Add iterator for strings

iterator.go

@@ -0,0 +1,43 @@
+package emoji
+
+// Fragment is either a rune or an emoji
+type Fragment struct {
+	Offset  int
+	IsEmoji bool
+	Emoji   Emoji
+	Rune    rune
+}
+
+// Iterate iterates through a string and returns its runes (for characters) and emojis
+func (em Table) Iterate(str string) <-chan Fragment {
+	c := make(chan Fragment)
+	go func() {
+		nextchar := 0
+		for index, r := range str {
+			// Check if we need to skip entries
+			if nextchar > index {
+				continue
+			}
+			// Check if rune is an emoji
+			if em.IsEmoji(r) {
+				icon := em.Find(str[index:])
+				if icon != nil {
+					nextchar = index + icon.Length() - 1
+					c <- Fragment{
+						IsEmoji: true,
+						Offset:  index,
+						Emoji:   *icon,
+					}
+					continue
+				}
+			}
+			c <- Fragment{
+				IsEmoji: false,
+				Offset:  index,
+				Rune:    r,
+			}
+		}
+	}()
+	return c
+
+}