Struct FlagSet

Source

pub struct FlagSet<'a> { /* private fields */ }

Expand description

A set of flags. Allows fine control over parse procedure.

Typically you can use the parse function.

§Example

let mut force = false;
let mut lines = 10_i32;
let args: Vec<String>;
{
    let mut flags = FlagSet::new();
    flags.add_flag("f", &mut force);
    flags.add_flag("lines", &mut lines);
    args = flags.parse(&["-f", "--lines", "20", "--", "foo"])?;
}
assert_eq!(force, true);
assert_eq!(lines, 20);
assert_eq!(args, vec![String::from("foo")]);

Implementations§

Source §

impl<'a> FlagSet<'a>

Source

pub fn new() -> Self

Creates a new set of flags.

§Example

let mut flags = FlagSet::new();

Source

pub fn add_flag(&mut self, name: &'a str, value: &'a mut dyn FlagSetter)

Add a flag to be parsed.

§Panics

Panics if the flag of the same name is already registered.

§Example

let mut force = false;
let mut flags = FlagSet::new();
flags.add_flag("f", &mut force);

Examples found in repository ?

examples/someflags.rs (line 7)

3fn main() {
4    let mut force = false;
5    let mut lines = 10_i32;
6    let args: Vec<OsString> = go_flag::parse(|flags| {
7        flags.add_flag("f", &mut force);
8        flags.add_flag("lines", &mut lines);
9    });
10    println!("force = {:?}", force);
11    println!("lines = {:?}", lines);
12    for arg in &args {
13        println!("{}", arg.to_string_lossy());
14    }
15}

Source

pub fn parse<'b, T: FlagValue, S: AsRef<OsStr>>( &mut self, args: &'b [S], ) -> Result<Vec<T>, FlagError>

Parses the given arguments.

§Returns

Returns the list of positional arguments (remaining arguments).

Positional arguments can also be parsed. You’ll typically need Vec<String>, Vec<OsString> or Vec<PathBuf>.

§Errors

It returns Err if the given arguments contains invalid flags.

§Example

let mut force = false;
let mut flags = FlagSet::new();
flags.add_flag("f", &mut force);
let args: Vec<String> = flags.parse(&["-f", "foo"])?;
assert_eq!(args, vec![String::from("foo")]);

Source

pub fn parse_with_warnings<'b, T: FlagValue, S: AsRef<OsStr>>( &mut self, args: &'b [S], warnings: Option<&mut Vec<FlagWarning>>, ) -> Result<Vec<T>, FlagError>

Parses the given arguments, recording warnings issued.

§Returns

Returns the list of positional arguments (remaining arguments).

Positional arguments can also be parsed. You’ll typically need Vec<String>, Vec<OsString> or Vec<PathBuf>.

§Errors

It returns Err if the given arguments contains invalid flags.

§Example

let mut warnings = Vec::new();
let mut force = false;
let mut flags = FlagSet::new();
flags.add_flag("f", &mut force);
let args: Vec<String> = flags
    .parse_with_warnings(&["--f", "foo", "-non-flag"], Some(&mut warnings))?;
assert_eq!(args, vec![String::from("foo"), String::from("-non-flag")]);
assert_eq!(warnings[0].to_string(), "short flag with double minuses: --f");
assert_eq!(warnings[1].to_string(), "flag-like syntax appearing after argument: -non-flag");