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    #[allow(dead_code)]
    mod settings;
    #[macro_use]
    mod macros;
    mod parser;
    mod meta;
    mod help;

    pub use self::settings::AppSettings;

    use std::env;
    use std::io::{self, BufRead, BufWriter, Write};
    use std::path::Path;
    use std::process;
    use std::ffi::OsString;
    use std::borrow::Borrow;
    use std::result::Result as StdResult;
    use std::rc::Rc;
    use std::fmt;

    #[cfg(feature = "yaml")]
    use yaml_rust::Yaml;
    use vec_map::VecMap;

    use args::{Arg, ArgSettings, AnyArg, ArgGroup, ArgMatches, ArgMatcher};
    use app::parser::Parser;
    use app::help::Help;
    use errors::Error;
    use errors::Result as ClapResult;

    /// Used to create a representation of a command line program and all possible command line
    /// arguments. Application settings are set using the "builder pattern" with the
    /// `.get_matches()` family of methods being the terminal methods that starts the runtime-parsing
    /// process. These methods then return information about the user supplied arguments (or lack there
    /// of).
    ///
    /// **NOTE:** There aren't any mandatory "options" that one must set. The "options" may
    /// also appear in any order (so long as one of the `App::get_matches*` methods is the last method
    /// called).
    ///
    /// # Examples
    ///
    /// ```no_run
    /// # use clap::{App, Arg};
    /// let m = App::new("My Program")
    ///     .author("Me, me@mail.com")
    ///     .version("1.0.2")
    ///     .about("Explains in brief what the program does")
    ///     .arg(
    ///         Arg::with_name("in_file").index(1)
    ///     )
    ///     .after_help("Longer explaination to appear after the options when \
    ///                  displaying the help information from --help or -h")
    ///     .get_matches();
    ///
    /// // Your program logic starts here...
    /// ```
    #[allow(missing_debug_implementations)]
    pub struct App<'a, 'b> where 'a: 'b {
        #[doc(hidden)]
        pub p: Parser<'a, 'b>
    }

    impl<'a, 'b> App<'a, 'b> {
        /// Creates a new instance of an application requiring a name. The name may be, but doesn't
        /// have to be same as the binary. The name will be displayed to the user when they request to
        /// print version or help and usage information.
        ///
        /// # Examples
        ///
        /// ```no_run
        /// # use clap::{App, Arg};
        /// let prog = App::new("My Program")
        /// # ;
        /// ```
        pub fn new<S: Into<String>>(n: S) -> Self { App { p: Parser::with_name(n.into()) } }

        /// Creates a new instace of `App` from a .yml (YAML) file. A full example of supported YAML
        /// objects can be found in `examples/17_yaml.rs` and `examples/17_yaml.yml`. One great use for
        /// using YAML is when supporting multiple languages and dialects, as each language could be a
        /// distinct YAML file and determined at compiletime via `cargo` "features" in your
        /// `Cargo.toml`
        ///
        /// In order to use this function you must compile `clap` with the `features = ["yaml"]` in
        /// your settings for the `[dependencies.clap]` table of your `Cargo.toml`
        ///
        /// **NOTE:** Due to how the YAML objects are built there is a convienience macro for loading
        /// the YAML file at compile time (relative to the current file, like modules work). That YAML
        /// object can then be passed to this function.
        ///
        /// # Panics
        ///
        /// The YAML file must be properly formatted or this function will panic!(). A good way to
        /// ensure this doesn't happen is to run your program with the `--help` switch. If this passes
        /// without error, you needn't worry because the YAML is properly formatted.
        ///
        /// # Examples
        ///
        /// The following example shows how to load a properly formatted YAML file to build an instnace
        /// of an `App` struct.
        ///
        /// ```ignore
        /// # use clap::App;
        /// let yml = load_yaml!("app.yml");
        /// let app = App::from_yaml(yml);
        ///
        /// // continued logic goes here, such as `app.get_matches()` etc.
        /// ```
        #[cfg(feature = "yaml")]
        pub fn from_yaml(yaml: &'a Yaml) -> App<'a, 'a> {
            App::from(yaml)
        }

