use text.extract_iter where applicable

gallery_dl/extractor/kissmanga.py

@@ -37,14 +37,9 @@ class KissmangaMangaExtractor(KissmangaExtractor):
     def get_chapters(self):
         """Return a list of all chapter urls"""
         page = self.request(self.url).text
-        pos = 0
-        chapters = []
-        while True:
-            url, pos = text.extract(page, '<td>\n<a href="', '"', pos)
-            if not url:
-                chapters.reverse()
-                return chapters
-            chapters.append(url)
+        return reversed(list(
+            text.extract_iter(page, '<td>\n<a href="', '"')
+        ))
 
 
 class KissmangaChapterExtractor(KissmangaExtractor):

gallery_dl/extractor/mangahere.py

@@ -30,14 +30,10 @@ class MangaHereMangaExtractor(Extractor):
 
     def get_chapters(self):
         page = self.request(self.url).text
-        pos = page.index('<div class="detail_list">')
-        chapters = []
-        while True:
-            url, pos = text.extract(page, '<a class="color_0077" href="', '"', pos)
-            if not url:
-                chapters.reverse()
-                return chapters
-            chapters.append(url)
+        return reversed(list(
+            text.extract_iter(page, '<a class="color_0077" href="', '"',
+            page.index('<div class="detail_list">'))
+        ))
 
 
 class MangaHereChapterExtractor(AsynchronousExtractor):

gallery_dl/extractor/mangareader.py

@@ -33,10 +33,7 @@ class MangaReaderMangaExtractor(MangaReaderBase, Extractor):
         page = self.request(url).text
         needle = '<a href="' + self.url_title
         pos = page.index('<div id="readmangasum">')
-        while True:
-            chapter, pos = text.extract(page, needle, '"', pos)
-            if not chapter:
-                return
+        for chapter in text.extract_iter(page, needle, '"', pos):
             yield Message.Queue, url + chapter