template_lambda.h

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#pragma once
 
#include "esphome/core/optional.h"
 
namespace esphome {
 
template<typename T, typename... Args> class TemplateLambda {
 public:
  TemplateLambda() : f_(nullptr) {}
 
  void set(optional<T> (*f)(Args...)) { this->f_ = f; }
 
  bool has_value() const { return this->f_ != nullptr; }
 
  optional<T> operator()(Args &&...args) {
    if (this->f_ == nullptr)
      return nullopt;
    return this->f_(std::forward<Args>(args)...);
  }
 
  optional<T> call(Args &&...args) { return (*this)(std::forward<Args>(args)...); }
 
 protected:
  optional<T> (*f_)(Args...);  // Function pointer (4 bytes on ESP32)
};
 
}  // namespace esphome