Add loading script (#2)

- Add original wmt_utils.py file (00a53ae8404e9afc5fb9abf2d9a70dd9f83c13d2)
- Refactor wmt_utils to add language_pair to SubDataset (e1feddcb2ff69f22e0ab180221b3b1e737c79c6c)
- Fix _parse_tsv (c33747773cc5ab9f5a64f735cf0fb40bf8cac2bf)
- Update wmt_utils with Wikititles v3 (0f9f475650a24b678d534e85b4f0916bebe24168)
- Add loading script (eb0b4a7dea25f6ec5906d2144f74d75e7271174c)

wikititles.py

@@ -0,0 +1,41 @@
+import datasets
+
+from .wmt_utils import Wmt, WmtConfig
+
+
+_URL = "http://www.statmt.org/wmt22/translation-task.html"
+# TODO: Update with citation of overview paper once it is published.
+_CITATION = """
+@ONLINE {wmt22translate,
+    author = {Wikimedia Foundation},
+    title  = {EMNLP 2022 Seventh Conference on Machine Translation (WMT22), Shared Task: General Machine Translation},
+    url    = {http://www.statmt.org/wmt22/translation-task.html}
+}
+"""
+
+
+_LANGUAGE_PAIRS = (
+    {(src, "en") for src in ["cs", "de", "ha", "ig", "is", "ja", "ps", "ru", "zh"]}
+    | {("ca", "es"), ("de", "fr"), ("bn", "hi")}
+    | {(src, "pt") for src in ["ca", "es"]}
+    | {(src, "ro") for src in ["ca", "es", "pt"]}
+    | {("xh", "zu")}
+)
+
+
+class Wikititles(Wmt):
+
+    BUILDER_CONFIGS = [
+        WmtConfig(
+            description="Wikititles v3 {0}-{1} translation dataset".format(*language_pair),
+            url=_URL,
+            citation=_CITATION,
+            language_pair=language_pair,
+            version=datasets.Version("3.0.0"),
+        )
+        for language_pair in _LANGUAGE_PAIRS
+    ]
+
+    @property
+    def _subsets(self):
+        return {datasets.Split.TRAIN: ["wikititles_v3"]}

wmt_utils.py

@@ -0,0 +1,1050 @@
+"""WMT: Translate dataset."""
+
+
+import codecs
+import functools
+import glob
+import gzip
+import itertools
+import os
+import re
+import xml.etree.cElementTree as ElementTree
+
+import datasets
+
+
+logger = datasets.logging.get_logger(__name__)
+
+
+_DESCRIPTION = """\
+Translation dataset based on the data from statmt.org.
+
+Versions exist for different years using a combination of data
+sources. The base `wmt` allows you to create a custom dataset by choosing
+your own data/language pair. This can be done as follows:
+
+```python
+from datasets import inspect_dataset, load_dataset_builder
+
+inspect_dataset("wmt19", "path/to/scripts")
+builder = load_dataset_builder(
+    "path/to/scripts/wmt_utils.py",
+    language_pair=("fr", "de"),
+    subsets={
+        datasets.Split.TRAIN: ["commoncrawl_frde"],
+        datasets.Split.VALIDATION: ["euelections_dev2019"],
+    },
+)
+
+# Standard version
+builder.download_and_prepare()
+ds = builder.as_dataset()
+
+# Streamable version
+ds = builder.as_streaming_dataset()
+```
+
+"""
+
+
+CWMT_SUBSET_NAMES = ["casia2015", "casict2011", "casict2015", "datum2015", "datum2017", "neu2017"]
+
+
+class SubDataset:
+    """Class to keep track of information on a sub-dataset of WMT."""
+
+    def __init__(self, name, url, path="", target=None, sources=None, language_pairs=None, manual_dl_files=None):
+        """Sub-dataset of WMT.
+
+        Args:
+          name: `string`, a unique dataset identifier.
+          target: `string`, the target language code.
+          sources: `set<string>`, the set of source language codes.
+          url: `string` or `(string, string)`, URL(s) or URL template(s) specifying
+            where to download the raw data from. If two strings are provided, the
+            first is used for the source language and the second for the target.
+            Template strings can either contain '{src}' placeholders that will be
+            filled in with the source language code, '{0}' and '{1}' placeholders
+            that will be filled in with the source and target language codes in
+            alphabetical order, or all 3.
+          path: `string` or `(string, string)`, path(s) or path template(s)
+            specifing the path to the raw data relative to the root of the
+            downloaded archive. If two strings are provided, the dataset is assumed
+            to be made up of parallel text files, the first being the source and the
+            second the target. If one string is provided, both languages are assumed
+            to be stored within the same file and the extension is used to determine
+            how to parse it. Template strings should be formatted the same as in
+            `url`.
+          manual_dl_files: `<list>(string)` (optional), the list of files that must
+            be manually downloaded to the data directory.
+        """
+        self._paths = (path,) if isinstance(path, str) else path
+        self._urls = (url,) if isinstance(url, str) else url
+        self._manual_dl_files = manual_dl_files if manual_dl_files else []
+        self.name = name
+        self.target = target
+        self.sources = set(sources) if sources else sources
+        self.language_pairs = language_pairs if language_pairs else {(src, target) for src in self.sources}
+
+    def _inject_language(self, src, tgt, strings):
+        """Injects languages into (potentially) template strings."""
+        if (src, tgt) not in self.language_pairs:
+            raise ValueError(f"Invalid source for '{self.name}': ({src}-{tgt})")
+
+        def _format_string(s):
+            if "{0}" in s and "{1}" in s and "{src}" in s:
+                return s.format(*sorted([src, tgt]), src=src)
+            elif "{0}" in s and "{1}" in s:
+                return s.format(*sorted([src, tgt]))
+            elif "{src}" in s:
+                return s.format(src=src, tgt=tgt)
+            else:
+                return s
+
+        return [_format_string(s) for s in strings]
+
+    def get_url(self, src, tgt):
+        return self._inject_language(src=src, tgt=tgt, strings=self._urls)
+
+    def get_manual_dl_files(self, src, tgt):
+        return self._inject_language(src=src, tgt=tgt, strings=self._manual_dl_files)
+
+    def get_path(self, src, tgt):
+        return self._inject_language(src=src, tgt=tgt, strings=self._paths)
+
+
+# Subsets used in the training sets for various years of WMT.