        /// Sets a string of author(s) that will be displayed to the user when they
        /// request the help information with `--help` or `-h`.
        ///
        /// **Pro-tip:** If you turn on unstable features you can use `clap`s
        /// convienience macro `crate_authors!` to automatically set your
        /// application's author to the same thing as your crate at compile time.
        /// See the `examples/`
        /// directory for more information
        ///
        /// # Examples
        ///
        /// ```no_run
        /// # use clap::{App, Arg};
        /// App::new("myprog")
        ///      .author("Me, me@mymain.com")
        /// # ;
        /// ```
        pub fn author<S: Into<&'b str>>(mut self, author: S) -> Self {
            self.p.meta.author = Some(author.into());
            self
        }

        /// Overrides the system-determined binary name. This should only be used when absolutely
        /// neccessary, such as when the binary name for your application is misleading, or perhaps
        /// *not* how the user should invoke your program.
        ///
        /// **Pro-tip:** When building things such as third party `cargo` subcommands, this setting
        /// **should** be used!
        ///
        /// **NOTE:** This command **should not** be used for `SubCommand`s.
        ///
        /// # Examples
        ///
        /// ```no_run
        /// # use clap::{App, Arg};
        /// App::new("My Program")
        ///      .bin_name("my_binary")
        /// # ;
        /// ```
        pub fn bin_name<S: Into<String>>(mut self, name: S) -> Self {
            self.p.meta.bin_name = Some(name.into());
            self
        }

        /// Sets a string describing what the program does. This will be displayed when displaying help
        /// information.
        ///
        /// # Examples
        ///
        /// ```no_run
        /// # use clap::{App, Arg};
        /// App::new("myprog")
        ///     .about("Does really amazing things to great people")
        /// # ;
        /// ```
        pub fn about<S: Into<&'b str>>(mut self, about: S) -> Self {
            self.p.meta.about = Some(about.into());
            self
        }

        /// Adds additional help information to be displayed in addition to auto-generated help. This
        /// information is displayed **after** the auto-generated help information. This is often used
        /// to describe how to use the arguments, or caveats to be noted.
        ///
        /// # Examples
        ///
        /// ```no_run
        /// # use clap::App;
        /// App::new("myprog")
        ///     .after_help("Does really amazing things to great people...but be careful with -R")
        /// # ;
        /// ```
        pub fn after_help<S: Into<&'b str>>(mut self, help: S) -> Self {
            self.p.meta.more_help = Some(help.into());
            self
        }

        /// Adds additional help information to be displayed in addition to auto-generated help. This
        /// information is displayed **before** the auto-generated help information. This is often used
        /// for header information.
        ///
        /// # Examples
        ///
        /// ```no_run
        /// # use clap::App;
        /// App::new("myprog")
        ///     .before_help("Some info I'd like to appear before the help info")
        /// # ;
        /// ```
        pub fn before_help<S: Into<&'b str>>(mut self, help: S) -> Self {
            self.p.meta.pre_help = Some(help.into());
            self
        }

        /// Sets a string of the version number to be displayed when displaying version or help
        /// information.
        ///
        /// **Pro-tip:** Use `clap`s convienience macro `crate_version!` to automatically set your
        /// application's version to the same thing as your crate at compile time. See the `examples/`
        /// directory for more information
        ///
        /// # Examples
        ///
        /// ```no_run
        /// # use clap::{App, Arg};
        /// App::new("myprog")
        ///     .version("v0.1.24")
        /// # ;
        /// ```
        pub fn version<S: Into<&'b str>>(mut self, ver: S) -> Self {
            self.p.meta.version = Some(ver.into());
            self
        }

        /// Sets a custom usage string to override the auto-generated usage string.
        ///
        /// This will be displayed to the user when errors are found in argument parsing, or when you
        /// call `ArgMatches::usage`
        ///
        /// **CAUTION:** Using this setting disables `clap`s "context-aware" usage strings. After this
        /// setting is set, this will be the only usage string displayed to the user!
        ///
        /// **NOTE:** You do not need to specify the "USAGE: \n\t" portion, as that will
        /// still be applied by `clap`, you only need to specify the portion starting
        /// with the binary name.
        ///
        /// **NOTE:** This will not replace the entire help message, *only* the portion
        /// showing the usage.
        ///
        /// # Examples
        ///
        /// ```no_run
        /// # use clap::{App, Arg};
        /// App::new("myprog")
        ///     .usage("myapp [-clDas] <some_file>")
        /// # ;
        /// ```
        pub fn usage<S: Into<&'b str>>(mut self, usage: S) -> Self {
            self.p.meta.usage_str = Some(usage.into());
            self
        }

