cep27

CEP 27 - Toolkit Capabilities Injection into an Archetype

CEP:	27
Title:	Agent Toolkit Capabilities
Last-Modified:	2019-10-28
Author:	Baptiste Mouginot <[email protected]>
Status:	Active
Type:	Standards Track
Created:	Baptiste Mouginot

Abstract

The |Cyclus| toolkit is designed to easily implement specific capabilities in newly developed archetypes, such as a trading policy, commodity producers, etc. To add characteristics to archetypes such as Position or Metadata, the actual implementation method is very verbose. It relies on adding the new specification in the archetype header, assigning it and use it in the cpp file. The developers have to manually ensure the consistency in variable naming and implementation across multiple archetypes/files. This CEP explains introduces the concept of snippets to simplify and maintain consistency in the implementation and the usage, across multiple archetypes.

Toolkit Implementation

Each |Cyclus| toolkit component will contain 3 different files: - 2 for the definition of the feature C++ class (cpp and header) that allows

the use of the capabilities, and optionally to register its values in the output database,

• a snippet definition file used to simplify the implementation and ensure consistency accross its integration in the different archetypes.

The snippet definition file will be included in the private section of the archetype header as: #include toolkit/my_feature_snippet.cycpp.h. (The use of the cycpp.h has been chosen to allow syntax highlighting and inform developers that this is not a standard C++ header.)

The snippet file, will contain the declaration of all the variables required to use the capabilities class:

• the definition of the capability class as a member variable.
• initialization of the added variables.
• (optional) if the capability requires/allows variable input from users, standard |Cyclus| member variable declaration with variable #pragma is required. In addition, to the standard variable declaration and the #pragma the method also require a std::vector<int> cycpp_shape_myvariable to be declared for each of the decorated variable that are in the toolkit/my_feature_snippet.cycpp.h file. (cycpp preprocessor is not able at the time to add them automatically for included files.)

The main purpose of this include method would be to ensure consistency across archetypes using the same toolkit capability requiring user input, avoiding 1 set of input syntax per archetypes for the same capability.

If the toolkit features needs the capabilities to write in the output database a RecordSnippet(Agent* agent) method will be implemented in the toolkit class to avoid multiplication of implementation in the each archetype using the feature.

Archetypes Integration

When the capability is integrated in an Archetype the following implementations have to be done:

1. Include toolkit class header in in the class header: #include 'toolkit/my_feature.h'.
2. Include the snippet in the class header core: #include toolkit/my_feature_snippet.cycpp,h.
3. (optional) In the Archetype::EnterNotify(), initialise the toolkit class member variables with variables.
4. (optional) If required, call the RecordSnippet() method when necessary during the Archetype operation.

Class member vs Inheritance

With inheritance of the capability class, one will need to also modify the archetype class declaration in addition to simply including the snippet at the right place. This may also lead to confusion, as one can believe that the user input value for variable are passed in the constructor of the class and might lead the develop to skip the assignation of the value in the inherited class in the EnterNotify...

Otherwise behavior would be very similar.

Example:

Without Inheritance:

toolkit/my_feature_snippet.cycpp.h: .. highlight:: c

cyclus::toolkit::Position coordinates(0,0);

#pragma cyclus var {

"default": 0.0, "uilabel": "Geographical latitude in degrees as a double", "doc": "Latitude of the agent's geographical position. The value should "

"be expressed in degrees as a double." }

double latitude = 0; // required for compilation but not added by the cycpp preprocessor... std::vector<int> cycpp_shape_latitude;

#pragma cyclus var {

"default": 0.0, "uilabel": "Geographical longitude in degrees as a double", "doc": "Longitude of the agent's geographical position. The value should" "be expressed in degrees as a double." }

double longitude = 0; // required for compilation but not added by the cycpp preprocessor... std::vector<int> cycpp_shape_longitude;

my_archetype_example.h: .. highlight:: c

#include 'toolkit/Position.h'

class fun_archetype : public cyclus::facility{

public: [...] private: [...] #include "toolkit/my_feature_snippet.cycpp.h"

}

my_archetype_example.cpp: .. highlight:: c

void fun_archetype::EnterNotify() {

coordinates.set_position(latitude, longitude); coordinates.RecordPosition(this); [...] }

With Inheritance:

toolkit/my_feature_snippet.cycpp.h: .. highlight:: c

#pragma cyclus var {

"default": 0.0, "uilabel": "Geographical latitude in degrees as a double", "doc": "Latitude of the agent's geographical position. The value should "

"be expressed in degrees as a double." }

double latitude = 0; // required for compilation but not added by the cycpp preprocessor... std::vector<int> cycpp_shape_latitude;

#pragma cyclus var {

"default": 0.0, "uilabel": "Geographical longitude in degrees as a double", "doc": "Longitude of the agent's geographical position. The value should" "be expressed in degrees as a double." }

double longitude = 0; // required for compilation but not added by the cycpp preprocessor... std::vector<int> cycpp_shape_longitude;

my_archetype_example.h: .. highlight:: c

#include 'toolkit/Position.h'

class fun_archetype : public cyclus::facility, public Position {

public: [...] private: [...] #include "toolkit/my_feature_snippet.cycpp.h"

}

my_archetype_example.cpp: .. highlight:: c

void fun_archetype::EnterNotify() {

this.set_position(latitude, longitude); this.RecordPosition(this); [...] }