+_TRAIN_SUBSETS = [
+    # pylint:disable=line-too-long
+    SubDataset(
+        name="commoncrawl",
+        target="en",  # fr-de pair in commoncrawl_frde
+        sources={"cs", "de", "es", "fr", "ru"},
+        url="https://huggingface.co/datasets/wmt/wmt13/resolve/main-zip/training-parallel-commoncrawl.zip",
+        path=("commoncrawl.{src}-en.{src}", "commoncrawl.{src}-en.en"),
+    ),
+    SubDataset(
+        name="commoncrawl_frde",
+        target="de",
+        sources={"fr"},
+        url=(
+            "https://huggingface.co/datasets/wmt/wmt19/resolve/main/translation-task/fr-de/bitexts/commoncrawl.fr.gz",
+            "https://huggingface.co/datasets/wmt/wmt19/resolve/main/translation-task/fr-de/bitexts/commoncrawl.de.gz",
+        ),
+        path=("", ""),
+    ),
+    SubDataset(
+        name="czeng_10",
+        target="en",
+        sources={"cs"},
+        url="http://ufal.mff.cuni.cz/czeng/czeng10",
+        manual_dl_files=["data-plaintext-format.%d.tar" % i for i in range(10)],
+        # Each tar contains multiple files, which we process specially in
+        # _parse_czeng.
+        path=("data.plaintext-format/??train.gz",) * 10,
+    ),
+    SubDataset(
+        name="czeng_16pre",
+        target="en",
+        sources={"cs"},
+        url="http://ufal.mff.cuni.cz/czeng/czeng16pre",
+        manual_dl_files=["czeng16pre.deduped-ignoring-sections.txt.gz"],
+        path="",
+    ),
+    SubDataset(
+        name="czeng_16",
+        target="en",
+        sources={"cs"},
+        url="http://ufal.mff.cuni.cz/czeng",
+        manual_dl_files=["data-plaintext-format.%d.tar" % i for i in range(10)],
+        # Each tar contains multiple files, which we process specially in
+        # _parse_czeng.
+        path=("data.plaintext-format/??train.gz",) * 10,
+    ),
+    SubDataset(
+        # This dataset differs from the above in the filtering that is applied
+        # during parsing.
+        name="czeng_17",
+        target="en",
+        sources={"cs"},
+        url="http://ufal.mff.cuni.cz/czeng",
+        manual_dl_files=["data-plaintext-format.%d.tar" % i for i in range(10)],
+        # Each tar contains multiple files, which we process specially in
+        # _parse_czeng.
+        path=("data.plaintext-format/??train.gz",) * 10,
+    ),
+    SubDataset(
+        name="dcep_v1",
+        target="en",
+        sources={"lv"},
+        url="https://huggingface.co/datasets/wmt/wmt17/resolve/main-zip/translation-task/dcep.lv-en.v1.zip",
+        path=("dcep.en-lv/dcep.lv", "dcep.en-lv/dcep.en"),
+    ),
+    SubDataset(
+        name="europarl_v7",
+        target="en",
+        sources={"cs", "de", "es", "fr"},
+        url="https://huggingface.co/datasets/wmt/wmt13/resolve/main-zip/training-parallel-europarl-v7.zip",
+        path=("training/europarl-v7.{src}-en.{src}", "training/europarl-v7.{src}-en.en"),
+    ),
+    SubDataset(
+        name="europarl_v7_frde",
+        target="de",
+        sources={"fr"},
+        url=(
+            "https://huggingface.co/datasets/wmt/wmt19/resolve/main/translation-task/fr-de/bitexts/europarl-v7.fr.gz",
+            "https://huggingface.co/datasets/wmt/wmt19/resolve/main/translation-task/fr-de/bitexts/europarl-v7.de.gz",
+        ),
+        path=("", ""),
+    ),
+    SubDataset(
+        name="europarl_v8_18",
+        target="en",
+        sources={"et", "fi"},
+        url="https://huggingface.co/datasets/wmt/wmt18/resolve/main-zip/translation-task/training-parallel-ep-v8.zip",
+        path=("training/europarl-v8.{src}-en.{src}", "training/europarl-v8.{src}-en.en"),
+    ),
+    SubDataset(
+        name="europarl_v8_16",
+        target="en",
+        sources={"fi", "ro"},
+        url="https://huggingface.co/datasets/wmt/wmt16/resolve/main-zip/translation-task/training-parallel-ep-v8.zip",
+        path=("training-parallel-ep-v8/europarl-v8.{src}-en.{src}", "training-parallel-ep-v8/europarl-v8.{src}-en.en"),
+    ),
+    SubDataset(
+        name="europarl_v9",
+        target="en",
+        sources={"cs", "de", "fi", "lt"},
+        url="https://huggingface.co/datasets/wmt/europarl/resolve/main/v9/training/europarl-v9.{src}-en.tsv.gz",
+        path="",
+    ),
+    SubDataset(
+        name="gigafren",
+        target="en",
+        sources={"fr"},
+        url="https://huggingface.co/datasets/wmt/wmt10/resolve/main-zip/training-giga-fren.zip",
+        path=("giga-fren.release2.fixed.fr.gz", "giga-fren.release2.fixed.en.gz"),
+    ),
+    SubDataset(
+        name="hindencorp_01",
+        target="en",
+        sources={"hi"},
+        url="http://ufallab.ms.mff.cuni.cz/~bojar/hindencorp",
+        manual_dl_files=["hindencorp0.1.gz"],
+        path="",
+    ),
+    SubDataset(
+        name="leta_v1",
+        target="en",
+        sources={"lv"},
+        url="https://huggingface.co/datasets/wmt/wmt17/resolve/main-zip/translation-task/leta.v1.zip",
+        path=("LETA-lv-en/leta.lv", "LETA-lv-en/leta.en"),
+    ),
+    SubDataset(
+        name="multiun",
+        target="en",
+        sources={"es", "fr"},
+        url="https://huggingface.co/datasets/wmt/wmt13/resolve/main-zip/training-parallel-un.zip",
+        path=("un/undoc.2000.{src}-en.{src}", "un/undoc.2000.{src}-en.en"),
+    ),
+    SubDataset(
+        name="newscommentary_v9",
+        target="en",
+        sources={"cs", "de", "fr", "ru"},
+        url="https://huggingface.co/datasets/wmt/wmt14/resolve/main-zip/training-parallel-nc-v9.zip",
+        path=("training/news-commentary-v9.{src}-en.{src}", "training/news-commentary-v9.{src}-en.en"),
+    ),
+    SubDataset(
+        name="newscommentary_v10",