        /// Sets a custom help message and overrides the auto-generated one. This should only be used
        /// when the auto-generated message does not suffice.
        ///
        /// This will be displayed to the user when they use `--help` or `-h`
        ///
        /// **NOTE:** This replaces the **entire** help message, so nothing will be auto-generated.
        ///
        /// **NOTE:** This **only** replaces the help message for the current command, meaning if you
        /// are using subcommands, those help messages will still be auto-generated unless you
        /// specify a `.help()` for them as well.
        ///
        /// # Examples
        ///
        /// ```no_run
        /// # use clap::{App, Arg};
        /// App::new("myapp")
        ///     .help("myapp v1.0\n\
        ///            Does awesome things\n\
        ///            (C) me@mail.com\n\n\
        ///
        ///            USAGE: myapp <opts> <comamnd>\n\n\
        ///
        ///            Options:\n\
        ///            -h, --helpe      Dispay this message\n\
        ///            -V, --version    Display version info\n\
        ///            -s <stuff>       Do something with stuff\n\
        ///            -v               Be verbose\n\n\
        ///
        ///            Commmands:\n\
        ///            help             Prints this message\n\
        ///            work             Do some work")
        /// # ;
        /// ```
        pub fn help<S: Into<&'b str>>(mut self, help: S) -> Self {
            self.p.meta.help_str = Some(help.into());
            self
        }

        /// Sets the short version of the `help` argument without the preceding `-`.
        ///
        /// By default `clap` automatically assigns `h`, but this can be overridden by defining your
        /// own argument with a lowercase `h` as the `short`. `clap` lazily generates these help
        /// arguments **after** you've defined any arguments of your own.
        ///
        /// **NOTE:** Any leading `-` characters will be stripped, and only the first
        /// non `-` chacter will be used as the `short` version
        ///
        /// # Examples
        ///
        /// ```no_run
        /// # use clap::{App, Arg};
        /// App::new("myprog")
        ///     .help_short("H") // Using an uppercase `H` instead of the default lowercase `h`
        /// # ;
        /// ```
        pub fn help_short<S: AsRef<str> + 'b>(mut self, s: S) -> Self {
            self.p.help_short(s.as_ref());
            self
        }

        /// Sets the short version of the `version` argument without the preceding `-`.
        ///
        /// By default `clap` automatically assigns `V`, but this can be overridden by defining your
        /// own argument with a uppercase `V` as the `short`. `clap` lazily generates these version
        /// arguments **after** you've defined any arguments of your own.
        ///
        /// **NOTE:** Any leading `-` characters will be stripped, and only the first
        /// non `-` chacter will be used as the `short` version
        ///
        /// # Examples
        ///
        /// ```no_run
        /// # use clap::{App, Arg};
        /// App::new("myprog")
        ///     .version_short("v") // Using a lowercase `v` instead of the default capital `V`
        /// # ;
        /// ```
        pub fn version_short<S: AsRef<str>>(mut self, s: S) -> Self {
            self.p.version_short(s.as_ref());
            self
        }

        /// Sets the help template to be used, overriding the default format.
        ///
        /// Tags arg given inside curly brackets:
        /// Valid tags are:
        ///     * `{bin}`         - Binary name.
        ///     * `{version}`     - Version number.
        ///     * `{author}`      - Author information.
        ///     * `{usage}`       - Automatically generated or given usage string.
        ///     * `{all-args}`    - Help for all arguments (options, flags, positionals arguments,
        ///                         and subcommands) including titles.
        ///     * `{unified}`     - Unified help for options and flags.
        ///     * `{flags}`       - Help for flags.
        ///     * `{options}`     - Help for options.
        ///     * `{positionals}` - Help for positionals arguments.
        ///     * `{subcommands}` - Help for subcommands.
        ///     * `{after-help}`  - Help for flags.
        ///
        /// # Examples
        ///
        /// ```no_run
        /// # use clap::{App, Arg};
        /// App::new("myprog")
        ///     .version("1.0")
        ///     .template("{bin} ({version}) - {usage}")
        /// # ;
        /// ```
        /// **NOTE:**The template system is, on purpose, very simple. Therefore the tags have to writen
        /// in the lowercase and without spacing.
        pub fn template<S: Into<&'b str>>(mut self, s: S) -> Self {
            self.p.meta.template = Some(s.into());
            self
        }

