Add Doc.to_disk() and Doc.from_disk() methods

spacy/tokens/doc.pyx

@@ -598,6 +598,24 @@ cdef class Doc:
         self.is_tagged = bool(TAG in attrs or POS in attrs)
         return self
 
+    def to_disk(self, path):
+        """Save the current state to a directory.
+
+        path (unicode or Path): A path to a directory, which will be created if
+            it doesn't exist. Paths may be either strings or `Path`-like objects.
+        """
+        raise NotImplementedError()
+
+    def from_disk(self, path):
+        """Loads state from a directory. Modifies the object in place and
+        returns it.
+
+        path (unicode or Path): A path to a directory. Paths may be either
+            strings or `Path`-like objects.
+        RETURNS (Doc): The modified `Doc` object.
+        """
+        raise NotImplementedError()
+
     def to_bytes(self):
         """Serialize, i.e. export the document contents to a binary string.
 

website/docs/api/doc.jade

@@ -253,6 +253,44 @@ p
         +cell #[code Doc]
         +cell Itself.
 
++h(2, "to_disk") Doc.to_disk
+    +tag method
+
+p Save the current state to a directory.
+
++aside-code("Example").
+    doc.to_disk('/path/to/doc')
+
++table(["Name", "Type", "Description"])
+    +row
+        +cell #[code path]
+        +cell unicode or #[code Path]
+        +cell
+            |  A path to a directory, which will be created if it doesn't exist.
+            |  Paths may be either strings or #[code Path]-like objects.
+
++h(2, "from_disk") Doc.from_disk
+    +tag method
+
+p Loads state from a directory. Modifies the object in place and returns it.
+
++aside-code("Example").
+    from spacy.tokens import Doc
+    doc = Doc().from_disk('/path/to/doc')
+
++table(["Name", "Type", "Description"])
+    +row
+        +cell #[code path]
+        +cell unicode or #[code Path]
+        +cell
+            |  A path to a directory. Paths may be either strings or
+            |  #[code Path]-like objects.
+
+    +footrow
+        +cell returns
+        +cell #[code Doc]
+        +cell The modified #[code Doc] object.
+
 +h(2, "to_bytes") Doc.to_bytes
     +tag method