+        target="en",
+        sources={"cs", "de", "fr", "ru"},
+        url="https://huggingface.co/datasets/wmt/wmt15/resolve/main-zip/training-parallel-nc-v10.zip",
+        path=("news-commentary-v10.{src}-en.{src}", "news-commentary-v10.{src}-en.en"),
+    ),
+    SubDataset(
+        name="newscommentary_v11",
+        target="en",
+        sources={"cs", "de", "ru"},
+        url="https://huggingface.co/datasets/wmt/wmt16/resolve/main-zip/translation-task/training-parallel-nc-v11.zip",
+        path=(
+            "training-parallel-nc-v11/news-commentary-v11.{src}-en.{src}",
+            "training-parallel-nc-v11/news-commentary-v11.{src}-en.en",
+        ),
+    ),
+    SubDataset(
+        name="newscommentary_v12",
+        target="en",
+        sources={"cs", "de", "ru", "zh"},
+        url="https://huggingface.co/datasets/wmt/wmt17/resolve/main-zip/translation-task/training-parallel-nc-v12.zip",
+        path=("training/news-commentary-v12.{src}-en.{src}", "training/news-commentary-v12.{src}-en.en"),
+    ),
+    SubDataset(
+        name="newscommentary_v13",
+        target="en",
+        sources={"cs", "de", "ru", "zh"},
+        url="https://huggingface.co/datasets/wmt/wmt18/resolve/main-zip/translation-task/training-parallel-nc-v13.zip",
+        path=(
+            "training-parallel-nc-v13/news-commentary-v13.{src}-en.{src}",
+            "training-parallel-nc-v13/news-commentary-v13.{src}-en.en",
+        ),
+    ),
+    SubDataset(
+        name="newscommentary_v14",
+        target="en",  # fr-de pair in newscommentary_v14_frde
+        sources={"cs", "de", "kk", "ru", "zh"},
+        url="http://data.statmt.org/news-commentary/v14/training/news-commentary-v14.{0}-{1}.tsv.gz",
+        path="",
+    ),
+    SubDataset(
+        name="newscommentary_v14_frde",
+        target="de",
+        sources={"fr"},
+        url="http://data.statmt.org/news-commentary/v14/training/news-commentary-v14.de-fr.tsv.gz",
+        path="",
+    ),
+    SubDataset(
+        name="onlinebooks_v1",
+        target="en",
+        sources={"lv"},
+        url="https://huggingface.co/datasets/wmt/wmt17/resolve/main-zip/translation-task/books.lv-en.v1.zip",
+        path=("farewell/farewell.lv", "farewell/farewell.en"),
+    ),
+    SubDataset(
+        name="paracrawl_v1",
+        target="en",
+        sources={"cs", "de", "et", "fi", "ru"},
+        url="https://s3.amazonaws.com/web-language-models/paracrawl/release1/paracrawl-release1.en-{src}.zipporah0-dedup-clean.tgz",  # TODO(QL): use gzip for streaming
+        path=(
+            "paracrawl-release1.en-{src}.zipporah0-dedup-clean.{src}",
+            "paracrawl-release1.en-{src}.zipporah0-dedup-clean.en",
+        ),
+    ),
+    SubDataset(
+        name="paracrawl_v1_ru",
+        target="en",
+        sources={"ru"},
+        url="https://s3.amazonaws.com/web-language-models/paracrawl/release1/paracrawl-release1.en-ru.zipporah0-dedup-clean.tgz",  # TODO(QL): use gzip for streaming
+        path=(
+            "paracrawl-release1.en-ru.zipporah0-dedup-clean.ru",
+            "paracrawl-release1.en-ru.zipporah0-dedup-clean.en",
+        ),
+    ),
+    SubDataset(
+        name="paracrawl_v3",
+        target="en",  # fr-de pair in paracrawl_v3_frde
+        sources={"cs", "de", "fi", "lt"},
+        url="https://s3.amazonaws.com/web-language-models/paracrawl/release3/en-{src}.bicleaner07.tmx.gz",
+        path="",
+    ),
+    SubDataset(
+        name="paracrawl_v3_frde",
+        target="de",
+        sources={"fr"},
+        url=(
+            "https://huggingface.co/datasets/wmt/wmt19/resolve/main/translation-task/fr-de/bitexts/de-fr.bicleaner07.de.gz",
+            "https://huggingface.co/datasets/wmt/wmt19/resolve/main/translation-task/fr-de/bitexts/de-fr.bicleaner07.fr.gz",
+        ),
+        path=("", ""),
+    ),
+    SubDataset(
+        name="rapid_2016",
+        target="en",
+        sources={"de", "et", "fi"},
+        url="https://huggingface.co/datasets/wmt/wmt18/resolve/main-zip/translation-task/rapid2016.zip",
+        path=("rapid2016.{0}-{1}.{src}", "rapid2016.{0}-{1}.en"),
+    ),
+    SubDataset(
+        name="rapid_2016_ltfi",
+        target="en",
+        sources={"fi", "lt"},
+        url="https://tilde-model.s3-eu-west-1.amazonaws.com/rapid2016.en-{src}.tmx.zip",
+        path="rapid2016.en-{src}.tmx",
+    ),
+    SubDataset(
+        name="rapid_2019",
+        target="en",
+        sources={"de"},
+        url="https://s3-eu-west-1.amazonaws.com/tilde-model/rapid2019.de-en.zip",
+        path=("rapid2019.de-en.de", "rapid2019.de-en.en"),
+    ),
+    SubDataset(
+        name="setimes_2",
+        target="en",
+        sources={"ro", "tr"},
+        url="https://opus.nlpl.eu/download.php?f=SETIMES/v2/tmx/en-{src}.tmx.gz",
+        path="",
+    ),
+    SubDataset(
+        name="uncorpus_v1",
+        target="en",
+        sources={"ru", "zh"},
+        url="https://huggingface.co/datasets/wmt/uncorpus/resolve/main-zip/UNv1.0.en-{src}.zip",
+        path=("en-{src}/UNv1.0.en-{src}.{src}", "en-{src}/UNv1.0.en-{src}.en"),
+    ),
+    SubDataset(
+        name="wikiheadlines_fi",
+        target="en",
+        sources={"fi"},
+        url="https://huggingface.co/datasets/wmt/wmt15/resolve/main-zip/wiki-titles.zip",
+        path="wiki/fi-en/titles.fi-en",
+    ),
+    SubDataset(
+        name="wikiheadlines_hi",
+        target="en",
+        sources={"hi"},
+        url="https://huggingface.co/datasets/wmt/wmt14/resolve/main-zip/wiki-titles.zip",
+        path="wiki/hi-en/wiki-titles.hi-en",
+    ),
+    SubDataset(
+        # Verified that wmt14 and wmt15 files are identical.
