define __bool__ on jlwrap objects

Author: Christopher Doris

src/jlwrap/any.jl

@@ -206,6 +206,8 @@ function init_jlwrap_any()
             return ValueBase.__dir__(self) + self._jl_callmethod($(pyjl_methodnum(pyjlany_dir)))
         def __call__(self, *args, **kwargs):
             return self._jl_callmethod($(pyjl_methodnum(pyjlany_call)), args, kwargs)
+        def __bool__(self):
+            return True
         def __len__(self):
             return self._jl_callmethod($(pyjl_methodnum(pyjlany_op(length))))
         def __getitem__(self, k):

src/jlwrap/array.jl

@@ -304,6 +304,8 @@ function init_jlwrap_array()
             return self._jl_callmethod($(pyjl_methodnum(Py ∘ copy)))
         def reshape(self, shape):
             return self._jl_callmethod($(pyjl_methodnum(pyjlarray_reshape)), shape)
+        def __bool__(self):
+            return bool(len(self))
         def __getitem__(self, k):
             return self._jl_callmethod($(pyjl_methodnum(pyjlarray_getitem)), k)
         def __setitem__(self, k, v):

src/jlwrap/dict.jl

@@ -38,6 +38,8 @@ function init_jlwrap_dict()
     class DictValue(AnyValue):
         __slots__ = ()
         _jl_undefined_ = object()
+        def __bool__(self):
+            return bool(len(self))
         def __iter__(self):
             return self._jl_callmethod($(pyjl_methodnum(pyjldict_iter)))
         def __contains__(self, key):

src/jlwrap/set.jl

@@ -79,6 +79,8 @@ function init_jlwrap_set()
     $("\n"^(@__LINE__()-1))
     class SetValue(AnyValue):
         __slots__ = ()
+        def __bool__(self):
+            return bool(len(self))
         def add(self, value):
             return self._jl_callmethod($(pyjl_methodnum(pyjlset_add)), value)
         def discard(self, value):