ident: member interface

For representing full identifiers of system and member.

Signed-off-by: Yonah <contrib@gensokyo.uk>

ident/ident.go

@@ -3,7 +3,9 @@
 package ident
 
 import (
+	"encoding"
 	"errors"
+	"fmt"
 	"strconv"
 )
 
@@ -21,3 +23,21 @@ func (e *UnexpectedSizeError) Error() string {
 	return "got " + strconv.Itoa(len(e.Data)) + " bytes for " +
 		"a " + strconv.Itoa(e.Want) + "-byte identifier"
 }
+
+// MS is a system or member identifier.
+type MS interface {
+	encoding.TextMarshaler
+	encoding.TextUnmarshaler
+	fmt.Stringer
+
+	// EncodedSize returns the number of bytes appended by Encode.
+	EncodedSize() int
+	// Encode appends the canonical string representation of MS to dst and
+	// returns the extended buffer.
+	Encode(dst []byte) []byte
+
+	// ident is a no-op function but serves to distinguish types that are
+	// identifiers from ordinary types with custom marshaler/unmarshaler
+	// behaviour: a type is an identifier part if it has an ident method.
+	ident()
+}