code: func NewFieldTypeFrom(ref *FieldType) *FieldType {
  	ft := newFieldType()
  	ft.indexed = ref.indexed
  	ft.stored = ref.stored
  	ft._tokenized = ref._tokenized
  	ft.storeTermVectors = ref.storeTermVectors
  	ft.storeTermVectorOffsets = ref.storeTermVectorOffsets
  	ft.storeTermVectorPositions = ref.storeTermVectorPositions
  	ft.storeTermVectorPayloads = ref.storeTermVectorPayloads
  	ft._omitNorms = ref._omitNorms
  	ft._indexOptions = ref._indexOptions
  	ft._docValueType = ref._docValueType
  	ft.numericType = ref.numericType
  	// Do not copy frozen!
  	return ft
  }
docs: // Create a new mutable FieldType with all of the properties from <code>ref</code>