Add support for multi-character vars

src/main.rs

@@ -9,7 +9,7 @@ mod eval;
 struct Program {
     data: Vec<String>,
     pc: usize,
-    vars: HashMap<char, char>
+    vars: HashMap<char, String>
 }
 
 impl Program {
@@ -64,8 +64,10 @@ impl Program {
 
     fn add_var(&mut self, arguments: &str) {
         let argument_vec: Vec<char> = arguments.chars().collect();
+        let name = argument_vec[0];
+        let value = argument_vec[1..].into_iter().collect::<String>();
 
-        self.vars.insert(argument_vec[0], argument_vec[1]);
+        self.vars.insert(name, value);
     }
 
     fn parse(&mut self, instruction: &String) {