+        name="wikiheadlines_ru",
+        target="en",
+        sources={"ru"},
+        url="https://huggingface.co/datasets/wmt/wmt15/resolve/main-zip/wiki-titles.zip",
+        path="wiki/ru-en/wiki.ru-en",
+    ),
+    SubDataset(
+        name="wikititles_v1",
+        target="en",
+        sources={"cs", "de", "fi", "gu", "kk", "lt", "ru", "zh"},
+        url="https://huggingface.co/datasets/wmt/wikititles/resolve/main/v1/wikititles-v1.{src}-en.tsv.gz",
+        path="",
+    ),
+    SubDataset(
+        name="wikititles_v3",
+        language_pairs={(src, "en") for src in ["cs", "de", "ha", "ig", "is", "ja", "ps", "ru", "zh"]}
+        | {("ca", "es"), ("de", "fr"), ("bn", "hi")}
+        | {(src, "pt") for src in ["ca", "es"]}
+        | {(src, "ro") for src in ["ca", "es", "pt"]}
+        | {("xh", "zu")},
+        url="https://huggingface.co/datasets/wmt/wikititles/resolve/main/data/v3/wikititles-v3.{src}-{tgt}.tsv.gz",
+    ),
+    SubDataset(
+        name="yakut",
+        target="ru",
+        sources={"sah"},
+        url="https://huggingface.co/datasets/wmt/yakut/resolve/main/data/yakut.zip",
+        path="yakut/sah-ru.parallel.uniq.tsv",
+    ),
+    SubDataset(
+        name="yandexcorpus",
+        target="en",
+        sources={"ru"},
+        url="https://translate.yandex.ru/corpus?lang=en",
+        manual_dl_files=["1mcorpus.zip"],
+        path=("corpus.en_ru.1m.ru", "corpus.en_ru.1m.en"),
+    ),
+    # pylint:enable=line-too-long
+] + [
+    SubDataset(  # pylint:disable=g-complex-comprehension
+        name=ss,
+        target="en",
+        sources={"zh"},
+        url="https://huggingface.co/datasets/wmt/wmt18/resolve/main/cwmt-wmt/%s.zip" % ss,
+        path=("%s/*_c[hn].txt" % ss, "%s/*_en.txt" % ss),
+    )
+    for ss in CWMT_SUBSET_NAMES
+]
+
+_DEV_SUBSETS = [
+    SubDataset(
+        name="euelections_dev2019",
+        target="de",
+        sources={"fr"},
+        url="https://huggingface.co/datasets/wmt/wmt19/resolve/main-zip/translation-task/dev.zip",
+        path=("dev/euelections_dev2019.fr-de.src.fr", "dev/euelections_dev2019.fr-de.tgt.de"),
+    ),
+    SubDataset(
+        name="newsdev2014",
+        target="en",
+        sources={"hi"},
+        url="https://huggingface.co/datasets/wmt/wmt19/resolve/main-zip/translation-task/dev.zip",
+        path=("dev/newsdev2014.hi", "dev/newsdev2014.en"),
+    ),
+    SubDataset(
+        name="newsdev2015",
+        target="en",
+        sources={"fi"},
+        url="https://huggingface.co/datasets/wmt/wmt19/resolve/main-zip/translation-task/dev.zip",
+        path=("dev/newsdev2015-fien-src.{src}.sgm", "dev/newsdev2015-fien-ref.en.sgm"),
+    ),
+    SubDataset(
+        name="newsdiscussdev2015",
+        target="en",
+        sources={"ro", "tr"},
+        url="https://huggingface.co/datasets/wmt/wmt19/resolve/main-zip/translation-task/dev.zip",
+        path=("dev/newsdiscussdev2015-{src}en-src.{src}.sgm", "dev/newsdiscussdev2015-{src}en-ref.en.sgm"),
+    ),
+    SubDataset(
+        name="newsdev2016",
+        target="en",
+        sources={"ro", "tr"},
+        url="https://huggingface.co/datasets/wmt/wmt19/resolve/main-zip/translation-task/dev.zip",
+        path=("dev/newsdev2016-{src}en-src.{src}.sgm", "dev/newsdev2016-{src}en-ref.en.sgm"),
+    ),
+    SubDataset(
+        name="newsdev2017",
+        target="en",
+        sources={"lv", "zh"},
+        url="https://huggingface.co/datasets/wmt/wmt19/resolve/main-zip/translation-task/dev.zip",
+        path=("dev/newsdev2017-{src}en-src.{src}.sgm", "dev/newsdev2017-{src}en-ref.en.sgm"),
+    ),
+    SubDataset(
+        name="newsdev2018",
+        target="en",
+        sources={"et"},
+        url="https://huggingface.co/datasets/wmt/wmt19/resolve/main-zip/translation-task/dev.zip",
+        path=("dev/newsdev2018-{src}en-src.{src}.sgm", "dev/newsdev2018-{src}en-ref.en.sgm"),
+    ),
+    SubDataset(
+        name="newsdev2019",
+        target="en",
+        sources={"gu", "kk", "lt"},
+        url="https://huggingface.co/datasets/wmt/wmt19/resolve/main-zip/translation-task/dev.zip",
+        path=("dev/newsdev2019-{src}en-src.{src}.sgm", "dev/newsdev2019-{src}en-ref.en.sgm"),
+    ),
+    SubDataset(
+        name="newsdiscussdev2015",
+        target="en",
+        sources={"fr"},
+        url="https://huggingface.co/datasets/wmt/wmt19/resolve/main-zip/translation-task/dev.zip",
+        path=("dev/newsdiscussdev2015-{src}en-src.{src}.sgm", "dev/newsdiscussdev2015-{src}en-ref.en.sgm"),
+    ),
+    SubDataset(
+        name="newsdiscusstest2015",
+        target="en",
+        sources={"fr"},
+        url="https://huggingface.co/datasets/wmt/wmt19/resolve/main-zip/translation-task/dev.zip",
+        path=("dev/newsdiscusstest2015-{src}en-src.{src}.sgm", "dev/newsdiscusstest2015-{src}en-ref.en.sgm"),
+    ),
+    SubDataset(
+        name="newssyscomb2009",
+        target="en",
