Documentation
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Overview ¶
Package reflectx provides a collection of helpers for the reflect package in the Go standard library.
Index ¶
- func AnyIsNil(v any) bool
- func CloneToType(typ reflect.Type, val any) reflect.Value
- func CopyMapRobust(to, from any) error
- func CopySliceRobust(to, from any) error
- func FormatDefault(def string) string
- func KindIsBasic(vk reflect.Kind) bool
- func LongTypeName(typ reflect.Type) string
- func MapAdd(mv any)
- func MapDelete(mv any, key reflect.Value)
- func MapDeleteAll(mv any)
- func MapKeyType(mp any) reflect.Type
- func MapSort(mp any, byKey, ascending bool) []reflect.Value
- func MapValueSort(mpvnp reflect.Value, keys []reflect.Value, ascending bool) error
- func MapValueType(mp any) reflect.Type
- func NewFrom(v reflect.Value) reflect.Value
- func NonDefaultFields(v any) map[string]any
- func NonPointerType(typ reflect.Type) reflect.Type
- func NonPointerValue(v reflect.Value) reflect.Value
- func NumAllFields(parent reflect.Value) int
- func OnePointerValue(v reflect.Value) reflect.Value
- func PointerValue(v reflect.Value) reflect.Value
- func SetFromDefaultTag(v reflect.Value, def string) error
- func SetFromDefaultTags(v any) error
- func SetMapRobust(mp, ky, val reflect.Value) bool
- func SetRobust(to, from any) error
- func ShortTypeName(typ reflect.Type) string
- func SliceDeleteAt(sl any, idx int)
- func SliceElementType(sl any) reflect.Type
- func SliceElementValue(sl any) reflect.Value
- func SliceNewAt(sl any, idx int)
- func SliceSort(sl any, ascending bool) error
- func StringJSON(v any) string
- func StructSliceSort(structSlice any, fieldIndex []int, ascending bool) error
- func StructTags(tags reflect.StructTag) map[string]string
- func ToBool(v any) (bool, error)
- func ToFloat(v any) (float64, error)
- func ToFloat32(v any) (float32, error)
- func ToInt(v any) (int64, error)
- func ToString(v any) string
- func ToStringPrec(v any, prec int) string
- func Underlying(v reflect.Value) reflect.Value
- func UnderlyingPointer(v reflect.Value) reflect.Value
- func ValueIsDefault(fv reflect.Value, def string) bool
- func ValueSliceSort(sl []reflect.Value, ascending bool) error
- func WalkFields(parent reflect.Value, ...)
- type SetAnyer
- type SetColorer
- type SetStringer
- type ShouldSaver
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func AnyIsNil ¶
AnyIsNil checks if an interface value is nil. The interface itself could be nil, or the value pointed to by the interface could be nil. This safely checks both.
func CloneToType ¶
CloneToType creates a new pointer to the given type and uses SetRobust to copy an existing value (of potentially another type) to it.
func CopySliceRobust ¶
CopySliceRobust robustly copies slices.
func FormatDefault ¶
FormatDefault converts the given `default:` struct tag string into a format suitable for being used as a value in SetRobust. If it returns "", the default value should not be used.
func KindIsBasic ¶
KindIsBasic returns whether the given reflect.Kind is a basic, elemental type such as Int, Float, etc.
func LongTypeName ¶
LongTypeName returns the long, full package-path qualified type name. This is guaranteed to be unique and used for internal storage of several maps to avoid any conflicts. It is also very quick to compute.
func MapKeyType ¶
MapKeyType returns the type of the key for the given map (which can be a pointer to a map or a direct map); just Key() of map type, but using this function makes it more explicit what is going on.
func MapSort ¶
MapSort sorts the keys of the map either by key or by value, and returns those keys as a slice of [reflect.Value]s.
func MapValueSort ¶
MapValueSort sorts the keys of the given map by their values.
func MapValueType ¶
MapValueType returns the type of the value for the given map (which can be a pointer to a map or a direct map); just Elem() of map type, but using this function makes it more explicit what is going on.
func NewFrom ¶ added in v0.2.0
NewFrom returns a value that is guaranteed to be a pointer to the Underlying version of the given value. If that value is not addressable, it makes a new fake pointer that points to a copy of the value, not the actual value. This should only be used you do not need the pointer to actually point to the original value.
func NonDefaultFields ¶
NonDefaultFields returns a map representing all of the fields of the given struct (or pointer to a struct) that have values different than their default values as specified by the `default:` struct tag. The resulting map is then typically saved using something like JSON or TOML. If a value has no default value, it checks whether its value is non-zero. If a field has a `save:"-"` tag, it wil not be included in the resulting map. If a field implements ShouldSaver and returns false, it will not be included in the resulting map.
func NonPointerType ¶
NonPointerType returns a non-pointer version of the given type.
func NonPointerValue ¶
NonPointerValue returns a non-pointer version of the given value.
func NumAllFields ¶
NumAllFields returns the number of elemental fields in the given struct type using WalkFields.
func OnePointerValue ¶
OnePointerValue returns a value that is exactly one pointer away from a non-pointer value.
func PointerValue ¶
PointerValue returns a pointer to the given value if it is not already a pointer.
func SetFromDefaultTag ¶
SetFromDefaultTag sets the given value from the given default tag.
func SetFromDefaultTags ¶
SetFromDefaultTags sets the values of fields in the given struct based on `default:` default value struct field tags.
func SetMapRobust ¶
SetMapRobust robustly sets a map value using reflect.Value representations of the map, key, and value elements, ensuring that the proper types are used for the key and value elements using sensible conversions.
func SetRobust ¶
SetRobust robustly sets the 'to' value from the 'from' value. The 'to' value must be a pointer. It copies slices and maps robustly, and it can set a struct, slice, or map from a JSON-formatted string value. It also handles many other cases, so it is unlikely to fail.
