Optional type

Description

Instead of using pointers, ogen generates generic wrappers.

For example, OptNilString is string that is optional (no value) and can be null.

// OptNilString is optional nullable string.
type OptNilString struct {
    Value string
    Set   bool
    Null  bool
}

Multiple convenience helper methods and functions are generated, some of them:

// IsSet returns true if OptNilString was set.
func (o OptNilString) IsSet() bool
// Reset unsets value.
func (o *OptNilString) Reset()
// SetTo sets value to v.
func (o *OptNilString) SetTo(v string)
// IsSet returns true if value is Null.
func (o OptNilString) IsNull() bool
// Get returns value and boolean that denotes whether value was set.
func (o OptNilString) Get() (v string, ok bool)
// Or returns value if set, or given parameter if does not.
func (o OptNilString) Or(d string) string

func NewOptNilString(v string) OptNilString

Semantic

To implement decoder, ogen follows the rules below

Type

Schema	Type
required	T
optional	Opt[#T]
nullable, but required	Nil[#T]
optional & nullable	OptNil[#T]

Decoder behavior

Schema	no value	null	value
required	Error	Error	OK
optional	Set=false	Error	Set=true
nullable, but required	Error	Null=true	OK
optional & nullable	Set=false	Set=true,Null=true	Set=true,Null=false

Semantic for arrays

For arrays semantic is slightly different

Type

Schema	Type
required	[]T
optional	[]T
nullable, but required	[]T
optional & nullable	OptNil[#T]Array

Decoder behavior

Schema	no value	null	[]	non-empty array
required	Error	Error	Empty non-nil slice	Non-empty slice
optional	nil slice	Error	Empty non-nil slice	Non-empty slice
nullable, but required	Error	nil slice	Empty non-nil slice	Non-empty slice
optional & nullable	Set=false	Set=true,Null=true, empty slice	Set=true,Null=false, empty slice	Set=true,Null=false, non-empty slice