Add remove_extension method on Doc, Token and Span (closes #2242)

spacy/tests/test_underscore.py

@@ -60,6 +60,15 @@ def test_token_underscore_method():
     assert token._.hello() == 'cheese'
 
 
+@pytest.mark.parametrize('obj', [Doc, Span, Token])
+def test_doc_underscore_remove_extension(obj):
+    ext_name = 'to_be_removed'
+    obj.set_extension(ext_name, default=False)
+    assert obj.has_extension(ext_name)
+    obj.remove_extension(ext_name)
+    assert not obj.has_extension(ext_name)
+
+
 @pytest.mark.parametrize('obj', [Doc, Span, Token])
 def test_underscore_raises_for_dup(obj):
     obj.set_extension('test', default=None)

spacy/tokens/doc.pyx

@@ -108,6 +108,12 @@ cdef class Doc:
     def has_extension(cls, name):
         return name in Underscore.doc_extensions
 
+    @classmethod
+    def remove_extension(cls, name):
+        if not cls.has_extension(name):
+            raise ValueError(Errors.E046.format(name=name))
+        return Underscore.doc_extensions.pop(name)
+
     def __init__(self, Vocab vocab, words=None, spaces=None, user_data=None,
                  orths_and_spaces=None):
         """Create a Doc object.

spacy/tokens/span.pyx

@@ -36,6 +36,12 @@ cdef class Span:
     def has_extension(cls, name):
         return name in Underscore.span_extensions
 
+    @classmethod
+    def remove_extension(cls, name):
+        if not cls.has_extension(name):
+            raise ValueError(Errors.E046.format(name=name))
+        return Underscore.span_extensions.pop(name)
+
     def __cinit__(self, Doc doc, int start, int end, attr_t label=0,
                   vector=None, vector_norm=None):
         """Create a `Span` object from the slice `doc[start : end]`.

spacy/tokens/token.pyx

@@ -41,6 +41,12 @@ cdef class Token:
     def has_extension(cls, name):
         return name in Underscore.token_extensions
 
+    @classmethod
+    def remove_extension(cls, name):
+        if not cls.has_extension(name):
+            raise ValueError(Errors.E046.format(name=name))
+        return Underscore.token_extensions.pop(name)
+
     def __cinit__(self, Vocab vocab, Doc doc, int offset):
         """Construct a `Token` object.