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docs(Arg Indices): adds the documentation for the arg index querying …
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@kbknapp
kbknapp committed Mar 3, 2018
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183 changes: 183 additions & 0 deletions src/args/arg_matches.rs
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Expand Up @@ -364,6 +364,189 @@ impl<'a> ArgMatches<'a> {
self.args.get(name.as_ref()).map_or(0, |a| a.occurs)
}

/// Gets the starting index of the argument in respect to all other arguments. Indices are
/// similar to argv indices, but are not exactly 1:1.
///
/// For flags (i.e. those arguments which don't have an associated value), indices refer
/// to occurrence of the switch, such as `-f`, or `--flag`. However, for options the indices
/// refer to the *values* `-o val` would therefore not represent two distinct indices, only the
/// index for `val` would be recorded. This is by design.
///
/// Besides the flag/option descrepancy, the primary difference between an argv index and clap
/// index, is that clap continues counting once all arguments have properly seperated, whereas
/// an argv index does not.
///
/// The examples should clear this up.
///
/// *NOTE:* If an argument is allowed multiple times, this method will only give the *first*
/// index.
///
/// # Examples
///
/// The argv indices are listed in the comments below. See how they correspond to the clap
/// indices. Note that if it's not listed in a clap index, this is becuase it's not saved in
/// in an `ArgMatches` struct for querying.
///
/// ```rust
/// # use clap::{App, Arg};
/// let m = App::new("myapp")
/// .arg(Arg::with_name("flag")
/// .short("f"))
/// .arg(Arg::with_name("option")
/// .short("o")
/// .takes_value(true))
/// .get_matches_from(vec!["myapp", "-f", "-o", "val"]);
/// // ARGV idices: ^0 ^1 ^2 ^3
/// // clap idices: ^1 ^3
///
/// assert_eq!(m.index_of("flag"), Some(1));
/// assert_eq!(m.index_of("option"), Some(3));
/// ```
///
/// Now notice, if we use one of the other styles of options:
///
/// ```rust
/// # use clap::{App, Arg};
/// let m = App::new("myapp")
/// .arg(Arg::with_name("flag")
/// .short("f"))
/// .arg(Arg::with_name("option")
/// .short("o")
/// .takes_value(true))
/// .get_matches_from(vec!["myapp", "-f", "-o=val"]);
/// // ARGV idices: ^0 ^1 ^2
/// // clap idices: ^1 ^3
///
/// assert_eq!(m.index_of("flag"), Some(1));
/// assert_eq!(m.index_of("option"), Some(2));
/// ```
///
/// Things become much more complicated, or clear if we look at a more complex combination of
/// flags. Let's also throw in the final option style for good measure.
///
/// ```rust
/// # use clap::{App, Arg};
/// let m = App::new("myapp")
/// .arg(Arg::with_name("flag")
/// .short("f"))
/// .arg(Arg::with_name("flag2")
/// .short("F"))
/// .arg(Arg::with_name("flag3")
/// .short("z"))
/// .arg(Arg::with_name("option")
/// .short("o")
/// .takes_value(true))
/// .get_matches_from(vec!["myapp", "-fzF", "-oval"]);
/// // ARGV idices: ^0 ^1 ^2
/// // clap idices: ^1,2,3 ^5
/// //
/// // clap sees the above as 'myapp -f -z -F -o val'
/// // ^0 ^1 ^2 ^3 ^4 ^5
/// assert_eq!(m.index_of("flag"), Some(1));
/// assert_eq!(m.index_of("flag2"), Some(3));
/// assert_eq!(m.index_of("flag3"), Some(2));
/// assert_eq!(m.index_of("option"), Some(5));
/// ```
///
/// One final combination of flags/options to see how they combine:
///
/// ```rust
/// # use clap::{App, Arg};
/// let m = App::new("myapp")
/// .arg(Arg::with_name("option")
/// .short("o")
/// .takes_value(true)
/// .multiple(true))
/// .get_matches_from(vec!["myapp", "-ozFoval"]);
/// // ARGV idices: ^0 ^1
/// // clap idices: ^1,2,3^5
/// //
/// // clap sees the above as 'myapp -f -z -F -o val'
/// // ^0 ^1 ^2 ^3 ^4 ^5
/// assert_eq!(m.index_of("flag"), Some(1));
/// assert_eq!(m.index_of("flag2"), Some(3));
/// assert_eq!(m.index_of("flag3"), Some(2));
/// assert_eq!(m.index_of("option"), Some(5));
/// ```
///
/// The last part to mention is when values are sent in multiple groups with a [delimiter].
///
/// ```rust
/// # use clap::{App, Arg};
/// let m = App::new("myapp")
/// .arg(Arg::with_name("option")
/// .short("o")
/// .takes_value(true)
/// .multiple(true))
/// .get_matches_from(vec!["myapp", "-o=val1,val2,val3"]);
/// // ARGV idices: ^0 ^1
/// // clap idices: ^2 ^3 ^4
/// //
/// // clap sees the above as 'myapp -o val1 val2 val3'
/// // ^0 ^1 ^2 ^3 ^4
/// assert_eq!(m.index_of("option"), Some(2));
/// ```
/// [`ArgMatches`]: ./struct.ArgMatches.html
/// [delimiter]: ./struct.Arg.html#method.value_delimiter
pub fn index_of<S: AsRef<str>>(&self, name: S) -> Option<&str> {
unimplemented!()
}

