Add more exmaples and fix CI

examples/03_multi_output/main.cpp

@@ -1,3 +1,75 @@
+// Example 03 — Multi-Output (Fan-Out)
+//
+// A single "parse" node reads "KEY=VALUE" strings and fans out to two
+// independent downstream sinks — one for keys, one for values.
+//
+//                              +--> [print_key]
+//  [generate] --string--> [parse]
+//                              +--> [print_value]
+//
+// The parser returns std::tuple<std::string, std::string>.
+// Network::connect() routes each element of the tuple to a different node.
+
 #include <kpn/kpn.hpp>
-// TODO: implement example
-int main() { return 0; }
+#include <chrono>
+#include <iostream>
+#include <string>
+#include <thread>
+#include <tuple>
+
+// ── Node functions ────────────────────────────────────────────────────────────
+
+static int gen_index = 0;
+
+static std::string generate() {
+    static const char* pairs[] = {
+        "host=localhost",
+        "port=8080",
+        "timeout=30s",
+        "retries=3",
+        "protocol=http2",
+    };
+    std::this_thread::sleep_for(std::chrono::milliseconds(60));
+    return pairs[gen_index++ % 5];
+}
+
+// Multi-output: returns (key, value) as a tuple — KPN++ routes each element
+// to its own output port automatically.
+static std::tuple<std::string, std::string> parse(std::string kv) {
+    auto sep = kv.find('=');
+    if (sep == std::string::npos) return {kv, ""};
+    return {kv.substr(0, sep), kv.substr(sep + 1)};
+}
+
+static void print_key(std::string key) {
+    std::cout << "KEY   → " << key << '\n';
+}
+
+static void print_value(std::string value) {
+    std::cout << "VALUE → " << value << '\n';
+}
+
+// ── main ──────────────────────────────────────────────────────────────────────
+
+int main() {
+    using namespace kpn;
+
+    auto gen  = make_node<generate>(out<"kv">{},          4);
+    auto par  = make_node<parse>   (in<"kv">{},  out<"key", "value">{}, 4);
+    auto keys = make_node<print_key>  (in<"key">{},   4);
+    auto vals = make_node<print_value>(in<"value">{}, 4);
+
+    Network net;
+    net.add("gen",  gen)
+       .add("par",  par)
+       .add("keys", keys)
+       .add("vals", vals)
+       .connect("gen",  gen.template output<"kv">(),    "par",  par.template input<"kv">())
+       .connect("par",  par.template output<"key">(),   "keys", keys.template input<"key">())
+       .connect("par",  par.template output<"value">(), "vals", vals.template input<"value">())
+       .build();
+
+    net.start();
+    std::this_thread::sleep_for(std::chrono::milliseconds(600));
+    net.stop();
+}