Minor code enhancements

tests/test_sheerka_non_reg.py

@@ -427,6 +427,42 @@ def test_i_can_eval_a_mix_with_bnf_and_python_when_rule_name():
     assert res[0].status
     assert res[0].body == 22
 
+    res = sheerka.evaluate_user_input("twenty one + twenty two")
+    assert len(res) == 1
+    assert res[0].status
+    assert res[0].body == 43
+
+    res = sheerka.evaluate_user_input("twenty one + one")
+    assert len(res) == 1
+    assert res[0].status
+    assert res[0].body == 22
+
+
+def test_i_can_eval_a_mix_with_bnf_and_python_when_rule_name_2():
+    sheerka = get_sheerka()
+
+    sheerka.evaluate_user_input("def concept one as 1")
+    sheerka.evaluate_user_input("def concept two as 2")
+    sheerka.evaluate_user_input("def concept twenty as 20")
+    sheerka.evaluate_user_input("def concept twenties from bnf twenty (one | two)=unit as twenty + unit")
+
+    assert sheerka.evaluate_user_input("eval twenty one")[0].body == 21
+
+    res = sheerka.evaluate_user_input("twenty one + 1")
+    assert len(res) == 1
+    assert res[0].status
+    assert res[0].body == 22
+
+    res = sheerka.evaluate_user_input("twenty one + twenty two")
+    assert len(res) == 1
+    assert res[0].status
+    assert res[0].body == 43
+
+    res = sheerka.evaluate_user_input("twenty one + one")
+    assert len(res) == 1
+    assert res[0].status
+    assert res[0].body == 22
+
 
 def test_i_can_eval_a_more_complicated_mix_with_bnf_and_python():
     sheerka = get_sheerka()