args checking

src/main.rs

@@ -44,6 +44,9 @@ fn main() {
     if res.is_ok() {
         pattern = res.unwrap();
     }
+    else {
+        println!("ret err {:?}", res.unwrap_err());
+    }
 
     //pattern management
     loop {

src/util/pattern.rs

@@ -54,19 +54,43 @@ impl Pattern for Value {
         }
     }
     fn parse(args: Vec<String>) -> Result<Self, ParseError> {
-        let param1 = args[1].parse::<u8>();
-        let param2 = args[2].parse::<u8>();
-        let param3 = args[3].parse::<u8>();
-        if param1.is_ok() && param2.is_ok() && param3.is_ok() {
+        let param1 = 
+        if args.len() >= 1 {
+            match args[1].parse::<u8>() {
+                Ok(i) => Some(i),
+                Err(_) => None
+            }
+        } else {
+            None
+        }
+        let param2 = 
+        if args.len() >= 2 {
+            match args[2].parse::<u8>() {
+                Ok(i) => Some(i),
+                Err(_) => None
+            }
+        } else {
+            None
+        }
+        let param3 = 
+        if args.len() >= 3 {
+            match args[3].parse::<u8>() {
+                Ok(i) => Some(i),
+                Err(_) => None
+            }
+        } else {
+            None
+        }
+        if param1.is_some() && param2.is_some() && param3.is_some() {
             Ok(Value{
-                r: Some(param1.unwrap()),
-                g: Some(param2.unwrap()),
-                b: Some(param3.unwrap())
+                r: param1,
+                g: param2,
+                b: param3
             })
         }
-        else {
+        else if args.len() >= 2 {
             match param2 {
-                Ok(i) => match args[1].as_str() {
+                Some(i) => match args[1].as_str() {
                     "r" => {
                         Ok(Value {
                             r: Some(i),
@@ -88,11 +112,14 @@ impl Pattern for Value {
                             b: Some(i)
                         })
                     }
-                    _ => Err("unreachable".into())
+                    _ => Err("no rgb".into())
                 },
-                Err(e) => Err(Box::new(e)) 
+                None => Err("no param2".into()) 
             }
         }
+        else {
+            Err("incorrect number of arguments".into())
+        }
     }
 }