Add support for NaN constants and NaN defaults in ROS IDL

rosidl_adapter/test/test_constant.py

@@ -12,6 +12,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import math
+
 import pytest
 
 from rosidl_adapter.parser import Constant
@@ -30,6 +32,11 @@ def test_constant_constructor():
     with pytest.raises(ValueError):
         Constant('bool', 'FOO', None)
 
+    # NaN is case insensitive in python, so test a few variations.
+    for nan_string in ['nan', 'Nan', 'NaN', 'NAN', 'nan', 'Nan', 'NaN', 'NAN']:
+        value = Constant('float32', 'FOO', nan_string)
+        assert math.isnan(value.value)
+
 
 def test_constant_methods():
     assert Constant('bool', 'FOO', '1') != 23

rosidl_generator_c/resource/idl__struct.h.em

@@ -32,10 +32,10 @@ extern "C"
 {
 #endif
 
+#include <math.h>
 #include <stdbool.h>
 #include <stddef.h>
 #include <stdint.h>
-
 @#######################################################################
 @# Handle message
 @#######################################################################

rosidl_generator_c/rosidl_generator_c/__init__.py

@@ -11,6 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+from math import isnan
 
 from typing import List
 
@@ -211,10 +212,16 @@ def basic_value_to_c(type_, value):
         return f'{value}ull'
 
     if 'float' == type_.typename:
-        return f'{value}f'
+        if isnan(float(value)):
+            return 'nanf(\"\")'
+        else:
+            return f'{value}f'
 
     if 'double' == type_.typename:
-        return f'{value}l'
+        if isnan(float(value)):
+            return 'nan(\"\")'
+        else:
+            return f'{value}l'
 
     assert False, "unknown basic type '%s'" % type_
 

rosidl_generator_cpp/resource/idl__struct.hpp.em

@@ -28,6 +28,7 @@ include_directives = set()
 
 #include <algorithm>
 #include <array>
+#include <limits>
 #include <memory>
 #include <string>
 #include <vector>

rosidl_generator_cpp/resource/msg__struct.hpp.em

@@ -286,8 +286,12 @@ non_defaulted_zero_initialized_members = [
 @[    if constant.type.typename in UNSIGNED_INTEGER_TYPES]@
 u@
 @[    end if]@
-@[   elif constant.type.typename == 'float']@
-    @(constant.value)f@
+@[   elif constant.type.typename == 'float' or constant.type.typename == 'double']@
+@{
+from rosidl_generator_cpp import primitive_value_to_cpp
+val = primitive_value_to_cpp(constant.type, constant.value)
+}@
+    @(val)@
 @[   else]@
     @(constant.value)@
 @[   end if];

rosidl_generator_cpp/rosidl_generator_cpp/__init__.py

@@ -13,6 +13,7 @@
 # limitations under the License.
 
 from ast import literal_eval
+from math import isnan
 from typing import List
 
 from rosidl_parser.definition import AbstractGenericString
@@ -196,6 +197,11 @@ def primitive_value_to_cpp(type_, value):
     if type_.typename == 'boolean':
         return 'true' if value else 'false'
 
+    if type_.typename in ['double', 'long double', 'float']:
+        # Handle special floating types here.
+        if isnan(float(value)):
+            return f'std::numeric_limits<{type_.typename}>::quiet_NaN()'
+
     if type_.typename in [
         'short', 'unsigned short',
         'char', 'wchar',

rosidl_generator_tests/CMakeLists.txt

@@ -35,6 +35,8 @@ if(BUILD_TESTING)
     ${test_interface_files_MSG_FILES}
     ${test_interface_files_SRV_FILES}
     msg/BasicIdl.idl
+    msg/NanValueConstant.msg
+    msg/NanValueDefault.msg
     msg/SmallConstant.msg
     ADD_LINTER_TESTS
     SKIP_INSTALL

rosidl_generator_tests/msg/NanValueConstant.msg

@@ -0,0 +1,2 @@
+float32 FLOAT32_NAN=NaN
+float64 FLOAT64_NAN=nan

rosidl_generator_tests/msg/NanValueDefault.msg

@@ -0,0 +1,2 @@
+float32 float32_nan NaN
+float64 float64_nan nan

rosidl_generator_tests/test/rosidl_generator_cpp/test_interfaces.cpp

@@ -41,6 +41,8 @@
 #include "rosidl_generator_tests/msg/multi_nested.hpp"
 #include "rosidl_generator_tests/msg/nested.hpp"
 #include "rosidl_generator_tests/msg/small_constant.hpp"
+#include "rosidl_generator_tests/msg/nan_value_constant.hpp"
+#include "rosidl_generator_tests/msg/nan_value_default.hpp"
 #include "rosidl_generator_tests/msg/strings.hpp"
 #include "rosidl_generator_tests/msg/unbounded_sequences.hpp"
 #include "rosidl_generator_tests/msg/w_strings.hpp"
@@ -483,6 +485,11 @@ TEST(Test_messages, constants_assign) {
   ASSERT_EQ(x, rosidl_generator_tests::msg::SmallConstant::FLOAT32_CONST);
 }
 
+TEST(Test_messages, nan_constants) {
+  ASSERT_TRUE(std::isnan(rosidl_generator_tests::msg::NanValueConstant::FLOAT32_NAN));
+  ASSERT_TRUE(std::isnan(rosidl_generator_tests::msg::NanValueConstant::FLOAT64_NAN));
+}
+
 // Defaults
 TEST(Test_messages, defaults) {
   rosidl_generator_tests::msg::Defaults message;
@@ -501,6 +508,12 @@ TEST(Test_messages, defaults) {
   TEST_BASIC_TYPE_FIELD_ASSIGNMENT(message, uint64_value, 50000000ull, UINT64_MAX);
 }
 
+TEST(Test_messages, nan_defaults) {
+  rosidl_generator_tests::msg::NanValueDefault nan_val_default;
+  ASSERT_TRUE(std::isnan(nan_val_default.float32_nan));
+  ASSERT_TRUE(std::isnan(nan_val_default.float64_nan));
+}
+
 // String array with default values
 TEST(Test_messages, string_arrays_default) {
   rosidl_generator_tests::msg::Arrays message;