Clean up FunctionGraph str and repr implementation

tests/gof/test_destroyhandler.py

@@ -144,12 +144,12 @@ def test_misc():
     g = Env([x, y, z], [e])
     assert g.consistent()
     PatternOptimizer((transpose_view, (transpose_view, "x")), "x").optimize(g)
-    assert str(g) == "[x]"
+    assert str(g) == "FunctionGraph(x)"
     new_e = add(x, y)
     g.replace_validate(x, new_e)
-    assert str(g) == "[Add(x, y)]"
+    assert str(g) == "FunctionGraph(Add(x, y))"
     g.replace(new_e, dot(add_in_place(x, y), transpose_view(x)))
-    assert str(g) == "[Dot(AddInPlace(x, y), TransposeView(x))]"
+    assert str(g) == "FunctionGraph(Dot(AddInPlace(x, y), TransposeView(x)))"
     assert not g.consistent()
 
 
@@ -325,7 +325,10 @@ def test_long_destroyers_loop():
     OpSubOptimizer(add, add_in_place).optimize(g)
     assert g.consistent()
     # we don't want to see that!
-    assert str(g) != "[Dot(Dot(AddInPlace(x, y), AddInPlace(y, z)), AddInPlace(z, x))]"
+    assert (
+        str(g)
+        != "FunctionGraph(Dot(Dot(AddInPlace(x, y), AddInPlace(y, z)), AddInPlace(z, x)))"
+    )
     e2 = dot(dot(add_in_place(x, y), add_in_place(y, z)), add_in_place(z, x))
     with pytest.raises(InconsistencyError):
         Env(*graph.clone([x, y, z], [e2]))

tests/scalar/test_basic.py

@@ -173,12 +173,12 @@ class TestComposite:
         gof.DualLinker().accept(g).make_function()
 
         assert str(g) == (
-            "[*1 -> Composite{((i0 + i1) + i2),"
+            "FunctionGraph(*1 -> Composite{((i0 + i1) + i2),"
             " (i0 + (i1 * i2)), (i0 / i1), "
             "(i0 // Constant{5}), "
             "(-i0), (i0 - i1), ((i0 ** i1) + (-i2)),"
             " (i0 % Constant{3})}(x, y, z), "
-            "*1::1, *1::2, *1::3, *1::4, *1::5, *1::6, *1::7]"
+            "*1::1, *1::2, *1::3, *1::4, *1::5, *1::6, *1::7)"
         )
 
     def test_make_node_continue_graph(self):

theano/gof/fg.py

@@ -812,11 +812,8 @@ class FunctionGraph(utils.object2):
                         "Inconsistent clients list.", variable, node.inputs[i]
                     )
 
-    def __str__(self):
-        return f"[{', '.join(graph.as_string(self.inputs, self.outputs))}]"
-
     def __repr__(self):
-        return self.__str__()
+        return f"FunctionGraph({', '.join(graph.as_string(self.inputs, self.outputs))})"
 
     def clone(self, check_integrity=True):
         """