        /// Enables a single Application level settings.
        ///
        /// See `AppSettings` for a full list of possibilities and examples.
        ///
        /// # Examples
        ///
        /// ```no_run
        /// # use clap::{App, Arg, AppSettings};
        /// App::new("myprog")
        ///     .setting(AppSettings::SubcommandRequired)
        ///     .setting(AppSettings::WaitOnError)
        /// # ;
        /// ```
        pub fn setting(mut self, setting: AppSettings) -> Self {
            self.p.set(setting);
            self
        }

        /// Enables multiple Application level settings
        ///
        /// See `AppSettings` for a full list of possibilities and examples.
        ///
        /// # Examples
        ///
        /// ```no_run
        /// # use clap::{App, Arg, AppSettings};
        /// App::new("myprog")
        ///     .settings(&[AppSettings::SubcommandRequired,
        ///                  AppSettings::WaitOnError])
        /// # ;
        /// ```
        pub fn settings(mut self, settings: &[AppSettings]) -> Self {
            for s in settings {
                self.p.set(*s);
            }
            self
        }

        /// Adds an argument to the list of valid possibilties.
        ///
        /// # Examples
        ///
        /// ```no_run
        /// # use clap::{App, Arg};
        /// App::new("myprog")
        ///     // Adding a single "flag" argument with a short and help text, using Arg::with_name()
        ///     .arg(
        ///         Arg::with_name("debug")
        ///            .short("d")
        ///            .help("turns on debugging mode")
        ///     )
        ///     // Adding a single "option" argument with a short, a long, and help text using the less
        ///     // verbose Arg::from_usage()
        ///     .arg(
        ///         Arg::from_usage("-c --config=[CONFIG] 'Optionally sets a config file to use'")
        ///     )
        /// # ;
        /// ```
        pub fn arg<A: Borrow<Arg<'a, 'b>> + 'a>(mut self, a: A) -> Self {
            self.p.add_arg(a.borrow());
            self
        }

        /// Adds multiple arguments to the list of valid possibilties
        ///
        /// # Examples
        ///
        /// ```no_run
        /// # use clap::{App, Arg};
        /// App::new("myprog")
        ///     .args(
        ///         &[Arg::from_usage("[debug] -d 'turns on debugging info'"),
        ///          Arg::with_name("input").index(1).help("the input file to use")]
        ///     )
        /// # ;
        /// ```
        pub fn args(mut self, args: &[Arg<'a, 'b>]) -> Self {
            for arg in args {
                self.p.add_arg(arg);
            }
            self
        }

        /// A convienience method for adding a single argument from a usage type string. The string
        /// used follows the same rules and syntax as `Arg::from_usage()`
        ///
        /// **NOTE:** The downside to using this method is that you can not set any additional
        /// properties of the `Arg` other than what `Arg::from_usage()` supports.
        ///
        /// # Examples
        ///
        /// ```no_run
        /// # use clap::{App, Arg};
        /// App::new("myprog")
        ///     .arg_from_usage("-c --config=<FILE> 'Sets a configuration file to use'")
        /// # ;
        /// ```
        pub fn arg_from_usage(mut self, usage: &'a str) -> Self {
            self.p.add_arg(&Arg::from_usage(usage));
            self
        }

        /// Adds multiple arguments at once from a usage string, one per line. See `Arg::from_usage()`
        /// for details on the syntax and rules supported.
        ///
        /// **NOTE:** Like `App::arg_from_usage()` the downside is you only set properties for the
        /// `Arg`s which `Arg::from_usage()` supports.
        ///
        /// # Examples
        ///
        /// ```no_run
        /// # use clap::{App, Arg};
        /// App::new("myprog")
        ///     .args_from_usage(
        ///         "-c --config=[FILE] 'Sets a configuration file to use'
        ///          [debug]... -d 'Sets the debugging level'
        ///          <FILE> 'The input file to use'"
        ///     )
        /// # ;
        /// ```
        pub fn args_from_usage(mut self, usage: &'a str) -> Self {
            for line in usage.lines() {
                let l = line.trim();
                if l.is_empty() { continue; }
                self.p.add_arg(&Arg::from_usage(l));
            }
            self
        }