Note that maps are not reset prior to setting, whereas slices are set to be fully equivalent to the source slice.
func ShortTypeName ¶
ShortTypeName returns the short version of a package-qualified type name which just has the last element of the path. This is what is used in standard Go programming, and is is used for the key to lookup reflect.Type names -- i.e., this is what you should save in a JSON file. The potential naming conflict is worth the brevity, and typically a given file will only contain mutually compatible, non-conflicting types. This is cached in ShortNames because the path.Base computation is apparently a bit slow.
func SliceDeleteAt ¶
SliceDeleteAt deletes the element at the given index in the given slice.
func SliceElementType ¶
SliceElementType returns the type of the elements of the given slice (which can be a pointer to a slice or a direct slice); just reflect.Type.Elem of slice type, but using this function bypasses any pointer issues and makes it more explicit what is going on.
func SliceElementValue ¶
SliceElementValue returns a new reflect.Value of the SliceElementType.
func SliceNewAt ¶
SliceNewAt inserts a new blank element at the given index in the given slice. -1 means the end.
func SliceSort ¶
SliceSort sorts a slice of basic values (see StructSliceSort for sorting a slice-of-struct using a specific field), using float, int, string, and time.Time conversions.
func StringJSON ¶
StringJSON returns an indented JSON string representation of the given value for printing/debugging.
func StructSliceSort ¶
StructSliceSort sorts the given slice of structs according to the given field indexes and sort direction, using float, int, string, and time.Time conversions. It will panic if the field indexes are invalid.
func StructTags ¶
StructTags returns a map[string]string of the tag string from a reflect.StructTag value.
func ToBool ¶
ToBool robustly converts to a bool any basic elemental type (including pointers to such) using a big type switch organized for greatest efficiency. It tries the bools.Booler interface if not a bool type. It falls back on reflection when all else fails.
func ToFloat ¶
ToFloat robustly converts to a float64 any basic elemental type (including pointers to such) using a big type switch organized for greatest efficiency, only falling back on reflection when all else fails.
func ToFloat32 ¶
ToFloat32 robustly converts to a float32 any basic elemental type (including pointers to such) using a big type switch organized for greatest efficiency, only falling back on reflection when all else fails.
func ToInt ¶
ToInt robustly converts to an int64 any basic elemental type (including pointers to such) using a big type switch organized for greatest efficiency, only falling back on reflection when all else fails.
func ToString ¶
ToString robustly converts anything to a String using a big type switch organized for greatest efficiency. First checks for string or []byte and returns that immediately, then checks for the Stringer interface as the preferred conversion (e.g., for enums), and then falls back on strconv calls for numeric types. If everything else fails, it uses fmt.Sprintf("%v") which always works, so there is no need for an error return value. It returns "nil" for any nil pointers, and byte is converted as string(byte), not the decimal representation.
func ToStringPrec ¶
ToStringPrec robustly converts anything to a String using given precision for converting floating values; using a value like 6 truncates the nuisance random imprecision of actual floating point values due to the fact that they are represented with binary bits. Otherwise is identical to ToString for any other cases.
func Underlying ¶ added in v0.2.0
Underlying returns the actual underlying version of the given value, going through any pointers and interfaces.
func UnderlyingPointer ¶ added in v0.2.0
UnderlyingPointer returns a pointer to the actual underlying version of the given value, going through any pointers and interfaces.
func ValueIsDefault ¶ added in v0.2.0
ValueIsDefault returns whether the given value is equivalent to the given string representation used in a field default tag.
func ValueSliceSort ¶
ValueSliceSort sorts a slice of [reflect.Value]s using basic types where possible.
func WalkFields ¶ added in v0.2.0
func WalkFields(parent reflect.Value, should func(parent reflect.Value, field reflect.StructField, value reflect.Value) bool, walk func(parent reflect.Value, parentField *reflect.StructField, field reflect.StructField, value reflect.Value))
WalkFields calls the given walk function on all the exported primary fields of the given parent struct value, including those on anonymous embedded structs that this struct has. It effectively flattens all of the embedded fields of the struct.
It passes the current parent struct, current reflect.StructField, and current field value to the given should and walk functions.
The given should function is called on every struct field (including on embedded structs themselves) to determine whether that field and any fields it has embedded should be handled (a return value of true indicates to continue down and a value of false indicates to not).
Types ¶
type SetAnyer ¶
SetAnyer represents a type that can be set from any value. It is checked in SetRobust.
type SetColorer ¶ added in v0.2.1
SetColorer represents a type that can be set from a color value. It is checked in SetRobust.
type SetStringer ¶
SetStringer represents a type that can be set from a string value. It is checked in SetRobust.
type ShouldSaver ¶ added in v0.2.1
type ShouldSaver interface {
// ShouldSave returns whether this value should be included in the
// result of [NonDefaultFields].
ShouldSave() bool
}
ShouldSaver is an interface that types can implement to specify whether a value should be included in the result of NonDefaultFields.
Source Files