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// 2020/08/28 - Created by netcan: https://github.com/netcan
// Task DSL demo
// The example creates the following cyclic graph:
//
// A
// |
// v
// B<---|
// | |
// v |
// C----|
// |
// v
// D
//
// - A is a task that initializes a counter to zero
// - B is a task that increments the counter
// - C is a condition task that loops around B until the counter
// reaches a breaking number
// - D is a task that wraps up the result
#include <taskflow/taskflow.hpp>
#include <taskflow/dsl.hpp>
int main() {
tf::Executor executor;
tf::Taskflow taskflow("Conditional Tasking Demo");
int counter; // owner
// use context to pass args
// context must copyable
struct Context {
int &rcounter; // use counter(borrow)
} context{counter};
make_task((A, Context), {
std::cout << "initializes the counter to zero\n";
rcounter = 0;
});
make_task((B, Context), {
std::cout << "loops to increment the counter\n";
rcounter++;
});
make_task((C, Context), {
std::cout << "counter is " << rcounter << " -> ";
if (rcounter != 5) {
std::cout << "loops again (goes to B)\n";
return 0;
}
std::cout << "breaks the loop (goes to D)\n";
return 1;
});
make_task((D, Context), {
std::cout << "done with counter equal to " << rcounter << '\n';
});
auto tasks = build_taskflow(
task(A)
-> task(B)
-> task(C),
task(C)
-> fork_tasks(B, D)
)(taskflow, context);
tasks.get_task<A>().name("A");
tasks.get_task<B>().name("B");
tasks.get_task<C>().name("C");
tasks.get_task<D>().name("D");
// visualizes the taskflow
taskflow.dump(std::cout);
// executes the taskflow
executor.run(taskflow).wait();
assert(counter == 5);
return 0;
}
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