PYON: add plugin-based encode/decode

Author: drewrisinger

sipyco/pyon.py

@@ -14,18 +14,24 @@
 that JSON does not support Numpy and more generally cannot be extended with
 other data types while keeping a concise syntax. Here we can use the Python
 function call syntax to express special data types.
-"""
 
+PYON can be extended via encoding & decoding plugins to whatever types you would like to serialize.
+An example can be found in :mod:`sipyco.test.test_pyon_plugin`.
+"""
 
+import itertools
+import os
+import tempfile
 from operator import itemgetter
 from fractions import Fraction
 from collections import OrderedDict
-import os
-import tempfile
 
 import numpy
 import pybase64 as base64
 
+import sipyco
+import sipyco.plugins as plugin
+
 
 _encode_map = {
     type(None): "none",
@@ -171,10 +177,28 @@ def encode(self, x):
         return getattr(self, "encode_" + ty)(x)
 
 
-def encode(x, pretty=False):
+@sipyco.hookimpl
+def sipyco_pyon_encode(value, pretty=False, indent_level=0):
+    """Default PYON encoder implementation."""
+    try:
+        return _Encoder(pretty=pretty, indent_level=indent_level).encode(value)
+    except TypeError:
+        return None
+
+
+def encode(x, pretty=False, indent_level=0):
     """Serializes a Python object and returns the corresponding string in
     Python syntax."""
-    return _Encoder(pretty).encode(x)
+    pm = plugin.get_plugin_manager()
+
+    func_val = pm.hook.sipyco_pyon_encode(
+        value=x, pretty=pretty, indent_level=indent_level
+    )
+
+    if func_val is None:
+        raise TypeError("`{!r}` ({}) is not PYON serializable".format(x, type(x)))
+    else:
+        return func_val
 
 
 def _nparray(shape, dtype, data):
@@ -204,10 +228,22 @@ def _npscalar(ty, data):
 }
 
 
+@sipyco.hookimpl
+def sipyco_pyon_decoders():
+    """Default Sipyco PYON decoding valid types."""
+    return _eval_dict.items()
+
+
 def decode(s):
     """Parses a string in the Python syntax, reconstructs the corresponding
     object, and returns it."""
-    return eval(s, _eval_dict, {})
+    pm = plugin.get_plugin_manager()
+    _decode_eval_dict = dict(
+        itertools.chain.from_iterable(
+            filter(lambda r: r is not None, pm.hook.sipyco_pyon_decoders())
+        )
+    )
+    return eval(s, _decode_eval_dict, {})
 
 
 def store_file(filename, x):

sipyco/test/test_pyon_plugin.py

@@ -0,0 +1,52 @@
+import dataclasses
+
+import pluggy
+import pytest
+
+import sipyco
+import sipyco.hookspecs as hookspecs
+import sipyco.plugins as plugin
+import sipyco.pyon as pyon
+
+
+@dataclasses.dataclass
+class Point:
+    x: float
+    y: float
+
+
+class TestPyonPlugin:
+    @sipyco.hookimpl
+    def sipyco_pyon_encode(value, pretty=False):
+        # breakpoint()
+        if isinstance(value, Point):
+            return repr(value)
+
+    @sipyco.hookimpl
+    def sipyco_pyon_decoders():
+        return [("Point", Point)]
+
+
+def test_pyon_plugin_fail_without_plugin():
+    with pytest.raises(TypeError):
+        pyon.encode(Point(3, 4))
+
+
+def pyon_extra_plugin():
+    pm = pluggy.PluginManager("sipyco")
+    pm.add_hookspecs(sipyco.hookspecs)
+    pm.register(pyon)
+    pm.load_setuptools_entrypoints("sipyco")
+    pm.register(TestPyonPlugin)
+    return pm
+
+
+def test_pyon_plugin_encode(monkeypatch):
+    monkeypatch.setattr(plugin, "get_plugin_manager", pyon_extra_plugin)
+    assert pyon.encode(Point(2, 3)) == "Point(x=2, y=3)"
+
+
+def test_pyon_plugin_encode_decode(monkeypatch):
+    monkeypatch.setattr(plugin, "get_plugin_manager", pyon_extra_plugin)
+    test_value = Point(2.5, 3.4)
+    assert pyon.decode(pyon.encode(test_value)) == test_value