Updated readme

README.md

@@ -1,2 +1,81 @@
 # clap-rs
 Command Line Argument Parser written in Rust
+
+ A simply library for parsing command line arguments when writing 
+ command line and console applications.
+
+
+ You can use `clap` to lay out a list of possible valid command line arguments and let `clap` parse the string given by the user at runtime.
+ When using `clap` you define a set of parameters and rules for your arguments and at runtime `clap` will determine their validity.
+ Also, `clap` provides the traditional version and help switches 'for free' by parsing the list of possible valid arguments lazily at runtime.
+ i.e. only when it's been determined that the user wants or needs to see the help and version information.
+ 
+ After defining a list of possible valid arguments you get a list of matches that the user supplied at runtime. You can then use this list to
+ determine the functioning of your program.
+
+ Example:
+ 
+ ```rust
+ extern crate clap;
+ use clap::{Arg, App};
+
+ // ...
+ 
+ let matches = App::new("MyApp")
+						.version("1.0")
+						.author("Kevin K. <kbknapp@gmail.com>")
+						.about("Does awesome things")
+						.arg(Arg::new("config")
+									.short("c")
+									.long("config")
+									.help("Sets a custom config file")
+									.takes_value(true))
+						.arg(Arg::new("output")
+									.help("Sets an optional output file")
+									.index(1))
+						.arg(Arg::new("debug")
+									.short("d")
+ 								.multiple(true)
+									.help("Turn debugging information on"))
+						.get_matches();
+
+	if let Some(o) = matches.value_of("output") {
+		println!("Value for output: {}", o);
+	}
+ 
+	if let Some(c) = matches.value_of("config") {
+		println!("Value for config: {}", c);
+	}
+
+ match matches.occurrences_of("debug") {
+ 	0 => println!("Debug mode is off"),
+		1 => println!("Debug mode is kind of on"),
+		2 => println!("Debug mode is on"),
+		3 | _ => println!("Don't be crazy"),
+ }
+ 
+ // more porgram logic goes here...
+ ```
+
+ If you were to compile the above program and run it with the flag `--help` or `-h` the following output woud be presented
+
+ ```sh
+ $ myprog --help
+ MyApp 1.0
+ Kevin K. <kbknapp@gmail.com>
+ Does awesome things
+ 
+ USAGE:
+ 	MyApp [FLAGS] [OPTIONS] [POSITIONAL]
+ 
+ FLAGS:
+ -d   			Turn debugging information on
+ -h,--help		Prints this message
+ -v,--version	Prints version information
+ 
+ OPTIONS:
+ -c,--config <config>		Sets a custom config file
+
+ POSITIONAL ARGUMENTS:
+ output			Sets an optional output file
+ ```