Merge pull request #1047 from compas-dev/net-tostring

Add ToString to data class

Author: gonzalocasas

CHANGELOG.md

@@ -20,6 +20,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 * Added `Data.guid` to pickle state.
 * Added `Assembly.find_by_key` to locate parts by key.
 * Added `clear_edges` and `clear_nodes` to `NetworkArtist` for ghpython.
+* Added `ToString` method to `Data` to ensure that Rhino/Grasshopper correctly casts objects to string.
 
 ### Changed
 

src/compas/data/data.py

@@ -185,6 +185,18 @@ def data(self):
     def data(self, data):
         raise NotImplementedError
 
+    def ToString(self):
+        """Converts the instance to a string.
+
+        This method exists for .NET compatibility. When using IronPython,
+        the implicit string conversion that usually takes place in CPython
+        will not kick-in, and in its place, IronPython will default to
+        printing self.GetType().FullName or similar. Overriding the `ToString`
+        method of .NET object class fixes that and makes Rhino/Grasshopper
+        display proper string representations when the objects are printed or
+        connected to a panel or other type of string output."""
+        return str(self)
+
     @property
     def jsonstring(self):
         return compas.json_dumps(self.data)

tests/compas/data/test_data.py

@@ -0,0 +1,12 @@
+from compas.data import Data
+
+def test_string_casting():
+    class TestClass(Data):
+        def __init__(self, i):
+            self.i = i
+
+        def __str__(self):
+            return "TestClass {}".format(self.i)
+
+    test = TestClass(42)
+    assert str(test) == "TestClass 42"