Fix serialization of System.Decimal data type

Author: gonzalocasas

CHANGELOG.md

@@ -17,6 +17,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 * Fixed Grasshopper `draw_polylines` method to return `PolylineCurve` instead of `Polyline` because the latter shows as only points.
 * Fixed uninstall post-process.
 * Fixed `area_polygon` that was, in some cases, returning a negative area
+* Fixed support for `System.Decimal` data type on json serialization.
 
 ### Removed
 

src/compas/data/encoders.py

@@ -8,14 +8,26 @@
 
 from compas.data.exceptions import DecoderError
 
+IDictionary = None
+numpy_support = False
+dotnet_support = False
+
 # We don't do this from `compas.IPY` to avoid circular imports
 if "ironpython" == platform.python_implementation().lower():
+    dotnet_support = True
+
     try:
+        import System
         from System.Collections.Generic import IDictionary
     except:  # noqa: E722
-        IDictionary = None
-else:
-    IDictionary = None
+        pass
+
+try:
+    import numpy as np
+
+    numpy_support = True
+except ImportError:
+    numpy_support = False
 
 
 def cls_from_dtype(dtype):
@@ -113,11 +125,7 @@ def default(self, o):
         if hasattr(o, "__next__"):
             return list(o)
 
-        try:
-            import numpy as np
-        except ImportError:
-            pass
-        else:
+        if numpy_support:
             if isinstance(o, np.ndarray):
                 return o.tolist()
             if isinstance(
@@ -144,6 +152,10 @@ def default(self, o):
             if isinstance(o, np.void):
                 return None
 
+        if dotnet_support:
+            if isinstance(o, System.Decimal):
+                return float(o)
+
         return super(DataEncoder, self).default(o)