More explicit use of "Optional".

src/main.cpp

@@ -1,11 +1,9 @@
 #include <algorithm>
 #include <iostream>
-#include <memory>
 #include <glog/logging.h>
 
 #include "Options.hpp"
 #include "Simulator.hpp"
-#include "PNGDumper.hpp"
 
 using namespace std;
 using namespace fmri;
@@ -14,15 +12,8 @@ int main(int argc, char *const argv[]) {
     google::InitGoogleLogging(argv[0]);
 
     Options options = Options::parse(argc, argv);
-    vector<string> labels;
-    if (!options.labels().empty()) {
-        labels = read_vector<string>(options.labels());
-    }
-
-    unique_ptr<PNGDumper> pngDumper;
-    if (!options.imageDump().empty()) {
-        pngDumper.reset(new PNGDumper(options.imageDump()));
-    }
+    auto labels = options.labels();
+    auto dumper = options.imageDumper();
 
     Simulator simulator(options.model(), options.weights(), options.means());
 
@@ -31,9 +22,9 @@ int main(int argc, char *const argv[]) {
 		LOG(INFO) << "Result for " << image << ":" << endl;
 
 		const auto& resultRow = res[res.size() - 1];
-		if (!labels.empty()) {
+		if (labels) {
 			vector<DType> weights(resultRow.data(), resultRow.data() + resultRow.numEntries());
-			auto scores = combine(weights, labels);
+			auto scores = combine(weights, *labels);
 			sort(scores.begin(), scores.end(), greater<>());
 			for (unsigned int i = 0; i < scores.size() && i < 5; ++i) {
 				LOG(INFO) << scores[i].first << " " << scores[i].second << endl;
@@ -42,9 +33,11 @@ int main(int argc, char *const argv[]) {
 			LOG(INFO) << "Best result: " << *(resultRow.data(), resultRow.data() + resultRow.numEntries()) << endl;
 		}
 
-		for (auto& layer : res) {
-			pngDumper->dump(layer);
-		}
+        if (dumper) {
+            for (const auto& layer : res) {
+                dumper->dump(layer);
+            }
+        }
 	}
 
     google::ShutdownGoogleLogging();