github.com/l3x/learn-fp-go@v0.0.0-20171228022418-7639825d0b71/2-design-patterns/ch04-solid/02_maybe/src/maybe/option.go (about)

     1  package maybe
     2  
     3  type Option interface {
     4  	Empty() bool
     5  }
     6  
     7  func None() Option {
     8  	return emptyOption{}
     9  }
    10  
    11  type emptyOption struct{}
    12  
    13  func (e emptyOption) Empty() bool { return true }
    14  
    15  func (e emptyOption) String() string {
    16  	return "<EMPTY>"
    17  }
    18