Simple getopt alternative.
Construct a vector of options, either by using reqopt, optopt, and optflag or by building them from components yourself, and pass them to getopts, along with a vector of actual arguments (not including argv[0]). You'll either get a failure code back, or a match. You'll have to verify whether the amount of 'free' arguments in the match is what you expect. Use opt_* accessors to get argument values out of the matches object.
Single-character options are expected to appear on the command line with a single preceding dash; multiple-character options are expected to be proceeded by two dashes. Options that expect an argument accept their argument following either a space or an equals sign. Single-character options don't require the space.
The following example shows simple command line parsing for an application that requires an input file to be specified, accepts an optional output file name following -o, and accepts both -h and --help as optional flags.
exter mod extra;
use extra::getopts::*;
use std::os;
fn do_work(inp: &str, out: Option<~str>) {
println(inp);
println(match out {
Some(x) => x,
None => ~"No Output"
});
}
fn print_usage(program: &str, _opts: &[Opt]) {
printfln!("Usage: %s [options]", program);
println("-o\t\tOutput");
println("-h --help\tUsage");
}
fn main() {
let args = os::args();
let program = args[0].clone();
let opts = ~[
optopt("o"),
optflag("h"),
optflag("help")
];
let matches = match getopts(args.tail(), opts) {
Ok(m) => { m }
Err(f) => { fail!(f.to_err_msg()) }
};
if matches.opt_present("h") || matches.opt_present("help") {
print_usage(program, opts);
return;
}
let output = matches.opt_str("o");
let input: &str = if !matches.free.is_empty() {
matches.free[0].clone()
} else {
print_usage(program, opts);
return;
};
do_work(input, output);
}
groups | A module which provides a way to specify descriptions and groups of short and long option names, together. |
Matches | The result of checking command line arguments. Contains a vector of matches and a vector of free strings. |
Opt | A description of a possible option. |
FailType | The type of failure that occured. |
Fail_ | The type returned when the command line does not conform to the
expected format. Pass this value to |
HasArg | Describes whether an option has an argument. |
Name | Name of an option. Either a string or a single char. |
Occur | Describes how often an option may occur. |
getopts | Parse command line arguments according to the provided options. |
optflag | Create an option that is optional and does not take an argument. |
optflagmulti | Create an option that is optional, does not take an argument, and may occur multiple times. |
optflagopt | Create an option that is optional and takes an optional argument. |
optmulti | Create an option that is optional, takes an argument, and may occur multiple times. |
optopt | Create an option that is optional and takes an argument. |
reqopt | Create an option that is required and takes an argument. |
Result | The result of parsing a command line with a set of options. |
Prefix searches with a type followed by a colon (e.g.
fn:
) to restrict the search to a given type.
Accepted types are: fn
, mod
,
struct
(or str
), enum
,
trait
, typedef
(or
tdef
).