Now returns an error when not all program args are passed via command-line

There was a lot of stuff added here. The most important addition is
how Pirate now returns a MissingArgument kinded error if a required
program argument isn't passed to the program.

README.md

@@ -13,9 +13,10 @@ Ever.
 
 In all seriousness, `getopts` is a fantastic library that gives the developers all of the tools
 necessary to create and interface with command-line arguments. However, with all that power comes
-complexity. `getopts`, while straight forward to use, is verbose. The developer has to make repeated
-method calls to add different command-line options. And while the only victim here is the
-developer's wrists due to carpal tunnel, I felt that there was a better way to do things.
+complexity. `getopts` -- while straight forward to use -- is verbose. The developer has to call
+different functions repeatedly in order to add different command-line options to their programs. And
+while the only victim here is the developer's wrists due to carpal tunnel, I felt that there was a
+better way to do things.
 
 Enter Pirate (which should totally usurp `getopts` for the award of Most Originally Named Project Ever).
 
@@ -32,7 +33,7 @@ pirate = "0.1.0"
 and this to your crate root:
 
 ```rust
-extern crate getopts;
+extern crate pirate;
 ```
 
 Usage
@@ -145,7 +146,7 @@ To Do
 - [ ] Create a helper function for generating `--help` output, rather than having the user create it
 manually.
   - [ ] Also create helper functions for defining the description section of the `--help` output.
-- [ ] Refactor the `ErrorKind` enum into a struct that is able to represent more complex data (such
+- [x] Refactor the `ErrorKind` enum into a struct that is able to represent more complex data (such
   giving the value of the invalid argument passed to the program).
 
 License

src/errors.rs

@@ -28,34 +28,36 @@ pub struct Error {
 impl Error {
     pub fn new(kind: ErrorKind, offender: String) -> Error {
         Error {
-            kind: kind,
-            offender: offender,
+            kind: kind.clone(),
+            offender: offender.clone(),
+            desc: format!("{} {}", kind.description(), offender.clone()),
         }
     }
 }
 
 impl error::Error for Error {
     fn description(&self) -> &str {
-        &format!("{} {}", self.kind.description(), self.offender);
+        &self.desc
     }
 }
 
 impl Display for Error {
     fn fmt(&self, f: &mut Formatter) -> Result {
-        write!(f, "{}", self.description())
+        write!(f, "{}", self.desc)
     }
 }
 
+#[derive(Clone, Debug)]
 pub enum ErrorKind {
     InvalidOption,
     MissingArgument,
 }
 
 impl ErrorKind {
-    fn description(&self) -> &str {
+    fn description(&self) -> String {
         match *self {
-            ErrorKind::InvalidOption => "An invalid option was passed to the program:",
-            ErrorKind::MissingArgument => "A required argument is missing:",
+            ErrorKind::InvalidOption => String::from("An invalid option was passed to the program:"),
+            ErrorKind::MissingArgument => String::from("A required argument is missing:"),
         }
     }
 }

src/lib.rs

@@ -25,7 +25,7 @@ pub use errors::{Error, ErrorKind};
 pub use matches::Matches;
 use opts::Opts;
 
-pub fn parse(mut args: Args, options: &[&'static str]) -> Result<Matches, ErrorKind> {
+pub fn parse(mut args: Args, options: &[&'static str]) -> Result<Matches, Error> {
     let mut matches: Matches = Matches::new();
 
     let mut opts: Opts = opts(options); // Jesus, this is redundant...
@@ -73,7 +73,10 @@ pub fn parse(mut args: Args, options: &[&'static str]) -> Result<Matches, ErrorK
         next_arg = args.next();
     }
 
-    Ok(matches)
+    match opts.arg_len() {
+        0 => Ok(matches),
+        _ => Err(Error::new(ErrorKind::MissingArgument, opts.get_arg().unwrap())),
+    }
 }
 
 fn opts(opts: &[&'static str]) -> Opts {

src/opts.rs

@@ -50,4 +50,8 @@ impl Opts {
     pub fn get_arg(&mut self) -> Option<String> {
         self.args.pop_front()
     }
+
+    pub fn arg_len(&self) -> usize {
+        self.args.len()
+    }
 }

tests/main.rs

@@ -23,6 +23,7 @@ fn main() {
     }
 
     let input = matches.get("input").unwrap().parse::<i32>().unwrap();
+
     let num = match matches.get("n") {
         Some(n) => n.parse::<i32>().unwrap(),
         None => 1