        /// Adds an `ArgGroup` to the application. `ArgGroup`s are a family of related arguments. By
        /// placing them in a logical group, you can build easier requirement and exclusion rules. For
        /// instance, you can make an entire `ArgGroup` required, meaning that one (and *only* one) argument
        /// from that group must be present at runtime.
        ///
        /// You can also do things such as name an `ArgGroup` as a conflict to another argument.
        /// Meaning any of the arguments that belong to that group will cause a failure if present with
        /// the conflicting argument.
        ///
        /// Another added benfit of `ArgGroup`s is that you can extract a value from a group instead of
        /// determining exactly which argument was used.
        ///
        /// Finally, using `ArgGroup`s to ensure exclusion between arguments is another very common use
        ///
        /// # Examples
        ///
        /// The following example demonstrates using an `ArgGroup` to ensure that one, and only one, of
        /// the arguments from the specified group is present at runtime.
        ///
        /// ```no_run
        /// # use clap::{App, ArgGroup};
        /// App::new("app")
        ///     .args_from_usage(
        ///         "--set-ver [ver] 'set the version manually'
        ///          --major         'auto increase major'
        ///          --minor         'auto increase minor'
        ///          --patch         'auto increase patch'")
        ///     .group(ArgGroup::with_name("vers")
        ///          .args(&["set-ver", "major", "minor","patch"])
        ///          .required(true))
        /// # ;
        /// ```
        pub fn group(mut self, group: ArgGroup<'a>) -> Self {
            self.p.add_group(group);
            self
        }

        /// Adds multiple `ArgGroup`s to the application at once.
        ///
        /// # Examples
        ///
        /// ```no_run
        /// # use clap::{App, ArgGroup};
        /// App::new("app")
        ///     .args_from_usage(
        ///         "--set-ver [ver] 'set the version manually'
        ///          --major         'auto increase major'
        ///          --minor         'auto increase minor'
        ///          --patch         'auto increase patch'
        ///          -c [FILE]       'a config file'
        ///          -i [IFACE]      'an interface'")
        ///     .groups(&[
        ///         ArgGroup::with_name("vers")
        ///             .args(&["set-ver", "major", "minor","patch"])
        ///             .required(true),
        ///         ArgGroup::with_name("input")
        ///             .args(&["c", "i"])
        ///     ])
        /// # ;
        /// ```
        pub fn groups(mut self, groups: &[ArgGroup<'a>]) -> Self {
            for g in groups {
                self = self.group(g.into());
            }
            self
        }

        /// Adds a subcommand to the list of valid possibilties. Subcommands are effectively sub-apps,
        /// because they can contain their own arguments, subcommands, version, usage, etc. They also
        /// function just like apps, in that they get their own auto generated help, version, and
        /// usage.
        ///
        /// # Examples
        ///
        /// ```no_run
        /// # use clap::{App, Arg, SubCommand};
        /// App::new("myprog")
        ///     .subcommand(SubCommand::with_name("config")
        ///         .about("Controls configuration features")
        ///         .arg_from_usage("<config> 'Required configuration file to use'"))
        /// # ;
        /// ```
        pub fn subcommand(mut self, subcmd: App<'a, 'b>) -> Self {
            self.p.add_subcommand(subcmd);
            self
        }

        /// Adds multiple subcommands to the list of valid possibilties by iterating over a Vec of
        /// `SubCommand`s
        ///
        /// # Examples
        ///
        /// ```no_run
        /// # use clap::{App, Arg, SubCommand};
        /// # App::new("myprog")
        /// .subcommands( vec![
        ///        SubCommand::with_name("config").about("Controls configuration functionality")
        ///                                 .arg(Arg::with_name("config_file").index(1)),
        ///        SubCommand::with_name("debug").about("Controls debug functionality")])
        /// # ;
        /// ```
        pub fn subcommands<I>(mut self, subcmds: I) -> Self
            where I: IntoIterator<Item = App<'a, 'b>>
        {
            for subcmd in subcmds.into_iter() {
                self.p.add_subcommand(subcmd);
            }
            self
        }

