clap/src/macros.rs

// De-duplication macro used in src/app.rs
macro_rules! get_help {
    ($opt:ident) => {
        if let Some(h) = $opt.help {
            format!("{}{}", h,
                if let Some(ref pv) = $opt.possible_vals {
                    let mut pv_s = pv.iter().fold(String::with_capacity(50), |acc, name| {
                        acc + &format!(" {}",name)[..]
                    });
                    pv_s.shrink_to_fit();
                    format!(" [values:{}]", &pv_s[..])
                }else{"".to_owned()})
        } else {
            "    ".to_owned()
        }
    };
}

// De-duplication macro used in src/app.rs
macro_rules! parse_group_reqs {
    ($me:ident, $arg:ident) => {
        for ag in $me.groups.values() {
            let mut found = false;
            for name in ag.args.iter() {
                if name == &$arg.name {
                    $me.required.remove(ag.name);
                    if let Some(ref reqs) = ag.requires {
                        for r in reqs {
                            $me.required.insert(r);
                        }
                    }
                    if let Some(ref bl) = ag.conflicts {
                        for b in bl {
                            $me.blacklist.insert(b);
                        }
                    }
                    found = true;
                    break;
                }
            }
            if found {
                for name in ag.args.iter() {
                    if name == &$arg.name { continue }
                    $me.required.remove(name);
                    $me.blacklist.insert(name);
                }
            }
        }
    };
}

// De-duplication macro used in src/app.rs
macro_rules! validate_reqs {
    ($me:ident, $t:ident, $m:ident, $n:ident) => {
        if let Some(a) = $me.$t.get($n) {
            if let Some(ref bl) = a.blacklist {
                for n in bl.iter() {
                    if $m.args.contains_key(n) {
                        return false
                    } else if $me.groups.contains_key(n) {
                        let grp = $me.groups.get(n).unwrap();
                        for an in grp.args.iter() {
                            if $m.args.contains_key(an) {
                                return false
                            }
                        }
                    }
                }
            }
        }
    };
}

// Thanks to bluss and flan3002 in #rust IRC
//
// Helps with rightward drift when iterating over something and matching each item.
macro_rules! for_match {
    ($it:ident, $($p:pat => $($e:expr);+),*) => {
        for i in $it {
            match i {
            $(
                $p => { $($e)+ }
            )*
            }
        }
    };
}

/// Convenience macro getting a typed value `T` where `T` implements `std::str::FromStr`
/// This macro returns a `Result<T,String>` which allows you as the developer to decide
/// what you'd like to do on a failed parse. There are two types of errors, parse failures
/// and those where the argument wasn't present (such as a non-required argument).
///
/// You can use it to get a single value, or a `Vec<T>` with the `values_of()`
///
/// **NOTE:** Be cautious, as since this a macro invocation it's not exactly like
/// standard syntax.
///
///
/// # Example single value
///
/// ```no_run
/// # #[macro_use]
/// # extern crate clap;
/// # use clap::App;
/// # fn main() {
/// let matches = App::new("myapp")
///               .arg_from_usage("[length] 'Set the length to use as a pos whole num, i.e. 20'")
///               .get_matches();
/// let len = value_t!(matches.value_of("length"), u32)
///                 .unwrap_or_else(|e|{
///                     println!("{}",e);
///                     std::process::exit(1)
///                 });
///
/// println!("{} + 2: {}", len, len + 2);
/// # }
/// ```
///
///
/// # Example multiple values
///
/// ```no_run
/// # #[macro_use]
/// # extern crate clap;
/// # use clap::App;
/// # fn main() {
/// let matches = App::new("myapp")
///               .arg_from_usage("[seq]... 'A sequence of pos whole nums, i.e. 20 45'")
///               .get_matches();
/// for v in value_t!(matches.values_of("seq"), u32)
///             .unwrap_or_else(|e|{
///                 println!("{}",e);
///                 std::process::exit(1)
///             }) {
///     println!("{} + 2: {}", v, v + 2);
/// }
/// # }
/// ```
#[macro_export]
macro_rules! value_t {
    ($m:ident.value_of($v:expr), $t:ty) => {
        match $m.value_of($v) {
            Some(v) => {
                match v.parse::<$t>() {
                    Ok(val) => Ok(val),
                    Err(_)  => Err(format!("{} isn't a valid {}",v,stringify!($t))),
                }
            },
            None => Err(format!("Argument \"{}\" not found", $v))
        }
    };
    ($m:ident.values_of($v:expr), $t:ty) => {
        match $m.values_of($v) {
            Some(ref v) => {
                let mut tmp = Vec::with_capacity(v.len());
                let mut err = None;
                for pv in v {
                    match pv.parse::<$t>() {
                        Ok(rv) => tmp.push(rv),
                        Err(e) => {
                            err = Some(format!("{} isn't a valid {}\n{}",pv,stringify!($t),e));
                            break
                        }
                    }
                }
                match err {
                    Some(e) => Err(e),
                    None => Ok(tmp)
                }
            },
            None => Err(format!("Argument \"{}\" not found", $v))
        }
    };
}

