Add iterator for strings

emoji.go

@@ -1,4 +1,4 @@
-package freetype
+package emoji
 
 import (
 	"fmt"
@@ -9,12 +9,12 @@ import (
 	"unicode/utf8"
 )
 
-// Emoji is a node of an EmojiTable
+// Emoji is a node of a Table
 type Emoji struct {
 	Codepoint []rune
 	IsEmoji   bool
 	Path      string
-	Sub       EmojiTable
+	Sub       Table
 }
 
 func (e Emoji) String() (str string) {
@@ -41,11 +41,11 @@ func (e Emoji) Length() int {
 	return total
 }
 
-// EmojiTable is a table of detected Unicode codepoints sequences for which an emoticon is available
-type EmojiTable map[rune]Emoji
+// Table is a table of detected Unicode codepoints sequences for which an emoticon is available
+type Table map[rune]Emoji
 
 // Find checks if a given strings begins with an emoji made by one or more sequential runes
-func (em EmojiTable) Find(str string) *Emoji {
+func (em Table) Find(str string) *Emoji {
 	for i, r := range str {
 		e, ok := em[r]
 		if !ok {
@@ -67,12 +67,12 @@ func (em EmojiTable) Find(str string) *Emoji {
 }
 
 // IsEmoji checks whether the given rune is an emoji
-func (em EmojiTable) IsEmoji(cp rune) bool {
+func (em Table) IsEmoji(cp rune) bool {
 	_, ok := em[cp]
 	return ok
 }
 
-func (em EmojiTable) tostring(indent string, nomarker bool) (str string) {
+func (em Table) tostring(indent string, nomarker bool) (str string) {
 	counter := len(em)
 	marker := "│ "
 	if nomarker {
@@ -96,7 +96,7 @@ func (em EmojiTable) tostring(indent string, nomarker bool) (str string) {
 	return
 }
 
-func (em EmojiTable) String() string {
+func (em Table) String() string {
 	return "Emoji table\n" + em.tostring("", true)
 }
 
@@ -105,8 +105,8 @@ func (em EmojiTable) String() string {
 //    emoji_uXXXX_XXXX.png
 // where XXXX are Unicode codepoints
 // See <https://github.com/googlei18n/noto-emoji/tree/master/png/128>
-func ScanEmojiDirectory(emojipath string) (tab EmojiTable, err error) {
-	tab = make(EmojiTable)
+func ScanEmojiDirectory(emojipath string) (tab Table, err error) {
+	tab = make(Table)
 	filepath.Walk(emojipath, func(path string, info os.FileInfo, err error) error {
 		// Ignore non-images
 		if !strings.HasSuffix(strings.ToLower(path), ".png") {
@@ -143,7 +143,7 @@ func ScanEmojiDirectory(emojipath string) (tab EmojiTable, err error) {
 			} else {
 				// Add sub-entry if not existant
 				if newemo.Sub == nil {
-					newemo.Sub = make(EmojiTable)
+					newemo.Sub = make(Table)
 				}
 			}
 			(*curtab)[cprune] = newemo

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
+
+}