Enforce static parameter types

rclcpp/include/rclcpp/node.hpp

@@ -311,8 +311,24 @@ class Node : public std::enable_shared_from_this<Node>
   declare_parameter(
     const std::string & name,
     const rclcpp::ParameterValue & default_value = rclcpp::ParameterValue(),
+    const rclcpp::ParameterDescriptor & parameter_descriptor =
+    rclcpp::ParameterDescriptor(),
+    bool ignore_override = false);
+
+  /// Declare and initialize a parameter, return the effective value.
+  /**
+   * Same as:
+   * ```cpp
+   * node.declare_parameter(name, ParameterValue{}, descriptor, ignore_override);
+   * ```
+   */
+  RCLCPP_PUBLIC
+  const rclcpp::ParameterValue &
+  declare_parameter(
+    const std::string & name,
+    rclcpp::ParameterType type,
     const rcl_interfaces::msg::ParameterDescriptor & parameter_descriptor =
-    rcl_interfaces::msg::ParameterDescriptor(),
+    rcl_interfaces::msg::ParameterDescriptor{},
     bool ignore_override = false);
 
   /// Declare and initialize a parameter with a type.
@@ -341,8 +357,8 @@ class Node : public std::enable_shared_from_this<Node>
   declare_parameter(
     const std::string & name,
     const ParameterT & default_value,
-    const rcl_interfaces::msg::ParameterDescriptor & parameter_descriptor =
-    rcl_interfaces::msg::ParameterDescriptor(),
+    const rclcpp::ParameterDescriptor & parameter_descriptor =
+    rclcpp::ParameterDescriptor(),
     bool ignore_override = false);
 
   /// Declare and initialize several parameters with the same namespace and type.
@@ -401,7 +417,7 @@ class Node : public std::enable_shared_from_this<Node>
     const std::string & namespace_,
     const std::map<
       std::string,
-      std::pair<ParameterT, rcl_interfaces::msg::ParameterDescriptor>
+      std::pair<ParameterT, rclcpp::ParameterDescriptor>
     > & parameters,
     bool ignore_overrides = false);
 

rclcpp/include/rclcpp/node_impl.hpp

@@ -157,7 +157,7 @@ auto
 Node::declare_parameter(
   const std::string & name,
   const ParameterT & default_value,
-  const rcl_interfaces::msg::ParameterDescriptor & parameter_descriptor,
+  const rclcpp::ParameterDescriptor & parameter_descriptor,
   bool ignore_override)
 {
   try {
@@ -187,7 +187,7 @@ Node::declare_parameters(
       return this->declare_parameter(
         normalized_namespace + element.first,
         element.second,
-        rcl_interfaces::msg::ParameterDescriptor(),
+        rclcpp::ParameterDescriptor(),
         ignore_overrides);
     }
   );
@@ -200,7 +200,7 @@ Node::declare_parameters(
   const std::string & namespace_,
   const std::map<
     std::string,
-    std::pair<ParameterT, rcl_interfaces::msg::ParameterDescriptor>
+    std::pair<ParameterT, rclcpp::ParameterDescriptor>
   > & parameters,
   bool ignore_overrides)
 {

rclcpp/include/rclcpp/node_interfaces/node_parameters.hpp

@@ -108,8 +108,17 @@ class NodeParameters : public NodeParametersInterface
   declare_parameter(
     const std::string & name,
     const rclcpp::ParameterValue & default_value,
-    const rcl_interfaces::msg::ParameterDescriptor & parameter_descriptor,
-    bool ignore_override) override;
+    const rclcpp::ParameterDescriptor & parameter_descriptor,
+    bool ignore_override = false) override;
+
+  RCLCPP_PUBLIC
+  const rclcpp::ParameterValue &
+  declare_parameter(
+    const std::string & name,
+    rclcpp::ParameterType type,
+    rcl_interfaces::msg::ParameterDescriptor parameter_descriptor =
+    rcl_interfaces::msg::ParameterDescriptor(),
+    bool ignore_override = false) override;
 
   RCLCPP_PUBLIC
   void

rclcpp/include/rclcpp/node_interfaces/node_parameters_interface.hpp

@@ -26,6 +26,7 @@
 
 #include "rclcpp/macros.hpp"
 #include "rclcpp/parameter.hpp"
+#include "rclcpp/parameter_descriptor.hpp"
 #include "rclcpp/visibility_control.hpp"
 
 namespace rclcpp
@@ -65,7 +66,21 @@ class NodeParametersInterface
   declare_parameter(
     const std::string & name,
     const rclcpp::ParameterValue & default_value = rclcpp::ParameterValue(),
-    const rcl_interfaces::msg::ParameterDescriptor & parameter_descriptor =
+    const rclcpp::ParameterDescriptor & parameter_descriptor =
+    rclcpp::ParameterDescriptor(),
+    bool ignore_override = false) = 0;
+
+  /// Declare and initialize a parameter.
+  /**
+   * \sa rclcpp::Node::declare_parameter
+   */
+  RCLCPP_PUBLIC
+  virtual
+  const rclcpp::ParameterValue &
+  declare_parameter(
+    const std::string & name,
+    rclcpp::ParameterType type,
+    rcl_interfaces::msg::ParameterDescriptor parameter_descriptor =
     rcl_interfaces::msg::ParameterDescriptor(),
     bool ignore_override = false) = 0;
 

