example_ForLoop_main.cpp

A simple example which shows how to implement a for loop with state_machine_cpp

//
// Created by henri on 10/05/21.
//
 
#include <iostream>
#include "basics.h"
 
using namespace state_machine_cpp;
 
class ForLoop final : public Algorithm::Builder {
public:
 
    struct Attributes {
        int iteration = 0;
        int max_iteration;
        explicit Attributes(int max_iteration) : max_iteration(max_iteration) {}
    };
 
    static AttributeTree<Layer<ForLoop::Attributes>>* create_attributes(int max_iteration) {
        return new AttributeTree<Layer<ForLoop::Attributes>>(new Layer(new Attributes(max_iteration)));
    }
 
    static const State::Id INITIAL_STATE;
    static const State::Id LOOP_CONDITION_EVALUATION;
    static const State::Id BEGIN_OF_ITERATION;
    static const State::Id END_OF_ITERATION;
    static const State::Id FINAL_STATE;
 
    static void print_end_of_loop(Context& context) {
        std::cout << "The loop is over" << std::endl;
    }
 
    static void initialize_counter(Context& context) {
        auto& attributes = context.get<Attributes>();
        attributes.iteration = 0;
    }
 
    static bool evaluate_loop_condition(const Context& context) {
        auto& attributes = context.get<Attributes>();
        return attributes.iteration < attributes.max_iteration;
    }
 
    static void apply_loop_effect(Context& context) {
        std::cout << context.get<Attributes>().iteration << std::endl;
    }
 
    static void increment_counter(Context& context) {
        context.get<Attributes>().iteration++;
    }
 
    void build(States &states, Transitions &transitions, Layers &layers) override {
 
        states.create(INITIAL_STATE);
        states.create(LOOP_CONDITION_EVALUATION);
        states.create(BEGIN_OF_ITERATION);
        states.create(END_OF_ITERATION);
        states.create(FINAL_STATE);
 
        transitions.create(INITIAL_STATE, LOOP_CONDITION_EVALUATION, initialize_counter, "$iteration = 0");
        transitions.create_if(LOOP_CONDITION_EVALUATION, BEGIN_OF_ITERATION, FINAL_STATE,evaluate_loop_condition, "$iteration < $max_iteration");
        transitions.create(BEGIN_OF_ITERATION, END_OF_ITERATION, apply_loop_effect, "show $iteration");
        transitions.create(END_OF_ITERATION, LOOP_CONDITION_EVALUATION, increment_counter, "$iteration++");
        transitions.create(FINAL_STATE, FINAL_STATE, print_end_of_loop);
 
    }
 
};
 
const State::Id ForLoop::INITIAL_STATE = State::Id("ForLoop::INITIAL_STATE");
const State::Id ForLoop::LOOP_CONDITION_EVALUATION = State::Id("ForLoop::LOOP_CONDITION_EVALUATION");
const State::Id ForLoop::BEGIN_OF_ITERATION = State::Id("ForLoop::BEGIN_OF_ITERATION");
const State::Id ForLoop::END_OF_ITERATION = State::Id("ForLoop::END_OF_ITERATION");
const State::Id ForLoop::FINAL_STATE = State::Id("ForLoop::FINAL_STATE");
 
#ifndef STATE_MACHINE_CPP_EXAMPLE_FORLOOP_H
 
int main() {
 
    Algorithm::Instance algorithm;
    Algorithm::build<ForLoop>(algorithm);
    Algorithm::plot(algorithm, "my_algorithm", true);
    Algorithm::sanity_check(algorithm);
 
    //auto context_tree = ForLoop::create_attributes(10);
    //Context context(context_tree);
    auto context = Context::create<ForLoop>(10);
 
    Algorithm::run(algorithm, context);
 
    return 0;
}
 
#endif // STATE_MACHINE_CPP_EXAMPLE_FORLOOP_H