+        sources={"cs", "de", "es", "fr"},
+        url="https://huggingface.co/datasets/wmt/wmt19/resolve/main-zip/translation-task/dev.zip",
+        path=("dev/newssyscomb2009.{src}", "dev/newssyscomb2009.en"),
+    ),
+    SubDataset(
+        name="newstest2008",
+        target="en",
+        sources={"cs", "de", "es", "fr", "hu"},
+        url="https://huggingface.co/datasets/wmt/wmt19/resolve/main-zip/translation-task/dev.zip",
+        path=("dev/news-test2008.{src}", "dev/news-test2008.en"),
+    ),
+    SubDataset(
+        name="newstest2009",
+        target="en",
+        sources={"cs", "de", "es", "fr"},
+        url="https://huggingface.co/datasets/wmt/wmt19/resolve/main-zip/translation-task/dev.zip",
+        path=("dev/newstest2009.{src}", "dev/newstest2009.en"),
+    ),
+    SubDataset(
+        name="newstest2010",
+        target="en",
+        sources={"cs", "de", "es", "fr"},
+        url="https://huggingface.co/datasets/wmt/wmt19/resolve/main-zip/translation-task/dev.zip",
+        path=("dev/newstest2010.{src}", "dev/newstest2010.en"),
+    ),
+    SubDataset(
+        name="newstest2011",
+        target="en",
+        sources={"cs", "de", "es", "fr"},
+        url="https://huggingface.co/datasets/wmt/wmt19/resolve/main-zip/translation-task/dev.zip",
+        path=("dev/newstest2011.{src}", "dev/newstest2011.en"),
+    ),
+    SubDataset(
+        name="newstest2012",
+        target="en",
+        sources={"cs", "de", "es", "fr", "ru"},
+        url="https://huggingface.co/datasets/wmt/wmt19/resolve/main-zip/translation-task/dev.zip",
+        path=("dev/newstest2012.{src}", "dev/newstest2012.en"),
+    ),
+    SubDataset(
+        name="newstest2013",
+        target="en",
+        sources={"cs", "de", "es", "fr", "ru"},
+        url="https://huggingface.co/datasets/wmt/wmt19/resolve/main-zip/translation-task/dev.zip",
+        path=("dev/newstest2013.{src}", "dev/newstest2013.en"),
+    ),
+    SubDataset(
+        name="newstest2014",
+        target="en",
+        sources={"cs", "de", "es", "fr", "hi", "ru"},
+        url="https://huggingface.co/datasets/wmt/wmt19/resolve/main-zip/translation-task/dev.zip",
+        path=("dev/newstest2014-{src}en-src.{src}.sgm", "dev/newstest2014-{src}en-ref.en.sgm"),
+    ),
+    SubDataset(
+        name="newstest2015",
+        target="en",
+        sources={"cs", "de", "fi", "ru"},
+        url="https://huggingface.co/datasets/wmt/wmt19/resolve/main-zip/translation-task/dev.zip",
+        path=("dev/newstest2015-{src}en-src.{src}.sgm", "dev/newstest2015-{src}en-ref.en.sgm"),
+    ),
+    SubDataset(
+        name="newsdiscusstest2015",
+        target="en",
+        sources={"fr"},
+        url="https://huggingface.co/datasets/wmt/wmt19/resolve/main-zip/translation-task/dev.zip",
+        path=("dev/newsdiscusstest2015-{src}en-src.{src}.sgm", "dev/newsdiscusstest2015-{src}en-ref.en.sgm"),
+    ),
+    SubDataset(
+        name="newstest2016",
+        target="en",
+        sources={"cs", "de", "fi", "ro", "ru", "tr"},
+        url="https://huggingface.co/datasets/wmt/wmt19/resolve/main-zip/translation-task/dev.zip",
+        path=("dev/newstest2016-{src}en-src.{src}.sgm", "dev/newstest2016-{src}en-ref.en.sgm"),
+    ),
+    SubDataset(
+        name="newstestB2016",
+        target="en",
+        sources={"fi"},
+        url="https://huggingface.co/datasets/wmt/wmt19/resolve/main-zip/translation-task/dev.zip",
+        path=("dev/newstestB2016-enfi-ref.{src}.sgm", "dev/newstestB2016-enfi-src.en.sgm"),
+    ),
+    SubDataset(
+        name="newstest2017",
+        target="en",
+        sources={"cs", "de", "fi", "lv", "ru", "tr", "zh"},
+        url="https://huggingface.co/datasets/wmt/wmt19/resolve/main-zip/translation-task/dev.zip",
+        path=("dev/newstest2017-{src}en-src.{src}.sgm", "dev/newstest2017-{src}en-ref.en.sgm"),
+    ),
+    SubDataset(
+        name="newstestB2017",
+        target="en",
+        sources={"fi"},
+        url="https://huggingface.co/datasets/wmt/wmt19/resolve/main-zip/translation-task/dev.zip",
+        path=("dev/newstestB2017-fien-src.fi.sgm", "dev/newstestB2017-fien-ref.en.sgm"),
+    ),
+    SubDataset(
+        name="newstest2018",
+        target="en",
+        sources={"cs", "de", "et", "fi", "ru", "tr", "zh"},
+        url="https://huggingface.co/datasets/wmt/wmt19/resolve/main-zip/translation-task/dev.zip",
+        path=("dev/newstest2018-{src}en-src.{src}.sgm", "dev/newstest2018-{src}en-ref.en.sgm"),
+    ),
+]
+
+DATASET_MAP = {dataset.name: dataset for dataset in _TRAIN_SUBSETS + _DEV_SUBSETS}
+
+_CZENG17_FILTER = SubDataset(
+    name="czeng17_filter",
+    target="en",
+    sources={"cs"},
+    url="http://ufal.mff.cuni.cz/czeng/download.php?f=convert_czeng16_to_17.pl.zip",
+    path="convert_czeng16_to_17.pl",
+)
+
+
+class WmtConfig(datasets.BuilderConfig):
+    """BuilderConfig for WMT."""
