dummy_patch.go

type Patch struct {
    // Implementation detail, should not be accessed
    from string
    to string
}

func NewPatch(from string, to string) *Patch {
    return &Patch { from, to }
}

func (patch *Patch) Apply(from string) string {
    if patch.from != from {
        panic("Patch applied incorrectly")
    }
    return patch.to
}