skeleton of merge functionality

src/bin/bitsy-merge.rs

@@ -0,0 +1,26 @@
+extern crate bitsy_parser;
+use bitsy_parser::game::Game;
+use std::{env, fs};
+
+fn main() {
+    let game_a = env::args()
+        .nth(1)
+        .expect("No main game specified. Usage: `bitsy-merge main.bitsy additional.bitsy output.bitsy`");
+
+    // todo allow numerous additional games
+    let game_b = env::args()
+        .nth(2)
+        .expect("No additional game specified. Usage: `bitsy-merge main.bitsy additional.bitsy output.bitsy`");
+
+    let outfile = env::args()
+        .nth(3)
+        .expect("No output file specified. Usage: `bitsy-merge main.bitsy additional.bitsy output.bitsy`");
+
+    let mut game_a = Game::from(fs::read_to_string(game_a).unwrap()).unwrap();
+    let     game_b = Game::from(fs::read_to_string(game_b).unwrap()).unwrap();
+
+    game_a.merge(game_b);
+
+    fs::write(outfile, game_a.to_string())
+        .expect("Failed to write output file");
+}