Interfaces for thesaurus datatype

segment.go

@@ -178,3 +178,37 @@
 	Aggregate(stats FieldStats)
 	Fetch() map[string]map[string]uint64
 }
+
+type ThesaurusSegment interface {
+	Segment
+	Thesaurus(field string) (Thesaurus, error)
+}
+
+type Thesaurus interface {
+	SynonymsList(term []byte, except *roaring.Bitmap, prealloc SynonymsList) (SynonymsList, error)
+
+	AutomatonIterator(a Automaton,
+		startKeyInclusive, endKeyExclusive []byte) ThesaurusIterator
+
+	Contains(key []byte) (bool, error)
+}
+
+type ThesaurusIterator interface {
+	Next() (*index.ThesaurusEntry, error)
+}
+
+type SynonymsList interface {
+	Iterator(prealloc SynonymsIterator) SynonymsIterator
+	Size() int
+}
+
+type SynonymsIterator interface {
+	Next() (Synonym, error)
+	Size() int
+}
+
+type Synonym interface {
+	Number() uint32
+	Term() string
+	Size() int
+}