Option go lang implementation
A container struct which may not contain a non-null value. If a value is present, IsPresent() will return true and Get() will return the value. Additional methods that depend on the presence or absence of a contained value are provided, such as OrElse() (return a default value if value not present).
Returns an empty Option instance. No value is present for this Option. Returns:
an empty Option
usage:
emptyOption := option.empty()Returns an Option with the specified present non-null value.
Returns:
an Optional with the value present
usage:
optionInstance := option.Of("test")If a value is present in this Option, returns the value, otherwise return None
Returns:
the non-null value held by this Option
usage:
optionInstance := option.Of("test")
optionValue := optionInstance.Get()Return true if there is a value present, otherwise false.
Returns:
true if there is a value present, otherwise false
usage:
optionInstance := option.Of("test")
isPresent := optionInstance.IsPresent()Return the value if present, otherwise return other.
Returns:
Return the value if present, otherwise return other.
usage:
emptyOption := option.empty()
optionValue := optionInstance.OrElse("myDefaultValue")Return the contained value, if present, otherwise returns error
Returns:
Return the contained value, if present, otherwise returns error
usage:
emptyOption := option.empty()
err := optionInstance.OrElseError(errors.New("My custom error"))or
optionInstance := option.Of("test")
value := optionInstance.OrElseError(errors.New("My custom error"))Returns this option if present and math with the given predicate, otherwise returns None
There are some predicates available. Have a look file option/predicates.go but you could develop your own ones. Just follow this signature
type Predicate func(interface{}) bool
Returns:
Returns this option if present and math with the given predicate, otherwise returns None
usage:
option := Of(1)
optionValue := optionInstance.Filter(equalInt(1))Note: equalInt is a predefined predicate created as an example of how to use the type Predicate type Predicate func(interface{}) bool. You could have a look how is implemented and develop your own predicates for your custom struts.
Returns this option if present and not math with the given predicate, otherwise returns None
There are some predicates available. Have a look file option/predicates.go but you could develop your own ones. Just follow this signature
type Predicate func(interface{}) bool
- Input interface represents the option value.
- output bool represents if there are a value that match with the given inputValue
Returns:
Returns this option if present and not math with the given predicate, otherwise returns None
usage:
option := Of(2)
optionValue := optionInstance.FilterNot(equalInt(1))Note: equalInt is a predefined predicate created as an example of how to use the type Predicate type Predicate func(interface{}) bool. You could have a look how is implemented and develop your own predicates for your custom struts.
Finds elements of an array satisfying a finder function. If any element match with the given function then returns None.
There are some finders available. Have a look file option/finders.go but you could develop your own ones. Just follow this signature
type Finder func(interface{}) (bool, interface{})
- Input interface represents the option value.
- output bool represents if there are a value that match with the given inputValue
- output interface represents the value or values that match with the inputValue
Returns:
Returns this option or a slice of this option if present and math with the given finder function, otherwise returns None
usage:
option := Of([]int{2, 3, 5, 7, 11, 13})
result := option.Find(FindElemIntArrayGreaterThan(5))Note: FindElemIntArrayGreaterThan is a predefined finder created as an example of how to use the type finder type Finder func(interface{}) (bool, interface{}). You could have a look how is implemented and develop your own finders for your custom struts.
apply a f action function to option value.
There are some actions function available. Have a look file option/actions.go but you could develop your own ones. Just follow this signature
type Action func(interface{}) (err error, result interface{})
- Input interface represents the option value.
- output error represents if there are any error in the mapping action
- output interface represents the option value mapped
Returns:
Returns input interface (option.value) mapped by an action function
usage:
option := Of([]string{"madrid", "toledo"})
option.Map(UpperCaseArrayString())
result := option.Get()Note: UpperCaseString is a predefined action created as an example of how to use the type action type Action func(interface{}) (err error, result interface{}). You could have a look how is implemented and develop your own actions for your custom struts.