Type casting functions to classes to support type checking.

src/scenic/syntax/veneer.py

@@ -2074,24 +2074,27 @@ def helper(context):
 # functions seems to break pickling/unpickling
 
 
-@distributionFunction
-def filter(function, iterable):
-    return list(builtins.filter(function, iterable))
+class str(str):
+    @distributionFunction
+    def __call__(*args, **kwargs):
+        return builtins.str(*args, **kwargs)
 
 
-@distributionFunction
-def str(*args, **kwargs):
-    return builtins.str(*args, **kwargs)
+class float(float):
+    @distributionFunction
+    def __call__(*args, **kwargs):
+        return builtins.float(*args, **kwargs)
 
 
-@distributionFunction
-def float(*args, **kwargs):
-    return builtins.float(*args, **kwargs)
+class int(int):
+    @distributionFunction
+    def __call__(*args, **kwargs):
+        return builtins.int(*args, **kwargs)
 
 
 @distributionFunction
-def int(*args, **kwargs):
-    return builtins.int(*args, **kwargs)
+def filter(function, iterable):
+    return list(builtins.filter(function, iterable))
 
 
 @distributionFunction

tests/syntax/test_typing.py

@@ -63,3 +63,36 @@ def test_list_as_vector_3():
             param p = distance to [-2, -2, 0, 6]
             """
         )
+
+
+# isinstance Tests
+
+
+def test_isinstance_str():
+    p = sampleParamPFrom(
+        """
+        param p = str(1)
+        assert isinstance(globalParameters.p, str)
+        """
+    )
+    assert isinstance(p, str)
+
+
+def test_isinstance_float():
+    p = sampleParamPFrom(
+        """
+        param p = float(1)
+        assert isinstance(globalParameters.p, float)
+        """
+    )
+    assert isinstance(p, float)
+
+
+def test_isinstance_int():
+    p = sampleParamPFrom(
+        """
+        param p = int(1.5)
+        assert isinstance(globalParameters.p, int)
+        """
+    )
+    assert isinstance(p, int)