Opt[bool]
Enabled builds a bool Opt for this key and flips it on (true).
func KV ¶
func KV[T any](k ConfigurationKey[T], v T) Opt[T]
KV is a quick little helper for spinning up an Opt option.
func (Opt[T]) Apply ¶
func (c Opt[T]) Apply(t Configuration) Configuration
Apply is how Opt satisfies the Option interface: it returns the Configuration with the option set, allocating the map first when it's nil.
type Option ¶
type Option[T any] interface { Apply(T) T }
Option is the interface for any type that knows how to apply its field values onto a T: Apply receives the value being built and returns the updated value. Options are value transformers — a T is built by folding options over a starting value, never through a pointer.
type Pair ¶
type Pair[K comparable, V any] struct { Key K Value V }
Pair is a single Map option, ready to apply.
Source Files