        /// Allows custom ordering of subcommands within the help message. Subcommands with a lower
        /// value will be displayed first in the help message. This is helpful when one would like to
        /// emphasise frequently used subcommands, or prioritize those towards the top of the list.
        /// Duplicate values **are** allowed. Subcommands with duplicate display orders will be
        /// displayed in alphabetical order.
        ///
        /// **NOTE:** The default is 999 for all subcommands.
        ///
        /// # Examples
        ///
        /// ```rust
        /// # use clap::{App, SubCommand};
        /// let m = App::new("cust-ord")
        ///     .subcommand(SubCommand::with_name("alpha") // typically subcommands are grouped
        ///                                                // alphabetically by name. Subcommands
        ///                                                // without a display_order have a value of
        ///                                                // 999 and are displayed alphabetically with
        ///                                                // all other 999 subcommands
        ///         .about("Some help and text"))
        ///     .subcommand(SubCommand::with_name("beta")
        ///         .display_order(1)   // In order to force this subcommand to appear *first*
        ///                             // all we have to do is give it a value lower than 999.
        ///                             // Any other subcommands with a value of 1 will be displayed
        ///                             // alphabetically with this one...then 2 values, then 3, etc.
        ///         .about("I should be first!"))
        ///     .get_matches_from(vec![
        ///         "cust-ord", "--help"
        ///     ]);
        /// ```
        ///
        /// The above example displays the following help message
        ///
        /// ```ignore
        /// cust-ord
        ///
        /// USAGE:
        ///     cust-ord [FLAGS] [OPTIONS]
        ///
        /// FLAGS:
        ///     -h, --help       Prints help information
        ///     -V, --version    Prints version information
        ///
        /// SUBCOMMANDS:
        ///     beta    I should be first!
        ///     alpha   Some help and text
        /// ```
        pub fn display_order(mut self, ord: usize) -> Self {
            self.p.meta.disp_ord = ord;
            self
        }

        /// Prints the full help message to `io::stdout()` using a `BufWriter`
        ///
        /// # Examples
        ///
        /// ```no_run
        /// # use clap::App;
        /// let app = App::new("myprog");
        /// app.print_help();
        /// ```
        pub fn print_help(&self) -> ClapResult<()> {
            let out = io::stdout();
            let mut buf_w = BufWriter::new(out.lock());
            self.write_help(&mut buf_w)
        }

        /// Writes the full help message to the user to a `io::Write` object
        ///
        /// # Examples
        ///
        /// ```no_run
        /// # use clap::App;
        /// use std::io;
        /// let mut app = App::new("myprog");
        /// let mut out = io::stdout();
        /// app.write_help(&mut out).ok().expect("failed to write to stdout");
        /// ```
        pub fn write_help<W: Write>(&self, w: &mut W) -> ClapResult<()> {
            Help::write_app_help(w, &self)
        }

        /// Starts the parsing process, upon a failed parse an error will be displayed to the user and
        /// the process with exit with the appropriate error code. By default this method gets matches
        /// from `env::args_os`
        ///
        /// # Examples
        ///
        /// ```no_run
        /// # use clap::{App, Arg};
        /// let matches = App::new("myprog")
        ///     // Args and options go here...
        ///     .get_matches();
        /// ```
        pub fn get_matches(self) -> ArgMatches<'a> {
            self.get_matches_from(&mut env::args_os())
        }

        /// Starts the parsing process. This method will return a `Result` type instead of exiting the
        /// the process on failed parse. By default this method gets matches
        /// from `env::args_os`
        ///
        /// **NOTE:** This method WILL NOT exit when `--help` or `--version` (or short versions) are
        /// used. It will return an error, where the `kind` is a `ErrorKind::HelpDisplayed`
        /// or `ErrorKind::VersionDisplayed` respectively. You must call `error.exit()` or
        /// perform a `std::process::exit`.
        ///
        /// # Examples
        ///
        /// ```no_run
        /// # use clap::{App, Arg};
        /// let matches = App::new("myprog")
        ///     // Args and options go here...
        ///     .get_matches_safe()
        ///     .unwrap_or_else( |e| e.exit() );
        /// ```
        pub fn get_matches_safe(self) -> ClapResult<ArgMatches<'a>> {
            // Start the parsing
            self.get_matches_from_safe(&mut env::args_os())
        }

        /// Starts the parsing process. Like `App::get_matches` this method does not return a `Result`
        /// and will automatically exit with an error message. This method, however, lets you specify
        /// what iterator to use when performing matches, such as a `Vec` of your making.
        ///
        /// **NOTE:** The first argument will be parsed as the binary name unless
        /// `AppSettings::NoBinaryName` is used
        ///
        /// # Examples
        ///
        /// ```no_run
        /// # use clap::{App, Arg};
        /// let arg_vec = vec!["my_prog", "some", "args", "to", "parse"];
        ///
        /// let matches = App::new("myprog")
        ///     // Args and options go here...
        ///     .get_matches_from(arg_vec);
        /// ```
        pub fn get_matches_from<I, T>(mut self, itr: I) -> ArgMatches<'a>
            where I: IntoIterator<Item = T>,
                  T: Into<OsString>
        {
            self.get_matches_from_safe_borrow(itr).unwrap_or_else(|e| {
                // Otherwise, write to stderr and exit
                self.maybe_wait_for_exit(e);
            })
        }

