Interface List

reflect/protoreflect/value.go:180–226

List is a zero-indexed, ordered list. The element [Value] type is determined by [FieldDescriptor.Kind]. Providing a [Value] that is invalid or of an incorrect type panics.

// The element [Value] type is determined by [FieldDescriptor.Kind].
// Providing a [Value] that is invalid or of an incorrect type panics.
type List interface {
	// Len reports the number of entries in the List.
	// Get, Set, and Truncate panic with out of bound indexes.
	Len() int

	// Get retrieves the value at the given index.
	// It never returns an invalid value.
	Get(int) Value

	// Set stores a value for the given index.
	// When setting a composite type, it is unspecified whether the set
	// value aliases the source's memory in any way.
	//
	// Set is a mutating operation and unsafe for concurrent use.
	Set(int, Value)

	// Append appends the provided value to the end of the list.
	// When appending a composite type, it is unspecified whether the appended
	// value aliases the source's memory in any way.
	//
	// Append is a mutating operation and unsafe for concurrent use.
	Append(Value)

	// AppendMutable appends a new, empty, mutable message value to the end
	// of the list and returns it.
	// It panics if the list does not contain a message type.
	AppendMutable() Value

	// Truncate truncates the list to a smaller length.
	//
	// Truncate is a mutating operation and unsafe for concurrent use.
	Truncate(int)

	// NewElement returns a new value for a list element.
	// For enums, this returns the first enum value.
	// For other scalars, this returns the zero value.
	// For messages, this returns a new, empty, mutable value.
	NewElement() Value

	// IsValid reports whether the list is valid.
	//
	// An invalid list is an empty, read-only value.
	//
	// Validity is not part of the protobuf data model, and may not
	// be preserved in marshaling or other operations.
	IsValid() bool
}

// Map is an unordered, associative map.
// The entry [MapKey] type is determined by [FieldDescriptor.MapKey].Kind.