diff --git a/builder.cpp b/builder.cpp
index e59cbe2..89c85b4 100644
--- a/builder.cpp
+++ b/builder.cpp
@@ -1,12 +1,6 @@
 #include "builder.hpp"
 #include "dbc.hpp"
-#include "watcher.hpp"
-#include "game_engine.hpp"
 #include <chrono>                     // for milliseconds
-#include <efsw/efsw.hpp>
-#include <fmt/chrono.h>
-#include <fmt/color.h>
-#include <fmt/core.h>
 #include <fmt/core.h>
 #include <fstream>
 #include <git2.h>
@@ -82,122 +76,116 @@ MatchResult Builder::parse_line(const string &line) {
   }
 }
 
-enum BuildState {
-  WAITING, BUILDING, DONE, STARTING, READING
-};
+void Builder::run() {
+  int rc = gui.main_loop(game, [&] {
+      event(GO);
+      return 0;
+  });
 
+  if(rc != 0) println("ERROR IN GUI");
 
-void Builder::run() {
-  git_repository* repo = nullptr;
-
-  try {
-    gui.output(format("Using build command: {}", build_cmd));
-    efsw::FileWatcher* fileWatcher = new efsw::FileWatcher();
-    dbc::check(fileWatcher != nullptr, "Failed to create filewatcher.");
-
-    git_libgit2_init();
-
-    int err = git_repository_open(&repo, git_path.c_str());
-    dbc::check(err == 0, git_error_last()->message);
-
-    UpdateListener* listener = new UpdateListener(repo);
-    dbc::check(listener != nullptr, "Failed to create listener.");
-
-    gui.output(format("Watching directory {} for changes...", git_path));
-    efsw::WatchID wid = fileWatcher->addWatch(git_path, listener, true);
-
-    FILE *build_out = NULL;
-    bool build_done = false;
-    string line = "";
-    BuildState state = WAITING;
-    std::future<FILE *> build_fut;
-
-    fileWatcher->watch();
-
-    int rc = gui.main_loop(game, [&] {
-      switch(state) {
-      case WAITING:
-        if(listener->changes) {
-          game.start_round();
-          gui.building();
-          gui.output(format("CHANGES! Running build {}", build_cmd));
-          build_fut = std::async([&]() {
-              return start_command(build_cmd);
-          });
-          state = STARTING;
-        }
-      break;
-
-      case STARTING: {
-          println(">>> STARTING");
-          std::future_status status = build_fut.wait_for(0ms);
-
-          if(status == std::future_status::ready) {
-            build_out = build_fut.get();
-            state = READING;
-          } else {
-            state = STARTING;
-          }
-        }
-        break;
-
-      case READING: {
-          line = read_line(build_out, build_done);
-          state = BUILDING;
-          }
-      break;
-      case BUILDING: {
-          println(">>> BUILDING");
-          // check if there's output
-          if(build_done) {
-            bool good = end_build(build_out, gui, build_cmd);
-
-            if(good) {
-              gui.build_works();
-            } else {
-              // BUG: make it not play two sounds
-              gui.build_failed(true, build_cmd);
-            }
-
-            build_out = NULL;
-            state = DONE;
-          } else {
-            auto m = parse_line(line);
-
-            if(m.match) {
-              gui.output(format("HIT WITH {} @ {}:{}:{} {}", m.type, m.file_name, m.lnumber, m.col, m.message));
-              game.hit(m.type);
-            }
-            state = READING;
-          }
-       }
-      break;
-
-      case DONE: {
-        game.end_round();
-
-        if(game.is_dead()) {
-          gui.you_died();
-          game.reset();
-        }
-
-        listener->reset_state();
-        gui.output("^^^^^^^^^^^ END ^^^^^^^^^^^");
-        state = WAITING;
-       }
-      break;
-      }
+  event(QUIT);
+}
 
-      return 0;
+void Builder::building(BuildEvent ev) {
+  println(">>> BUILDING");
+  // check if there's output
+  if(build_done) {
+    bool good = end_build(build_out, gui, build_cmd);
+
+    if(good) {
+      gui.build_works();
+    } else {
+      // BUG: make it not play two sounds
+      gui.build_failed(true, build_cmd);
+    }
+
+    build_out = NULL;
+    state(DONE);
+  } else {
+    auto m = parse_line(line);
+
+    if(m.match) {
+      gui.output(format("HIT WITH {} @ {}:{}:{} {}", m.type, m.file_name, m.lnumber, m.col, m.message));
+      game.hit(m.type);
+    }
+    state(READING);
+  }
+}
+
+void Builder::start(BuildEvent ev) {
+  gui.output(format("Using build command: {}", build_cmd));
+  fileWatcher = new efsw::FileWatcher();
+  dbc::check(fileWatcher != nullptr, "Failed to create filewatcher.");
+
+  git_libgit2_init();
+
+  int err = git_repository_open(&repo, git_path.c_str());
+  dbc::check(err == 0, git_error_last()->message);
+
+  listener = new UpdateListener(repo);
+  dbc::check(listener != nullptr, "Failed to create listener.");
+
+  gui.output(format("Watching directory {} for changes...", git_path));
+  wid = fileWatcher->addWatch(git_path, listener, true);
+  fileWatcher->watch();
+
+  state(WAITING);
+}
+
+void Builder::waiting(BuildEvent ev) {
+  if(listener->changes) {
+    game.start_round();
+    gui.building();
+    gui.output(format("CHANGES! Running build {}", build_cmd));
+    build_fut = std::async([&]() {
+        return start_command(build_cmd);
     });
+    state(STARTING);
+  }
+}
 
