fix dataset

fastNLP/api/parser.py

@@ -3,6 +3,7 @@ from fastNLP.core.dataset import DataSet
 from fastNLP.core.predictor import Predictor
 from fastNLP.api.pipeline import Pipeline
 from fastNLP.api.processor import *
+from fastNLP.models.biaffine_parser import BiaffineParser
 
 
 class DependencyParser(API):
@@ -23,9 +24,13 @@ class DependencyParser(API):
     def build(self):
         pipe = Pipeline()
 
+        # build pipeline
         word_seq = 'word_seq'
         pos_seq = 'pos_seq'
-        pipe.add_processor(Num2TagProcessor('<NUM>', word_seq))
+        pipe.add_processor(Num2TagProcessor('<NUM>', 'raw_sentence', word_seq))
         pipe.add_processor(IndexerProcessor(word_vocab, word_seq, word_seq+'_idx'))
         pipe.add_processor(IndexerProcessor(pos_vocab, pos_seq, pos_seq+'_idx'))
-        pipe.add_processor()
+
+        # load model parameters
+        self.model = BiaffineParser()
+        self.pipeline = pipe

fastNLP/core/dataset.py

@@ -86,6 +86,8 @@ class DataSet(object):
         return self.field_arrays[name]
 
     def __len__(self):
+        if len(self.field_arrays) == 0:
+            return 0
         field = iter(self.field_arrays.values()).__next__()
         return len(field)