add docs, improve readme

README.md

@@ -3,3 +3,10 @@
 [![Coverage Status](https://coveralls.io/repos/pyfisch/rust-charsets/badge.svg)](https://coveralls.io/r/pyfisch/rust-charsets)
 [![MIT licensed](https://img.shields.io/badge/license-MIT-blue.svg)](./LICENSE)
 [![crates.io](http://meritbadge.herokuapp.com/rust-charsets)](https://crates.io/crates/rust-charsets)
+
+The crate provides an enum representing all charset names used in Media Types
+and HTTP header values. The list can be found at [the IANA Character Sets
+registry](http://www.iana.org/assignments/character-sets/character-sets.xhtml).
+
+Charset names can be parsed from string, formatted to string and compared.
+Unregistered charsets are represented useing an `Unregistered` variant.

src/lib.rs

@@ -1,12 +1,27 @@
+#![deny(missing_docs)]
+#![cfg_attr(test, deny(warnings))]
+
+//! The crate provides an enum representing all charset names used in Media Types
+//! and HTTP header values. The list can be found at [the IANA Character Sets
+//! registry](http://www.iana.org/assignments/character-sets/character-sets.xhtml).
+//!
+//! Charset names can be parsed from string, formatted to string and compared.
+//! Charset names can be parsed from string, formatted to string and compared.
+//! Unregistered charsets are represented using an `Unregistered` variant.
+
 use std::fmt::{self, Display};
 use std::str::FromStr;
 use std::ascii::AsciiExt;
 use std::error::Error as ErrorTrait;
 
-use self::Charset::*;
+pub use self::Charset::*;
 
+/// An error type used for this crate.
+///
+/// It may be extended in the future to give more information.
 #[derive(Debug, Eq, PartialEq)]
 pub enum Error {
+    /// Parsing as as charset failed.
     Invalid
 }
 
@@ -171,6 +186,10 @@ impl PartialEq for Charset {
     }
 }
 
+#[cfg(test)]
+mod tests {
+    use super::*;
+
     #[test]
     fn test_parse() {
         assert_eq!(UsAscii,"us-ascii".parse().unwrap());
@@ -190,3 +209,4 @@ fn test_display() {
     fn test_cmp() {
         assert_eq!(Unregistered("foobar".to_owned()), Unregistered("FOOBAR".to_owned()));
     }
+}