+
+    def __init__(self, url=None, citation=None, description=None, language_pair=(None, None), subsets=None, **kwargs):
+        """BuilderConfig for WMT.
+
+        Args:
+          url: The reference URL for the dataset.
+          citation: The paper citation for the dataset.
+          description: The description of the dataset.
+          language_pair: pair of languages that will be used for translation. Should
+                     contain 2 letter coded strings. For example: ("en", "de").
+            configuration for the `datasets.features.text.TextEncoder` used for the
+            `datasets.features.text.Translation` features.
+          subsets: Dict[split, list[str]]. List of the subset to use for each of the
+            split. Note that WMT subclasses overwrite this parameter.
+          **kwargs: keyword arguments forwarded to super.
+        """
+        name = "%s-%s" % (language_pair[0], language_pair[1])
+        if "name" in kwargs:  # Add name suffix for custom configs
+            name += "." + kwargs.pop("name")
+
+        super(WmtConfig, self).__init__(name=name, description=description, **kwargs)
+
+        self.url = url or "http://www.statmt.org"
+        self.citation = citation
+        self.language_pair = language_pair
+        self.subsets = subsets
+
+        # TODO(PVP): remove when manual dir works
+        # +++++++++++++++++++++
+        if language_pair[1] in ["cs", "hi", "ru"]:
+            assert NotImplementedError(f"The dataset for {language_pair[1]}-en is currently not fully supported.")
+        # +++++++++++++++++++++
+
+
+class Wmt(datasets.GeneratorBasedBuilder):
+    """WMT translation dataset."""
+
+    BUILDER_CONFIG_CLASS = WmtConfig
+
+    def __init__(self, *args, **kwargs):
+        super(Wmt, self).__init__(*args, **kwargs)
+
+    @property
+    def _subsets(self):
+        """Subsets that make up each split of the dataset."""
+        raise NotImplementedError("This is a abstract method")
+
+    @property
+    def subsets(self):
+        """Subsets that make up each split of the dataset for the language pair."""
+        language_pair = self.config.language_pair
+        filtered_subsets = {}
+        subsets = self._subsets if self.config.subsets is None else self.config.subsets
+        for split, ss_names in subsets.items():
+            filtered_subsets[split] = []
+            for ss_name in ss_names:
+                dataset = DATASET_MAP[ss_name]
+                if language_pair not in dataset.language_pairs:
+                    logger.info("Skipping sub-dataset that does not include language pair: %s", ss_name)
+                else:
+                    filtered_subsets[split].append(ss_name)
+        logger.info("Using sub-datasets: %s", filtered_subsets)
+        return filtered_subsets
+
+    def _info(self):
+        src, target = self.config.language_pair
+        return datasets.DatasetInfo(
+            description=_DESCRIPTION,
+            features=datasets.Features(
+                {"translation": datasets.features.Translation(languages=self.config.language_pair)}
+            ),
+            supervised_keys=(src, target),
+            homepage=self.config.url,
+            citation=self.config.citation,
+        )
+
+    def _vocab_text_gen(self, split_subsets, extraction_map, language):
+        for _, ex in self._generate_examples(split_subsets, extraction_map, with_translation=False):
+            yield ex[language]
+
+    def _split_generators(self, dl_manager):
+        source, target = self.config.language_pair
+        manual_paths_dict = {}
+        urls_to_download = {}
+        for ss_name in itertools.chain.from_iterable(self.subsets.values()):
+            if ss_name == "czeng_17":
+                # CzEng1.7 is CzEng1.6 with some blocks filtered out. We must download
+                # the filtering script so we can parse out which blocks need to be
+                # removed.
+                urls_to_download[_CZENG17_FILTER.name] = _CZENG17_FILTER.get_url(source, target)
+
+            # get dataset
+            dataset = DATASET_MAP[ss_name]
+            if dataset.get_manual_dl_files(source, target):
+                # TODO(PVP): following two lines skip configs that are incomplete for now
+                # +++++++++++++++++++++
+                logger.info("Skipping {dataset.name} for now. Incomplete dataset for {self.config.name}")
+                continue
+                # +++++++++++++++++++++
+
+                manual_dl_files = dataset.get_manual_dl_files(source, target)
+                manual_paths = [
+                    os.path.join(os.path.abspath(os.path.expanduser(dl_manager.manual_dir)), fname)
+                    for fname in manual_dl_files
+                ]
+                assert all(
+                    os.path.exists(path) for path in manual_paths
+                ), f"For {dataset.name}, you must manually download the following file(s) from {dataset.get_url(source, target)} and place them in {dl_manager.manual_dir}: {', '.join(manual_dl_files)}"
+
+                # set manual path for correct subset
+                manual_paths_dict[ss_name] = manual_paths
+            else:
+                urls_to_download[ss_name] = dataset.get_url(source, target)
+
+        # Download and extract files from URLs.
+        downloaded_files = dl_manager.download_and_extract(urls_to_download)
+        # Extract manually downloaded files.