rclcpp/include/rclcpp/parameter_descriptor.hpp

@@ -0,0 +1,90 @@
+// Copyright 2020 Open Source Robotics Foundation, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// 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.
+
+#ifndef RCLCPP__PARAMETER_DESCRIPTOR_HPP_
+#define RCLCPP__PARAMETER_DESCRIPTOR_HPP_
+
+namespace rclcpp
+{
+
+/// rcl_interfaces::msg::ParameterDescriptor wrapper used to streamline parameter declarations.
+/**
+ * Examples:
+ * ```cpp
+ * // declare statically typed parameter, type inferred from gived default value
+ * node.declare_parameter("my_int", 5);
+ *
+ * // declare statically typed parameter, no default value given.
+ * node.declare_parameter(
+ *   "my_int", rclcpp::ParameterType::INTEGER_PARAMETER);
+ *
+ * // declare statically typed parameter, type inferred from given default, with descriptor.
+ * rcl_interfaces::msg::ParameterDescriptor descriptor;
+ * //>> Set descriptor <<
+ * node.declare_parameter("my_int", 5, descriptor);
+ *
+ * // declare statically typed parameter, type inferred from descriptor.
+ * rcl_interfaces::msg::ParameterDescriptor descriptor;
+ * descriptor.allowed_type = static_cast<uint8_t>(rclcpp::ParameterType::INTEGER_PARAMETER);
+ * //>> Set other things in descriptor.<<
+ * node.declare_parameter("my_int", {descriptor, false});
+ *
+ * // declare parameter that can change of type
+ * node.declare_parameter("my_param", rclcpp::ParameterType::PARAMETER_NOT_SET);
+ *
+ * // declare parameter that can change of type with default value
+ * node.declare_parameter("my_param", 5, rclcpp::ParameterDescriptor{false});
+ *
+ * // declare parameter that can change of type with default value and descriptor
+ * rcl_interfaces::msg::ParameterDescriptor descriptor;
+ * //>> Set descriptor <<
+ * node.declare_parameter("my_param", 5, {descriptor, false});
+ */
+class ParameterDescriptor
+{
+public:
+  /// Default constructor.
+  explicit ParameterDescriptor(bool infer_type_from_value = true)
+  : infer_type_from_value_{infer_type_from_value} {}
+
+  /// Implicit constructor from parameter descriptor message.
+  ParameterDescriptor(
+    const rcl_interfaces::msg::ParameterDescriptor & msg, bool infer_type_from_value = true)
+  // NOLINT: implicit conversion constructor
+  : impl_(msg), infer_type_from_value_{infer_type_from_value} {}
+
+  /// Getter of internal message representation.
+  rcl_interfaces::msg::ParameterDescriptor &
+  get_msg()
+  {return impl_;}
+
+  /// Getter of internal message representation.
+  const rcl_interfaces::msg::ParameterDescriptor &
+  get_msg() const
+  {return impl_;}
+
+  /// Return true if we have to ignore the allowed type provided in the descriptor and infer
+  /// it later from the default value.
+  bool
+  do_infer_type_from_value() const
+  {return infer_type_from_value_;}
+
+private:
+  rcl_interfaces::msg::ParameterDescriptor impl_;
+  bool infer_type_from_value_;
+};
+
+}  // namespace rclcpp
+
+#endif  // RCLCPP__PARAMETER_DESCRIPTOR_HPP_

rclcpp/src/rclcpp/node.cpp

@@ -223,7 +223,7 @@ const rclcpp::ParameterValue &
 Node::declare_parameter(
   const std::string & name,
   const rclcpp::ParameterValue & default_value,
-  const rcl_interfaces::msg::ParameterDescriptor & parameter_descriptor,
+  const rclcpp::ParameterDescriptor & parameter_descriptor,
   bool ignore_override)
 {
   return this->node_parameters_->declare_parameter(
@@ -233,6 +233,20 @@ Node::declare_parameter(
     ignore_override);
 }
 
+const rclcpp::ParameterValue &
+Node::declare_parameter(
+  const std::string & name,
+  rclcpp::ParameterType type,
+  const rcl_interfaces::msg::ParameterDescriptor & parameter_descriptor,
+  bool ignore_override)
+{
+  return this->node_parameters_->declare_parameter(
+    name,
+    type,
+    parameter_descriptor,
+    ignore_override);
+}
+
 void
 Node::undeclare_parameter(const std::string & name)
 {