Implement Symbol as Text in C-extension

amazon/ion/ioncmodule.c

@@ -1075,7 +1075,10 @@ static void ionc_add_to_container(PyObject* pyContainer, PyObject* element, BOOL
  */
 iERR ionc_read_value(hREADER hreader, ION_TYPE t, PyObject* container, BOOL in_struct, uint8_t value_model) {
     iENTER;
-    BOOL        wrap_py_value = !value_model;
+
+    BOOL        wrap_py_value = !(value_model & 1);
+    BOOL        symbol_as_text = value_model & 2;
+
     BOOL        is_null;
     ION_STRING  field_name;
     SIZE        annotation_count;
@@ -1219,8 +1222,15 @@ iERR ionc_read_value(hREADER hreader, ION_TYPE t, PyObject* container, BOOL in_s
         {
             ION_STRING string_value;
             IONCHECK(ion_reader_read_string(hreader, &string_value));
-            py_value = ion_string_to_py_symboltoken(&string_value);
-            ion_nature_constructor = _ionpysymbol_fromvalue;
+            if (!symbol_as_text) {
+                py_value = ion_string_to_py_symboltoken(&string_value);
+                ion_nature_constructor = _ionpysymbol_fromvalue;
+            } else if (ion_string_is_null(&string_value)) {
+                _FAILWITHMSG(IERR_INVALID_STATE, "Cannot emit symbol with undefined text when SYMBOL_AS_TEXT is set.");
+            } else {
+                py_value = ion_build_py_string(&string_value);
+                ion_nature_constructor = _ionpytext_fromvalue;
+            }
             break;
         }
         case tid_STRING_INT:
@@ -1475,8 +1485,8 @@ PyObject* ionc_read(PyObject* self, PyObject *args, PyObject *kwds) {
                                      &value_model, &text_buffer_size_limit)) {
         FAILWITH(IERR_INVALID_ARG);
     }
-    if (value_model > 1) {
-        FAILWITHMSG(IERR_INVALID_ARG, "Only ION_PY and MIXED value models are currently supported!")
+    if (value_model > 3) {
+        _FAILWITHMSG(IERR_INVALID_ARG, "Only ION_PY, MAY_BE_BARE and SYMBOL_AS_TEXT value models are currently supported!")
     }
 
     iterator = PyObject_New(ionc_read_Iterator, &ionc_read_IteratorType);

tests/test_simpleion.py

@@ -741,22 +741,51 @@ def test_bare_values(params):
         assert ion_equals(value, expectation)
 
 
-def test_value_models_flags():
+@parametrize(
+    ("foo", IonPyValueModel.ION_PY, IonPySymbol),
+    ("foo", IonPyValueModel.MAY_BE_BARE, SymbolToken),
+    ("foo", IonPyValueModel.SYMBOL_AS_TEXT, IonPyText, IonType.SYMBOL),
+    ("foo", IonPyValueModel.MAY_BE_BARE | IonPyValueModel.SYMBOL_AS_TEXT, str),
+    ("foo::bar", IonPyValueModel.MAY_BE_BARE, IonPySymbol),
+    ("foo::bar", IonPyValueModel.MAY_BE_BARE | IonPyValueModel.SYMBOL_AS_TEXT, IonPyText, IonType.SYMBOL),
+)
+def test_value_model_flags(params):
     # This function only tests c extension
     if not c_ext:
         return
 
-    ion_text = "31"
-    value = simpleion.load_extension(StringIO(ion_text), value_model=IonPyValueModel.ION_PY)
-    assert type(value) is IonPyInt
-    value = simpleion.load_extension(StringIO(ion_text), value_model=IonPyValueModel.MAY_BE_BARE)
-    assert type(value) is int
+    if len(params) == 3:
+        ion_text, value_model, expected_type = params
+        expected_ion_type = None
+    else:
+        ion_text, value_model, expected_type, expected_ion_type = params
 
-    try:
+    value = simpleion.load_extension(StringIO(ion_text), value_model=value_model)
+    assert type(value) is expected_type
+    if expected_ion_type:
+        assert value.ion_type == expected_ion_type
+
+
+def test_undefined_symbol_text_as_text():
+    # This function only tests c extension
+    if not c_ext:
+        return
+
+    ion_text = """
+    $ion_symbol_table::{ symbols:[ null ] }
+    $10
+    """
+    with raises(IonException, match="Cannot emit symbol with undefined text"):
         simpleion.load_extension(StringIO(ion_text), value_model=IonPyValueModel.SYMBOL_AS_TEXT)
-        assert False
-    except:
-        pass
+
+
+def test_invalid_value_model_flag():
+    # This function only tests c extension
+    if not c_ext:
+        return
+
+    with raises(IonException, match="value models are currently supported"):
+        simpleion.load_extension(StringIO("foo"), value_model=IonPyValueModel.STRUCT_AS_STD_DICT)
 
 
 # See issue https://github.com/amazon-ion/ion-python/issues/232