/// Convenience macro getting a typed value `T` where `T` implements `std::str::FromStr`
/// This macro returns a `T` or `Vec<T>` or exits with a usage string upon failure. This
/// removes some of the boiler plate to handle failures from value_t! above.
///
/// You can use it to get a single value `T`, or a `Vec<T>` with the `values_of()`
///
/// **NOTE:** This should only be used on required arguments, as it can be confusing to the user
/// why they are getting error messages when it appears they're entering all required argumetns.
///
/// **NOTE:** Be cautious, as since this a macro invocation it's not exactly like
/// standard syntax.
///
///
/// # Example single value
///
/// ```no_run
/// # #[macro_use]
/// # extern crate clap;
/// # use clap::App;
/// # fn main() {
/// let matches = App::new("myapp")
///               .arg_from_usage("[length] 'Set the length to use as a pos whole num, i.e. 20'")
///               .get_matches();
/// let len = value_t_or_exit!(matches.value_of("length"), u32);
///
/// println!("{} + 2: {}", len, len + 2);
/// # }
/// ```
///
///
/// # Example multiple values
///
/// ```no_run
/// # #[macro_use]
/// # extern crate clap;
/// # use clap::App;
/// # fn main() {
/// let matches = App::new("myapp")
///                   .arg_from_usage("[seq]... 'A sequence of pos whole nums, i.e. 20 45'")
///                   .get_matches();
/// for v in value_t_or_exit!(matches.values_of("seq"), u32) {
///     println!("{} + 2: {}", v, v + 2);
/// }
/// # }
/// ```
#[macro_export]
macro_rules! value_t_or_exit {
    ($m:ident.value_of($v:expr), $t:ty) => {
        match $m.value_of($v) {
            Some(v) => {
                match v.parse::<$t>() {
                    Ok(val) => val,
                    Err(e)  => {
                        println!("{} isn't a valid {}\n{}\n{}\nPlease re-run with --help for \
                            more information",
                            v,
                            stringify!($t),
                            e,
                            $m.usage());
                        ::std::process::exit(1);
                    }
                }
            },
            None => {
                println!("Argument \"{}\" not found or is not valid\n{}\nPlease re-run with \
                    --help for more information",
                    $v,
                    $m.usage());
                ::std::process::exit(1);
            }
        }
    };
    ($m:ident.values_of($v:expr), $t:ty) => {
        match $m.values_of($v) {
            Some(ref v) => {
                let mut tmp = Vec::with_capacity(v.len());
                for pv in v {
                    match pv.parse::<$t>() {
                        Ok(rv) => tmp.push(rv),
                        Err(_)  => {
                            println!("{} isn't a valid {}\n{}\nPlease re-run with --help for more \
                                information",
                                pv,
                                stringify!($t),
                                $m.usage());
                            ::std::process::exit(1);
                        }
                    }
                }
                tmp
            },
            None => {
                println!("Argument \"{}\" not found or is not valid\n{}\nPlease re-run with \
                    --help for more information",
                    $v,
                    $m.usage());
                ::std::process::exit(1);
            }
        }
    };
}

/// Convenience macro generated a simple enum with variants to be used as a type when parsing
/// arguments.
///
/// # Example
///
/// ```no_run
/// # #[macro_use]
/// # extern crate clap;
/// # use clap::{App, Arg};
/// simple_enum!{Foo => Bar, Baz, Qux}
/// // Foo enum can now be used via Foo::Bar, or Foo::Baz, etc
/// // and implements std::str::FromStr to use with the value_t! macros
/// fn main() {
///     let enum_vals = ["Bar", "Baz", "Qux"];
///     let m = App::new("app")
///                 .arg(Arg::from_usage("<foo> 'the foo'")
///                     .possible_values(&enum_vals))
///                 .get_matches();
///     let f = value_t_or_exit!(m.value_of("foo"), Foo);
///
///     // Use f like any other Foo variant...
/// }
/// ```
#[macro_export]
macro_rules! simple_enum {
    ($e:ident => $($v:ident),+) => {
        enum $e {
            $($v),+
        }

        impl ::std::str::FromStr for $e {
            type Err = String;

            fn from_str(s: &str) -> Result<Self,Self::Err> {
                match s {
                    $(stringify!($v) => Ok($e::$v),)+
                    _                => Err({
                                            let v = vec![
                                                $(stringify!($v),)+
                                            ];
                                            format!("valid:{}",
                                                v.iter().fold(String::new(), |a, i| {
                                                    a + &format!(" {}", i)[..]
                                                }))
                                        })
                }
            }
        }
    };
}

