Add loader script

This commit adds a loader script for the dataset which download data from the original GitHub repository and generate HF dataset

europarl_ner_loader.py

@@ -0,0 +1,137 @@
+# coding=utf-8
+
+"""The HF Datasets adapter for Evaluation Corpus for Named Entity Recognition using Europarl"""
+
+import datasets
+
+_CITATION = """@inproceedings{agerri-etal-2018-building,
+    title = "Building Named Entity Recognition Taggers via Parallel Corpora",
+    author = "Agerri, Rodrigo  and
+      Chung, Yiling  and
+      Aldabe, Itziar  and
+      Aranberri, Nora  and
+      Labaka, Gorka  and
+      Rigau, German",
+    editor = "Calzolari, Nicoletta  and
+      Choukri, Khalid  and
+      Cieri, Christopher  and
+      Declerck, Thierry  and
+      Goggi, Sara  and
+      Hasida, Koiti  and
+      Isahara, Hitoshi  and
+      Maegaard, Bente  and
+      Mariani, Joseph  and
+      Mazo, H{\'e}l{\`e}ne  and
+      Moreno, Asuncion  and
+      Odijk, Jan  and
+      Piperidis, Stelios  and
+      Tokunaga, Takenobu",
+    booktitle = "Proceedings of the Eleventh International Conference on Language Resources and Evaluation ({LREC} 2018)",
+    month = may,
+    year = "2018",
+    address = "Miyazaki, Japan",
+    publisher = "European Language Resources Association (ELRA)",
+    url = "https://aclanthology.org/L18-1557",
+}"""
+
+_DESCRIPTION = """This dataset contains a gold-standard test set created from the
+Europarl corpus. The test set consists of 799 sentences manually annotated using
+four entity types and following the CoNLL 2002 and 2003 guidelines for 4 languages:
+English, German, Italian and Spanish."""
+
+_DATA_URLs = {
+    "en": "https://github.com/ixa-ehu/ner-evaluation-corpus-europarl/raw/master/en-europarl.test.conll02",
+    "de": "https://github.com/ixa-ehu/ner-evaluation-corpus-europarl/raw/master/de-europarl.test.conll02",
+    "es": "https://github.com/ixa-ehu/ner-evaluation-corpus-europarl/raw/master/es-europarl.test.conll02",
+    "it": "https://github.com/ixa-ehu/ner-evaluation-corpus-europarl/raw/master/it-europarl.test.conll02",
+}
+_HOMEPAGE = "https://github.com/ixa-ehu/ner-evaluation-corpus-europarl"
+_VERSION = "1.0.0"
+_LANGS = ["en", "de", "es", "it"]
+
+
+class EuroparlNERConfig(datasets.BuilderConfig):
+    def __init__(self, **kwargs):
+        super(EuroparlNERConfig, self).__init__(
+            version=datasets.Version(_VERSION, ""), **kwargs
+        )
+
+
+class EuroparlNER(datasets.GeneratorBasedBuilder):
+    """EuroparlNER is a multilingual named entity recognition dataset consisting of
+    manualy anotated part of the European Parliament Proceedings Parallel Corpus
+    1996-2011 with LOC, PER, ORG and MISC tags"""
+
+    VERSION = datasets.Version(_VERSION)
+    BUILDER_CONFIGS = [
+        EuroparlNERConfig(
+            name=lang, description=f"EuroparlNER examples in language {lang}"
+        )
+        for lang in _LANGS
+    ]
+    DEFAULT_CONFIG_NAME = "en"
+
+    def _info(self):
+        features = datasets.Features(
+            {
+                "tokens": datasets.Sequence(datasets.Value("string")),
+                "ner_tags": datasets.Sequence(
+                    datasets.features.ClassLabel(
+                        names=[
+                            "O",
+                            "B-PER",
+                            "I-PER",
+                            "B-ORG",
+                            "I-ORG",
+                            "B-LOC",
+                            "I-LOC",
+                            "B-MISC",
+                            "I-MISC",
+                        ]
+                    )
+                ),
+            }
+        )
+        return datasets.DatasetInfo(
+            description=_DESCRIPTION,
+            features=features,
+            supervised_keys=None,
+            homepage=_HOMEPAGE,
+            citation=_CITATION,
+        )
+
+    def _split_generators(self, dl_manager):
+        lang = self.config.name
+        dl_dir = dl_manager.download(_DATA_URLs[lang])
+
+        return [
+            datasets.SplitGenerator(
+                name=datasets.Split.TEST,
+                gen_kwargs={"filepath": dl_dir},
+            ),
+        ]
+
+    def _generate_examples(self, filepath):
+        guid_index = 1
+        with open(filepath, encoding="utf-8") as f:
+            tokens = []
+            ner_tags = []
+            for line in f:
+                if line == "" or line == "\n":
+                    if tokens:
+                        yield guid_index, {
+                            "tokens": tokens,
+                            "ner_tags": ner_tags,
+                        }
+                        guid_index += 1
+                        tokens = []
+                        ner_tags = []
+                else:
+                    # EuroparlNER data is tab separated
+                    splits = line.split("\t")
+                    tokens.append(splits[0])
+                    if len(splits) > 1:
+                        ner_tags.append(splits[1].replace("\n", ""))
+                    else:
+                        # examples have no label in test set
+                        ner_tags.append("O")