/// Gets all indices of the argument in respect to all other arguments. Indices are
/// similar to argv indices, but are not exactly 1:1.
///
/// For flags (i.e. those arguments which don't have an associated value), indices refer
/// to occurrence of the switch, such as `-f`, or `--flag`. However, for options the indices
/// refer to the *values* `-o val` would therefore not represent two distinct indices, only the
/// index for `val` would be recorded. This is by design.
///
/// *NOTE:* For more information about how clap indices compare to argv indices, see
/// [`ArgMatches::index_of`]
///
/// # Examples
///
/// ```rust
/// # use clap::{App, Arg};
/// let m = App::new("myapp")
/// .arg(Arg::with_name("option")
/// .short("o")
/// .takes_value(true)
/// .multiple(true))
/// .get_matches_from(vec!["myapp", "-o=val1,val2,val3"]);
/// // ARGV idices: ^0 ^1
/// // clap idices: ^2 ^3 ^4
/// //
/// // clap sees the above as 'myapp -o val1 val2 val3'
/// // ^0 ^1 ^2 ^3 ^4
/// assert_eq!(m.indices_of("option").unwrap().collect::<Vec<_>>(), &[2, 3, 4]);
/// ```
///
/// Another quick example is when flags and options are used together
///
/// ```rust
/// # use clap::{App, Arg};
/// let m = App::new("myapp")
/// .arg(Arg::with_name("option")
/// .short("o")
/// .takes_value(true)
/// .multiple(true))
/// .arg(Arg::with_name("flag")
/// .short("f")
/// .multiple(true))
/// .get_matches_from(vec!["myapp", "-o", "val1", "-f", "-o", "val2", "-f"]);
/// // ARGV idices: ^0 ^1 ^2 ^3 ^4 ^5 ^6
/// // clap idices: ^2 ^3 ^5 ^6
///
/// assert_eq!(m.indices_of("option").unwrap().collect::<Vec<_>>(), &[2, 5]);
/// assert_eq!(m.indices_of("flag").unwrap().collect::<Vec<_>>(), &[3, 6]);
/// ```
/// [`ArgMatches`]: ./struct.ArgMatches.html
/// [`ArgMatches::index_of`]: ./struct.ArgMatches.html#method.index_of
/// [delimiter]: ./struct.Arg.html#method.value_delimiter
pub fn indices_of<S: AsRef<str>>(&self, name: S) -> Option<&str> {
unimplemented!()
}

/// Because [`Subcommand`]s are essentially "sub-[`App`]s" they have their own [`ArgMatches`]
/// as well. This method returns the [`ArgMatches`] for a particular subcommand or `None` if
/// the subcommand wasn't present at runtime.
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