-    dbc::check(rc == 0, "Invalid return from main_loop.");
+void Builder::starting(BuildEvent ev) {
+  std::future_status status = build_fut.wait_for(0ms);
+
+  if(status == std::future_status::ready) {
+    build_out = build_fut.get();
+    state(READING);
+  } else {
+    state(STARTING);
+  }
+}
+
+void Builder::reading(BuildEvent ev) {
+  line = read_line(build_out, build_done);
+  state(BUILDING);
+}
 
+void Builder::done(BuildEvent ev) {
+  game.end_round();
+
+  if(game.is_dead()) {
+    gui.you_died();
+    game.reset();
+  }
+
+  listener->reset_state();
+  gui.output("^^^^^^^^^^^ END ^^^^^^^^^^^");
+  state(WAITING);
+}
+
+void Builder::exit(BuildEvent ev) {
+  if(ev == QUIT) {
     fileWatcher->removeWatch(wid);
     git_libgit2_shutdown();
-  } catch(dbc::Error &err) {
+    state(EXIT);
+  }
+}
+
+void Builder::error(BuildEvent ev) {
+  // how to avoid doing this more than once?
+  if(ev == CRASH) {
     if(repo != nullptr) git_repository_free(repo);
     git_libgit2_shutdown();
-    throw err;
   }
 }
diff --git a/builder.hpp b/builder.hpp
index 57a140c..16e370e 100644
--- a/builder.hpp
+++ b/builder.hpp
@@ -2,6 +2,11 @@
 #include "gui.hpp"
 #include "game_engine.hpp"
 #include <stdio.h>
+#include "fsm.hpp"
+#include <efsw/efsw.hpp>
+#include <future>
+#include <stdio.h>
+#include "watcher.hpp"
 
 using std::string;
 
@@ -14,11 +19,28 @@ struct MatchResult {
   string message = "";
 };
 
-class Builder {
+enum BuildState {
+  START, WAITING, BUILDING, DONE, STARTING, READING,
+  EXIT, ERROR
+};
+
+enum BuildEvent {
+  GO, QUIT, CRASH
+};
+
+class Builder : DeadSimpleFSM<BuildState, BuildEvent> {
   GUI gui;
   GameEngine game;
   string git_path = "NOT SET";
   string build_cmd = "NOT SET";
+  efsw::FileWatcher* fileWatcher = NULL;
+  UpdateListener* listener = NULL;
+  efsw::WatchID wid;
+  FILE *build_out = NULL;
+  bool build_done = false;
+  string line = "";
+  std::future<FILE *> build_fut;
+  git_repository* repo = nullptr;
 
   public:
 
@@ -27,4 +49,34 @@ class Builder {
   MatchResult parse_line(const string &line);
 
   void run();
+
+  void event(BuildEvent ev) override {
+    try {
+      if(ev == QUIT) {
+        exit(ev);
+      }
+
+      switch(_state) {
+        FSM_STATE(BUILDING, building, ev);
+        FSM_STATE(START, start, ev);
+        FSM_STATE(WAITING, waiting, ev);
+        FSM_STATE(DONE, done, ev);
+        FSM_STATE(STARTING, starting, ev);
+        FSM_STATE(READING, reading, ev);
+        FSM_STATE(EXIT, exit, ev);
+        FSM_STATE(ERROR, exit, ev);
+      }
+    } catch(...) {
+      error(ev);
+    }
+  }
+
+  void building(BuildEvent ev);
+  void start(BuildEvent ev);
+  void waiting(BuildEvent ev);
+  void done(BuildEvent ev);
+  void starting(BuildEvent ev);
+  void reading(BuildEvent ev);
+  void error(BuildEvent ev);
+  void exit(BuildEvent ev);
 };
diff --git a/fsm.hpp b/fsm.hpp
index 79117f3..fc2b505 100644
--- a/fsm.hpp
+++ b/fsm.hpp
@@ -1,5 +1,10 @@
 #pragma once
 
+#include <fmt/core.h>
+
+#define FSM_EV(S, F) case S: F(); break
+#define FSM_STATE(S, F, E) case S: fmt::println(">>> " #S ":" #F ":{}", int(E)); F(E); break
+
 template<typename S, typename E>
 class DeadSimpleFSM {
 protected:
@@ -11,6 +16,8 @@ public:
   void state(S next_state) {
     _state = next_state;
   }
-};
 
-#define FSM_T(S, F) case S: F(); break
+  bool in_state(S state) {
+    return _state == state;
+  }
+};
diff --git a/fsmtest.cpp b/fsmtest.cpp
index c18c033..d1a67d0 100644
--- a/fsmtest.cpp
+++ b/fsmtest.cpp
@@ -14,24 +14,24 @@ enum MyEvent {
 class MyFSM : DeadSimpleFSM<MyState, MyEvent> {
 public:
   void event(MyEvent ev) override {
-    switch(ev) {
-      FSM_T(STARTED, start);
-      FSM_T(PUSH, push);
-      FSM_T(QUIT, quit);
+    switch(_state) {
+      FSM_STATE(START, start, ev);
+      FSM_STATE(RUNNING, push, ev);
+      FSM_STATE(END, quit, ev);
     }
   }
 
-  void start() {
+  void start(MyEvent ev) {
     println("<<< START");
     state(RUNNING);
   }
 
-  void push() {
+  void push(MyEvent ev) {
     println("<<< RUN");
     state(RUNNING);
   }
 
-  void quit() {
+  void quit(MyEvent ev) {
     println("<<< STOP");
     state(END);
   }