Support streaming iwslt2017 dataset (#4992)

Commit from https://github.com/huggingface/datasets/commit/5b7cc0b1ceae98b9791e9df102ee279fabedd469

iwslt2017.py

@@ -20,6 +20,12 @@ import os
 import datasets
 
 
+_HOMEPAGE = "https://sites.google.com/site/iwsltevaluation2017/TED-tasks"
+
+_DESCRIPTION = """\
+The IWSLT 2017 Multilingual Task addresses text translation, including zero-shot translation, with a single MT system across all directions including English, German, Dutch, Italian and Romanian. As unofficial task, conventional bilingual text translation is offered between English and Arabic, French, Japanese, Chinese, German and Korean.
+"""
+
 _CITATION = """\
 @inproceedings{cettolo-etal-2017-overview,
     title = "Overview of the {IWSLT} 2017 Evaluation Campaign",
@@ -41,11 +47,9 @@ _CITATION = """\
 }
 """
 
-_DESCRIPTION = """\
-The IWSLT 2017 Multilingual Task addresses text translation, including zero-shot translation, with a single MT system across all directions including English, German, Dutch, Italian and Romanian. As unofficial task, conventional bilingual text translation is offered between English and Arabic, French, Japanese, Chinese, German and Korean.
-"""
-
-MULTI_URL = "https://huggingface.co/datasets/iwslt2017/resolve/ebd7c60d9800c2a1be010a227e5f0a2363730f7a/data/2017-01-trnmted/texts/DeEnItNlRo/DeEnItNlRo/DeEnItNlRo-DeEnItNlRo.tgz"
+REPO_URL = "https://huggingface.co/datasets/iwslt2017/resolve/main/"
+MULTI_URL = REPO_URL + "data/2017-01-trnmted/texts/DeEnItNlRo/DeEnItNlRo/DeEnItNlRo-DeEnItNlRo.zip"
+BI_URL = REPO_URL + "data/2017-01-trnted/texts/{source}/{target}/{source}-{target}.zip"
 
 
 class IWSLT2017Config(datasets.BuilderConfig):
@@ -100,18 +104,11 @@ class IWSLT217(datasets.GeneratorBasedBuilder):
 
     def _info(self):
         return datasets.DatasetInfo(
-            # This is the description that will appear on the datasets page.
             description=_DESCRIPTION,
-            # datasets.features.FeatureConnectors
             features=datasets.Features(
                 {"translation": datasets.features.Translation(languages=self.config.pair.split("-"))}
             ),
-            # If there's a common (input, target) tuple from the features,
-            # specify them here. They'll be used if as_supervised=True in
-            # builder.as_dataset.
-            supervised_keys=None,
-            # Homepage of the dataset for documentation
-            homepage="https://sites.google.com/site/iwsltevaluation2017/TED-tasks",
+            homepage=_HOMEPAGE,
             citation=_CITATION,
         )
 
@@ -123,14 +120,13 @@ class IWSLT217(datasets.GeneratorBasedBuilder):
             data_dir = os.path.join(dl_dir, "DeEnItNlRo-DeEnItNlRo")
             years = [2010]
         else:
-            bi_url = f"https://huggingface.co/datasets/iwslt2017/resolve/ebd7c60d9800c2a1be010a227e5f0a2363730f7a/data/2017-01-trnted/texts/{source}/{target}/{source}-{target}.tgz"
+            bi_url = BI_URL.format(source=source, target=target)
             dl_dir = dl_manager.download_and_extract(bi_url)
             data_dir = os.path.join(dl_dir, f"{source}-{target}")
             years = [2010, 2011, 2012, 2013, 2014, 2015]
         return [
             datasets.SplitGenerator(
                 name=datasets.Split.TRAIN,
-                # These kwargs will be passed to _generate_examples
                 gen_kwargs={
                     "source_files": [
                         os.path.join(
@@ -144,12 +140,10 @@ class IWSLT217(datasets.GeneratorBasedBuilder):
                             f"train.tags.{self.config.pair}.{target}",
                         )
                     ],
-                    "split": "train",
                 },
             ),
             datasets.SplitGenerator(
                 name=datasets.Split.TEST,
-                # These kwargs will be passed to _generate_examples
                 gen_kwargs={
                     "source_files": [
                         os.path.join(
@@ -165,12 +159,10 @@ class IWSLT217(datasets.GeneratorBasedBuilder):
                         )
                         for year in years
                     ],
-                    "split": "test",
                 },
             ),
             datasets.SplitGenerator(
                 name=datasets.Split.VALIDATION,
-                # These kwargs will be passed to _generate_examples
                 gen_kwargs={
                     "source_files": [
                         os.path.join(
@@ -184,12 +176,11 @@ class IWSLT217(datasets.GeneratorBasedBuilder):
                             f"IWSLT17.TED.dev2010.{self.config.pair}.{target}.xml",
                         )
                     ],
-                    "split": "dev",
                 },
             ),
         ]
 
-    def _generate_examples(self, source_files, target_files, split):
+    def _generate_examples(self, source_files, target_files):
         """Yields examples."""
         id_ = 0
         source, target = self.config.pair.split("-")