+        manual_files = dl_manager.extract(manual_paths_dict)
+        extraction_map = dict(downloaded_files, **manual_files)
+
+        for language in self.config.language_pair:
+            self._vocab_text_gen(self.subsets[datasets.Split.TRAIN], extraction_map, language)
+
+        return [
+            datasets.SplitGenerator(  # pylint:disable=g-complex-comprehension
+                name=split, gen_kwargs={"split_subsets": split_subsets, "extraction_map": extraction_map}
+            )
+            for split, split_subsets in self.subsets.items()
+        ]
+
+    def _generate_examples(self, split_subsets, extraction_map, with_translation=True):
+        """Returns the examples in the raw (text) form."""
+        source, target = self.config.language_pair
+
+        def _get_local_paths(dataset, extract_dirs):
+            rel_paths = dataset.get_path(source, target)
+            if len(extract_dirs) == 1:
+                extract_dirs = extract_dirs * len(rel_paths)
+            return [
+                os.path.join(ex_dir, rel_path) if rel_path else ex_dir
+                for ex_dir, rel_path in zip(extract_dirs, rel_paths)
+            ]
+
+        def _get_filenames(dataset):
+            rel_paths = dataset.get_path(source, target)
+            urls = dataset.get_url(source, target)
+            if len(urls) == 1:
+                urls = urls * len(rel_paths)
+            return [rel_path if rel_path else os.path.basename(url) for url, rel_path in zip(urls, rel_paths)]
+
+        for ss_name in split_subsets:
+            # TODO(PVP) remove following five lines when manual data works
+            # +++++++++++++++++++++
+            dataset = DATASET_MAP[ss_name]
+            source, _ = self.config.language_pair
+            if dataset.get_manual_dl_files(source, target):
+                logger.info(f"Skipping {dataset.name} for now. Incomplete dataset for {self.config.name}")
+                continue
+            # +++++++++++++++++++++
+
+            logger.info("Generating examples from: %s", ss_name)
+            dataset = DATASET_MAP[ss_name]
+            extract_dirs = extraction_map[ss_name]
+            files = _get_local_paths(dataset, extract_dirs)
+            filenames = _get_filenames(dataset)
+
+            sub_generator_args = tuple(files)
+
+            if ss_name.startswith("czeng"):
+                if ss_name.endswith("16pre"):
+                    sub_generator = functools.partial(_parse_tsv, language_pair=("en", "cs"))
+                    sub_generator_args += tuple(filenames)
+                elif ss_name.endswith("17"):
+                    filter_path = _get_local_paths(_CZENG17_FILTER, extraction_map[_CZENG17_FILTER.name])[0]
+                    sub_generator = functools.partial(_parse_czeng, filter_path=filter_path)
+                else:
+                    sub_generator = _parse_czeng
+            elif ss_name == "hindencorp_01":
+                sub_generator = _parse_hindencorp
+            elif ss_name == "yakut":
+                sub_generator, sub_generator_args = YakutParser.create_generator(
+                    sub_generator_args=sub_generator_args, config=self.config
+                )
+            elif ss_name == "wikititles_v3":
+                sub_generator, sub_generator_args = WikititlesV3Parser.create_generator(
+                    sub_generator_args=sub_generator_args, config=self.config
+                )
+            elif len(files) == 2:
+                if ss_name.endswith("_frde"):
+                    sub_generator = _parse_frde_bitext
+                else:
+                    sub_generator = _parse_parallel_sentences
+                    sub_generator_args += tuple(filenames)
+            elif len(files) == 1:
+                fname = filenames[0]
+                # Note: Due to formatting used by `download_manager`, the file
+                # extension may not be at the end of the file path.
+                if ".tsv" in fname:
+                    sub_generator = _parse_tsv
+                    sub_generator_args += tuple(filenames)
+                elif (
+                    ss_name.startswith("newscommentary_v14")
+                    or ss_name.startswith("europarl_v9")
+                    or ss_name.startswith("wikititles_v1")
+                ):
+                    sub_generator = functools.partial(_parse_tsv, language_pair=self.config.language_pair)
+                    sub_generator_args += tuple(filenames)
+                elif "tmx" in fname or ss_name.startswith("paracrawl_v3"):
+                    sub_generator = _parse_tmx
+                elif ss_name.startswith("wikiheadlines"):
+                    sub_generator = _parse_wikiheadlines
+                else:
+                    raise ValueError("Unsupported file format: %s" % fname)
+            else:
+                raise ValueError("Invalid number of files: %d" % len(files))
+
+            for sub_key, ex in sub_generator(*sub_generator_args):
+                if not all(ex.values()):
+                    continue
+                # TODO(adarob): Add subset feature.
+                # ex["subset"] = subset
+                key = f"{ss_name}/{sub_key}"
+                if with_translation is True:
+                    ex = {"translation": ex}
+                yield key, ex
+
+
+def _parse_parallel_sentences(f1, f2, filename1, filename2):
+    """Returns examples from parallel SGML or text files, which may be gzipped."""
+
+    def _parse_text(path, original_filename):
+        """Returns the sentences from a single text file, which may be gzipped."""
+        split_path = original_filename.split(".")
+
+        if split_path[-1] == "gz":
+            lang = split_path[-2]
+
+            def gen():
+                with open(path, "rb") as f, gzip.GzipFile(fileobj=f) as g:
+                    for line in g:
+                        yield line.decode("utf-8").rstrip()
+
+            return gen(), lang
+
+        if split_path[-1] == "txt":
+            # CWMT
+            lang = split_path[-2].split("_")[-1]
+            lang = "zh" if lang in ("ch", "cn", "c[hn]") else lang
+        else:
+            lang = split_path[-1]
+
+        def gen():
+            with open(path, "rb") as f:
+                for line in f:
+                    yield line.decode("utf-8").rstrip()
+
+        return gen(), lang
+
+    def _parse_sgm(path, original_filename):
+        """Returns sentences from a single SGML file."""
+        lang = original_filename.split(".")[-2]
+        # Note: We can't use the XML parser since some of the files are badly
+        # formatted.
+        seg_re = re.compile(r"<seg id=\"\d+\">(.*)</seg>")
+
+        def gen():
+            with open(path, encoding="utf-8") as f:
+                for line in f:
+                    seg_match = re.match(seg_re, line)
+                    if seg_match:
+                        assert len(seg_match.groups()) == 1
+                        yield seg_match.groups()[0]
+
+        return gen(), lang
+
+    parse_file = _parse_sgm if os.path.basename(f1).endswith(".sgm") else _parse_text
+
+    # Some datasets (e.g., CWMT) contain multiple parallel files specified with
+    # a wildcard. We sort both sets to align them and parse them one by one.