        /// Starts the parsing process. A combination of `App::get_matches_from`, and
        /// `App::get_matches_safe`
        ///
        /// **NOTE:** This method WILL NOT exit when `--help` or `--version` (or short versions) are
        /// used. It will return an error, where the `kind` is a `ErrorKind::HelpDisplayed`
        /// or `ErrorKind::VersionDisplayed` respectively. You must call `error.exit()` or
        /// perform a `std::process::exit` yourself.
        ///
        /// **NOTE:** The first argument will be parsed as the binary name unless
        /// `AppSettings::NoBinaryName` is used
        ///
        /// # Examples
        ///
        /// ```no_run
        /// # use clap::{App, Arg};
        /// let arg_vec = vec!["my_prog", "some", "args", "to", "parse"];
        ///
        /// let matches = App::new("myprog")
        ///     // Args and options go here...
        ///     .get_matches_from_safe(arg_vec)
        ///     .unwrap_or_else( |e| { panic!("An error occurs: {}", e) });
        /// ```
        pub fn get_matches_from_safe<I, T>(mut self, itr: I) -> ClapResult<ArgMatches<'a>>
            where I: IntoIterator<Item = T>,
                  T: Into<OsString>
        {
            self.get_matches_from_safe_borrow(itr)
        }

        /// Starts the parsing process without consuming the `App` struct `self`. This is normally not
        /// the desired functionality, instead prefer `App::get_matches_from_safe` which *does*
        /// consume `self`.
        ///
        /// **NOTE:** The first argument will be parsed as the binary name unless
        /// `AppSettings::NoBinaryName` is used
        ///
        /// # Examples
        ///
        /// ```no_run
        /// # use clap::{App, Arg};
        /// let arg_vec = vec!["my_prog", "some", "args", "to", "parse"];
        ///
        /// let mut app = App::new("myprog");
        ///     // Args and options go here...
        /// let matches = app.get_matches_from_safe_borrow(arg_vec)
        ///     .unwrap_or_else( |e| { panic!("An error occurs: {}", e) });
        /// ```
        pub fn get_matches_from_safe_borrow<I, T>(&mut self, itr: I) -> ClapResult<ArgMatches<'a>>
            where I: IntoIterator<Item = T>,
                  T: Into<OsString>
        {
            // Verify all positional assertions pass
            self.p.verify_positionals();
            // If there are global arguments, we need to propgate them down to subcommands
            // before parsing incase we run into a subcommand
            self.p.propogate_globals();

            let mut matcher = ArgMatcher::new();

            let mut it = itr.into_iter();
            // Get the name of the program (argument 1 of env::args()) and determine the
            // actual file
            // that was used to execute the program. This is because a program called
            // ./target/release/my_prog -a
            // will have two arguments, './target/release/my_prog', '-a' but we don't want
            // to display
            // the full path when displaying help messages and such
            if !self.p.is_set(AppSettings::NoBinaryName) {
                if let Some(name) = it.next() {
                    let bn_os = name.into();
                    let p = Path::new(&*bn_os);
                    if let Some(f) = p.file_name() {
                        if let Some(s) = f.to_os_string().to_str() {
                            if let None = self.p.meta.bin_name {
                                self.p.meta.bin_name = Some(s.to_owned());
                            }
                        }
                    }
                }
            }

            // do the real parsing
            if let Err(e) = self.p.get_matches_with(&mut matcher, &mut it) {
                return Err(e);
            }

            Ok(matcher.into())
        }

        // Re-implements ClapError::exit except it checks if we should wait for input before exiting
        // since ClapError doesn't have that info and the error message must be printed before exiting
        fn maybe_wait_for_exit(&self, e: Error) -> ! {
            if e.use_stderr() {
                wlnerr!("{}", e.message);
                if self.p.is_set(AppSettings::WaitOnError) {
                    wlnerr!("\nPress [ENTER] / [RETURN] to continue...");
                    let mut s = String::new();
                    let i = io::stdin();
                    i.lock().read_line(&mut s).unwrap();
                }
                process::exit(1);
            }

