Package identifier defines the contract between implementations of Encoding and Index by defining identifiers that uniquely identify standardized coded character sets (CCS) and character encoding schemes (CES), which we will together refer to as encodings, for which Encoding implementations provide converters to and from UTF-8.

Encoding is an implementation of the Encoding interface that adds the String and ID methods to an existing encoding.

FuncEncoding is an Encoding that combines two functions returning a new Transformer.

SimpleEncoding is an Encoding that combines two Transformers.

A RepertoireError indicates a rune is not in the repertoire of a destination encoding.