+    f1_files = sorted(glob.glob(f1))
+    f2_files = sorted(glob.glob(f2))
+
+    assert f1_files and f2_files, "No matching files found: %s, %s." % (f1, f2)
+    assert len(f1_files) == len(f2_files), "Number of files do not match: %d vs %d for %s vs %s." % (
+        len(f1_files),
+        len(f2_files),
+        f1,
+        f2,
+    )
+
+    for f_id, (f1_i, f2_i) in enumerate(zip(sorted(f1_files), sorted(f2_files))):
+        l1_sentences, l1 = parse_file(f1_i, filename1)
+        l2_sentences, l2 = parse_file(f2_i, filename2)
+
+        for line_id, (s1, s2) in enumerate(zip(l1_sentences, l2_sentences)):
+            key = f"{f_id}/{line_id}"
+            yield key, {l1: s1, l2: s2}
+
+
+def _parse_frde_bitext(fr_path, de_path):
+    with open(fr_path, encoding="utf-8") as fr_f:
+        with open(de_path, encoding="utf-8") as de_f:
+            for line_id, (s1, s2) in enumerate(zip(fr_f, de_f)):
+                yield line_id, {"fr": s1.rstrip(), "de": s2.rstrip()}
+
+
+def _parse_tmx(path):
+    """Generates examples from TMX file."""
+
+    def _get_tuv_lang(tuv):
+        for k, v in tuv.items():
+            if k.endswith("}lang"):
+                return v
+        raise AssertionError("Language not found in `tuv` attributes.")
+
+    def _get_tuv_seg(tuv):
+        segs = tuv.findall("seg")
+        assert len(segs) == 1, "Invalid number of segments: %d" % len(segs)
+        return segs[0].text
+
+    with open(path, "rb") as f:
+        # Workaround due to: https://github.com/tensorflow/tensorflow/issues/33563
+        utf_f = codecs.getreader("utf-8")(f)
+        for line_id, (_, elem) in enumerate(ElementTree.iterparse(utf_f)):
+            if elem.tag == "tu":
+                yield line_id, {_get_tuv_lang(tuv): _get_tuv_seg(tuv) for tuv in elem.iterfind("tuv")}
+                elem.clear()
+
+
+def _parse_tsv(path, filename=None, language_pair=None, skiprows=None):
+    """Generates examples from TSV file."""
+    if language_pair is None:
+        lang_match = re.match(r".*\.([a-z][a-z])-([a-z][a-z])\.tsv", filename)
+        assert lang_match is not None, "Invalid TSV filename: %s" % filename
+        l1, l2 = lang_match.groups()
+    else:
+        l1, l2 = language_pair
+    with open(path, encoding="utf-8") as f:
+        for key, line in enumerate(f):
+            if skiprows and key < skiprows:
+                continue
+            cols = line.split("\t")
+            if len(cols) != 2:
+                logger.warning("Skipping line %d in TSV (%s) with %d != 2 columns.", key, path, len(cols))
+                continue
+            s1, s2 = cols
+            yield key, {l1: s1.strip(), l2: s2.strip()}
+
+
+def _parse_wikiheadlines(path):
+    """Generates examples from Wikiheadlines dataset file."""
+    lang_match = re.match(r".*\.([a-z][a-z])-([a-z][a-z])$", path)
+    assert lang_match is not None, "Invalid Wikiheadlines filename: %s" % path
+    l1, l2 = lang_match.groups()
+    with open(path, encoding="utf-8") as f:
+        for line_id, line in enumerate(f):
+            s1, s2 = line.split("|||")
+            yield line_id, {l1: s1.strip(), l2: s2.strip()}
+
+
+def _parse_czeng(*paths, **kwargs):
+    """Generates examples from CzEng v1.6, with optional filtering for v1.7."""
+    filter_path = kwargs.get("filter_path", None)
+    if filter_path:
+        re_block = re.compile(r"^[^-]+-b(\d+)-\d\d[tde]")
+        with open(filter_path, encoding="utf-8") as f:
+            bad_blocks = {blk for blk in re.search(r"qw{([\s\d]*)}", f.read()).groups()[0].split()}
+        logger.info("Loaded %d bad blocks to filter from CzEng v1.6 to make v1.7.", len(bad_blocks))
+
+    for path in paths:
+        for gz_path in sorted(glob.glob(path)):
+            with open(gz_path, "rb") as g, gzip.GzipFile(fileobj=g) as f:
+                filename = os.path.basename(gz_path)
+                for line_id, line in enumerate(f):
+                    line = line.decode("utf-8")  # required for py3
+                    if not line.strip():
+                        continue
+                    id_, unused_score, cs, en = line.split("\t")
+                    if filter_path:
+                        block_match = re.match(re_block, id_)
+                        if block_match and block_match.groups()[0] in bad_blocks:
+                            continue
+                    sub_key = f"{filename}/{line_id}"
+                    yield sub_key, {
+                        "cs": cs.strip(),
+                        "en": en.strip(),
+                    }
+
+
+def _parse_hindencorp(path):
+    with open(path, encoding="utf-8") as f:
+        for line_id, line in enumerate(f):
+            split_line = line.split("\t")
+            if len(split_line) != 5:
+                logger.warning("Skipping invalid HindEnCorp line: %s", line)
+                continue
+            yield line_id, {"translation": {"en": split_line[3].strip(), "hi": split_line[4].strip()}}
+
+
+class YakutParser:
+    @staticmethod
+    def create_generator(sub_generator_args=None, config=None):
+        sub_generator = functools.partial(_parse_tsv, language_pair=config.language_pair, skiprows=1)
+        return sub_generator, sub_generator_args
+
+
+class WikititlesV3Parser:
+    @staticmethod
+    def create_generator(sub_generator_args=None, config=None):
+        sub_generator = functools.partial(_parse_tsv, language_pair=config.language_pair)
+        return sub_generator, sub_generator_args