/// Convenience macro to generate more complete enums with variants to be used as a type when
/// parsing arguments.
///
/// These enums support pub (or not) and use of the #[derive()] traits
///
///
/// # Example
///
/// ```no_run
/// # #[macro_use]
/// # extern crate clap;
/// # use clap::{App, Arg};
/// arg_enum!{
///     #[derive(Debug)]
///     pub enum Foo {
///         Bar,
///         Baz,
///         Qux
///     }
/// }
/// // Foo enum can now be used via Foo::Bar, or Foo::Baz, etc
/// // and implements std::str::FromStr to use with the value_t! macros
/// fn main() {
///     let m = App::new("app")
///                 .arg_from_usage("<foo> 'the foo'")
///                 .get_matches();
///     let f = value_t_or_exit!(m.value_of("foo"), Foo);
///
///     // Use f like any other Foo variant...
/// }
/// ```
#[macro_export]
macro_rules! arg_enum {
    (enum $e:ident { $($v:ident),+ } ) => {
        enum $e {
            $($v),+
        }

        impl ::std::str::FromStr for $e {
            type Err = String;

            fn from_str(s: &str) -> Result<Self,Self::Err> {
                match s {
                    $(stringify!($v) => Ok($e::$v),)+
                    _                => Err({
                                            let v = vec![
                                                $(stringify!($v),)+
                                            ];
                                            format!("valid:{}",
                                                v.iter().fold(String::new(), |a, i| {
                                                    a + &format!(" {}", i)[..]
                                                }))
                                        })
                }
            }
        }
    };
    (pub enum $e:ident { $($v:ident),+ } ) => {
        pub enum $e {
            $($v),+
        }

        impl ::std::str::FromStr for $e {
            type Err = String;

            fn from_str(s: &str) -> Result<Self,Self::Err> {
                match s {
                    $(stringify!($v) => Ok($e::$v),)+
                    _                => Err({
                                            let v = vec![
                                                $(stringify!($v),)+
                                            ];
                                            format!("valid:{}",
                                                v.iter().fold(String::new(), |a, i| {
                                                    a + &format!(" {}", i)[..]
                                                }))
                                        })
                }
            }
        }
    };
    (#[derive($($d:ident),+)] enum $e:ident { $($v:ident),+ } ) => {
        #[derive($($d,)+)]
        enum $e {
            $($v),+
        }

        impl ::std::str::FromStr for $e {
            type Err = String;

            fn from_str(s: &str) -> Result<Self,Self::Err> {
                match s {
                    $(stringify!($v) => Ok($e::$v),)+
                    _                => Err({
                                            let v = vec![
                                                $(stringify!($v),)+
                                            ];
                                            format!("valid:{}",
                                                v.iter().fold(String::new(), |a, i| {
                                                    a + &format!(" {}", i)[..]
                                                }))
                                        })
                }
            }
        }
    };
    (#[derive($($d:ident),+)] pub enum $e:ident { $($v:ident),+ } ) => {
        #[derive($($d,)+)]
        pub enum $e {
            $($v),+
        }

        impl ::std::str::FromStr for $e {
            type Err = String;

            fn from_str(s: &str) -> Result<Self,Self::Err> {
                match s {
                    $(stringify!($v) => Ok($e::$v),)+
                    _                => Err({
                                            let v = vec![
                                                $(stringify!($v),)+
                                            ];
                                            format!("valid:{}",
                                                v.iter().fold(String::new(), |a, i| {
                                                    a + &format!(" {}", i)[..]
                                                }))
                                        })
                }
            }
        }
    };
}

/// Allows you pull the version for an from your Cargo.toml as MAJOR.MINOR.PATCH_PKGVERSION_PRE
///
/// # Example
/// ```no_run
/// # #[macro_use]
/// # extern crate clap;
/// # use clap::App;
/// # fn main() {
///     let m = App::new("app")
///                 .version(&crate_version!()[..])
///                 .get_matches();
/// # }
/// ```
#[macro_export]
macro_rules! crate_version {
    () => {
        format!("{}.{}.{}{}",
            env!("CARGO_PKG_VERSION_MAJOR"),
            env!("CARGO_PKG_VERSION_MINOR"),
            env!("CARGO_PKG_VERSION_PATCH"),
            option_env!("CARGO_PKG_VERSION_PRE").unwrap_or(""))
    }
}