Add encoder and decoder to tuple

Author: mverleg

json_tricks/__init__.py

@@ -8,10 +8,10 @@
 from .encoders import TricksEncoder, json_date_time_encode, class_instance_encode, json_complex_encode, \
 	numeric_types_encode, ClassInstanceEncoder, json_set_encode, pandas_encode, nopandas_encode, \
 	numpy_encode, NumpyEncoder, nonumpy_encode, NoNumpyEncoder, fallback_ignore_unknown, pathlib_encode, \
-	bytes_encode, slice_encode
+	bytes_encode, slice_encode, json_tuple_encode
 from .decoders import DuplicateJsonKeyException, TricksPairHook, json_date_time_hook, json_complex_hook, \
 	numeric_types_hook, ClassInstanceHook, json_set_hook, pandas_hook, nopandas_hook, json_numpy_obj_hook, \
-	json_nonumpy_obj_hook, pathlib_hook, json_bytes_hook
+	json_nonumpy_obj_hook, pathlib_hook, json_bytes_hook, json_tuple_hook
 from .nonp import dumps, dump, loads, load
 from ._version import VERSION
 

json_tricks/decoders.py

@@ -212,7 +212,7 @@ def __call__(self, dct, properties=None):
 
 def json_set_hook(dct):
 	"""
-	Return an encoded set to it's python representation.
+	Return an encoded set to its python representation.
 	"""
 	if not isinstance(dct, dict):
 		return dct
@@ -221,6 +221,17 @@ def json_set_hook(dct):
 	return set((tuple(item) if isinstance(item, list) else item) for item in dct['__set__'])
 
 
+def json_tuple_hook(dct):
+	"""
+	Return an encoded tuple to its python representation.
+	"""
+	if not isinstance(dct, dict):
+		return dct
+	if '__tuple__' not in dct:
+		return dct
+	return tuple(dct['__tuple__'])
+
+
 def pandas_hook(dct):
 	if not isinstance(dct, dict):
 		return dct

json_tricks/encoders.py

@@ -331,6 +331,21 @@ def json_set_encode(obj, primitives=False):
 	return obj
 
 
+def json_tuple_encode(obj, primitives=False):
+	"""
+	Encode python tuple as dictionary with key __tuple__ and a list of the values. Preserve order.
+	"""
+	print('is tuple?')  #TODO @mark: TEMPORARY! REMOVE THIS!
+	if isinstance(obj, tuple):
+		print('is tuple!')  #TODO @mark: TEMPORARY! REMOVE THIS!
+		repr = list(obj)
+		if primitives:
+			return repr
+		else:
+			return hashodict(__tuple__=repr)
+	return obj
+
+
 def pandas_encode(obj, primitives=False):
 	from pandas import DataFrame, Series
 	if isinstance(obj, DataFrame):

tests/test_bare.py

@@ -15,6 +15,8 @@
 from _pytest.recwarn import warns
 from pytest import raises, fail
 
+from json_tricks.decoders import json_tuple_hook
+from json_tricks.encoders import json_tuple_encode
 from json_tricks import fallback_ignore_unknown, DuplicateJsonKeyException
 from json_tricks.nonp import strip_comments, dump, dumps, load, loads, \
 	ENCODING
@@ -443,6 +445,33 @@ def test_set():
 	assert setdata[0]['set'] == set(tuple(q) if isinstance(q, list) else q for q in back[0]['set'])
 
 
+def test_tuple():
+	# tuple preserving behaviour is opt-in
+	def assert_values_eq(left, right, *, as_list):
+		assert len(left) == len(right) == 1
+		assert len(left[0]) == len(right[0]) == 1
+		ltup, rtup = left[0]['tup'], right[0]['tup']
+		for i in range(len(left[0]['tup'])):
+			if as_list and (isinstance(ltup[i], list) or isinstance(rtup[i], list)):
+				assert list(ltup[i]) == list(rtup[i])
+			else:
+				assert ltup[i] == rtup[i]
+
+	tupledata = [{'tup': (3, exp(1), (-5, +7), False,)}]
+	json = dumps(tupledata, extra_obj_encoders=())
+	back = loads(json, extra_obj_pairs_hooks=())
+	assert isinstance(back[0]['tup'], list)
+	assert_values_eq(tupledata, back, as_list=True)
+	json = dumps(tupledata, extra_obj_encoders=(json_tuple_encode,))
+	back = loads(json, extra_obj_pairs_hooks=(json_tuple_hook,))
+	assert isinstance(back[0]['tup'], tuple)
+	assert_values_eq(tupledata, back, as_list=True)
+	json = dumps(tupledata, extra_obj_encoders=(json_tuple_encode,), primitives=True)
+	back = loads(json, extra_obj_pairs_hooks=(json_tuple_hook,))
+	assert isinstance(back[0]['tup'], list)
+	assert_values_eq(tupledata, back, as_list=True)
+
+
 def test_special_nr_parsing():
 	nr_li_json = '[1, 3.14]'
 	res = loads(nr_li_json,