Improve mnemonic formatting

src/main.rs

@@ -1,10 +1,31 @@
 use std::io::{self, Read};
 
 fn print_mnemonic(mnemonic: &str, bytes: &[u8]) {
+    let split_mnemonic: Vec<&str> = mnemonic.split(" ").collect();
+
+    let mut argument = "";
+
+    let mnemonic = split_mnemonic[0];
+    if split_mnemonic.len() == 2 {
+        argument = split_mnemonic[1];
+    }
+
     match bytes.len() {
-        1 => println!("{:02x}         {}", bytes[0], mnemonic),
-        2 => println!("{:02x} {:02x}      {:5} #0x{:02x}", bytes[0], bytes[1], mnemonic, bytes[1]),
-        3 => println!("{:02x} {:02x} {:02x}   {:5} ${:02x}{:02x}", bytes[0], bytes[1], bytes[2], mnemonic, bytes[2], bytes[1]),
+        1 => println!("{opcode:02x}         {mnemonic:6} {arg}",
+                      opcode = bytes[0],
+                      mnemonic = mnemonic,
+                      arg = argument),
+        2 => println!("{opcode:02x} {byte:02x}      {mnemonic:6} {arg}#0x{byte:02x}",
+                      opcode = bytes[0],
+                      byte = bytes[1],
+                      mnemonic = mnemonic,
+                      arg = argument),
+        3 => println!("{opcode:02x} {low_byte:02x} {high_byte:02x}   {mnemonic:6} {arg}${high_byte:02x}{low_byte:02x}",
+                      opcode = bytes[0],
+                      low_byte = bytes[1],
+                      high_byte = bytes[2],
+                      mnemonic = mnemonic,
+                      arg = argument),
 
         _ => {},
     }