Make variable notation explicit

src/main.rs

@@ -28,19 +28,38 @@ impl Program {
         return Program{ data: op_list, pc: 0, vars: HashMap::new() };
     }
 
-    fn args_or_vars<'a>(&self, arguments: &'a str) -> String {
-        let mut deconstructed: Vec<char> = arguments.chars().collect();
+    fn args_or_vars(&self, arguments: &str) -> String {
+        let mut builder = String::from("");
+        let argument_vec: Vec<char> = arguments.chars().collect();
 
-        for (index, char) in arguments.chars().enumerate() {
-            let value = self.vars.get(&char);
+        for index in 0..argument_vec.len() {
+            let current_char = argument_vec[index];
+            let str_to_push: String;
 
-            match value {
-                Some(content) => deconstructed[index] = *content,
-                None => {}
+            if index > 0 {
+                if argument_vec[index-1] == '$' {
+                    continue;
+                }
             }
+            
+            if current_char == '$' {
+                let variable = argument_vec[index+1];
+
+                let key = self.vars.get(&variable);
+                match key {
+                    Some(value) => str_to_push = value.to_string(),
+                    None => panic!("NotFoundError: Variable {} has not been defined", variable)
+                }
+
+            } else {
+                str_to_push = current_char.to_string();
+            }
+
+
+            builder.push_str(&str_to_push);
         }
 
-        deconstructed.into_iter().collect()
+        builder
     }
 
     fn add_var(&mut self, arguments: &str) {
@@ -60,7 +79,7 @@ impl Program {
             'm' => println!("{}", eval::do_math(self.args_or_vars(arguments), '*')),
             'd' => println!("{}", eval::do_math(self.args_or_vars(arguments), '/')),
             'l' => self.add_var(arguments),
-            _ => panic!("SyntaxError at opcode {}!", self.pc)
+            _ => panic!("SyntaxError: No such opcode: {}", self.pc)
         }
     }