            e.exit()
        }
    }

    #[cfg(feature = "yaml")]
    impl<'a> From<&'a Yaml> for App<'a, 'a> {
        fn from(mut yaml: &'a Yaml) -> Self {
            use args::SubCommand;
            // We WANT this to panic on error...so expect() is good.
            let mut is_sc = None;
            let mut a = if let Some(name) = yaml["name"].as_str() {
                App::new(name)
            } else {
                let yaml_hash = yaml.as_hash().unwrap();
                let sc_key = yaml_hash.keys().nth(0).unwrap();
                is_sc = Some(yaml_hash.get(sc_key).unwrap());
                App::new(sc_key.as_str().unwrap())
            };
            yaml = if let Some(sc) = is_sc {
                sc
            } else {
                yaml
            };
            if let Some(v) = yaml["version"].as_str() {
                a = a.version(v);
            }
            if let Some(v) = yaml["author"].as_str() {
                a = a.author(v);
            }
            if let Some(v) = yaml["bin_name"].as_str() {
                a = a.bin_name(v);
            }
            if let Some(v) = yaml["about"].as_str() {
                a = a.about(v);
            }
            if let Some(v) = yaml["after_help"].as_str() {
                a = a.after_help(v);
            }
            if let Some(v) = yaml["display_order"].as_i64() {
                a = a.display_order(v as usize);
            }
            if let Some(v) = yaml["usage"].as_str() {
                a = a.usage(v);
            }
            if let Some(v) = yaml["help"].as_str() {
                a = a.help(v);
            }
            if let Some(v) = yaml["help_short"].as_str() {
                a = a.help_short(v);
            }
            if let Some(v) = yaml["version_short"].as_str() {
                a = a.version_short(v);
            }
            if let Some(v) = yaml["settings"].as_vec() {
                for ys in v {
                    if let Some(s) = ys.as_str() {
                        a = a.setting(s.parse().ok().expect("unknown AppSetting found in YAML file"));
                    }
                }
            }
            if let Some(v) = yaml["args"].as_vec() {
                for arg_yaml in v {
                    a = a.arg(Arg::from_yaml(&arg_yaml.as_hash().unwrap()));
                }
            }
            if let Some(v) = yaml["subcommands"].as_vec() {
                for sc_yaml in v {
                    a = a.subcommand(SubCommand::from_yaml(&sc_yaml));
                }
            }
            if let Some(v) = yaml["groups"].as_vec() {
                for ag_yaml in v {
                    a = a.group(ArgGroup::from(ag_yaml.as_hash().unwrap()));
                }
            }

            a
        }
    }

    impl<'a, 'b> Clone for App<'a, 'b> {
        fn clone(&self) -> Self {
            App {
                p: self.p.clone(),
            }
        }
    }

    impl<'n, 'e> AnyArg<'n, 'e> for App<'n, 'e> {
        fn name(&self) -> &'n str {
            unreachable!("App struct does not support AnyArg::name, this is a bug!")
        }
        fn overrides(&self) -> Option<&[&'e str]> { None }
        fn requires(&self) -> Option<&[&'e str]> { None }
        fn blacklist(&self) -> Option<&[&'e str]> { None }
        fn required_unless(&self) -> Option<&[&'e str]> { None }
        fn val_names(&self) -> Option<&VecMap<&'e str>> { None }
        fn is_set(&self, _: ArgSettings) -> bool { false }
        fn set(&mut self, _: ArgSettings) {
            unreachable!("App struct does not support AnyArg::set, this is a bug!")
        }
        fn has_switch(&self) -> bool { false }
        fn max_vals(&self) -> Option<u64> { None }
        fn num_vals(&self) -> Option<u64> { None }
        fn possible_vals(&self) -> Option<&[&'e str]> { None }
        fn validator(&self) -> Option<&Rc<Fn(String) -> StdResult<(), String>>> { None }
        fn min_vals(&self) -> Option<u64> { None }
        fn short(&self) -> Option<char> { None }
        fn long(&self) -> Option<&'e str> { None }
        fn val_delim(&self) -> Option<char> { None }
        fn takes_value(&self) -> bool { true }
        fn help(&self) -> Option<&'e str> { self.p.meta.about }
        fn default_val(&self) -> Option<&'n str> { None }
        fn longest_filter(&self) -> bool { true }
    }

    impl<'n, 'e> fmt::Display for App<'n, 'e> {
        fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
            write!(f, "{}", self.p.meta.name)
        }
    }

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