Struct getopt::Parser

pub struct Parser { /* fields omitted */ }

The core of the getopt crate.

Parser is implemented as an iterator over the options present in the given argument vector.

The method next does the heavy lifting.

Examples

Simplified usage:

use getopt::prelude::*;

// args = ["program", "-abc", "foo"];
let mut opts = Parser::new(&args, "ab:c");

assert_eq!(Some(Opt('a', None)), opts.next().transpose()?);
assert_eq!(1, opts.index());
assert_eq!(Some(Opt('b', Some("c".to_string()))), opts.next().transpose()?);
assert_eq!(2, opts.index());
assert_eq!(None, opts.next());
assert_eq!(2, opts.index());
assert_eq!("foo", args[opts.index()]);

A more idiomatic example:

use getopt::prelude::*;

// args = ["program", "-abc", "-d", "foo", "-e", "bar"];
let mut opts = Parser::new(&args, "ab:cd:e");

let mut a_flag = false;
let mut b_flag = String::new();
let mut c_flag = false;
let mut d_flag = String::new();
let mut e_flag = false;

loop {
    match opts.next().transpose()? {
        None => break,
        Some(opt) => match opt {
            Opt('a', None) => a_flag = true,
            Opt('b', Some(arg)) => b_flag = arg.clone(),
            Opt('c', None) => c_flag = true,
            Opt('d', Some(arg)) => d_flag = arg.clone(),
            Opt('e', None) => e_flag = true,
            _ => unreachable!(),
        },
    }
}

let new_args = args.split_off(opts.index());

assert_eq!(true, a_flag);
assert_eq!("c", b_flag);
assert_eq!(false, c_flag);
assert_eq!("foo", d_flag);
assert_eq!(true, e_flag);

assert_eq!(1, new_args.len());
assert_eq!("bar", new_args.first().unwrap());

Methods

impl Parser

pub fn new(args: &[String], optstring: &str) -> Self

Create a new Parser, which will process the arguments in args according to the options specified in optstring.

For compatibility with std::env::args, valid options are expected to begin at the second element of args, and index is initialised to 1. If args is structured differently, be sure to call set_index before the first invocation of next.

optstring is a string of recognised option characters; if a character is followed by a colon (:), that option takes an argument.

Note:

Transforming the OS-specific argument strings into a vector of Strings is the sole responsibility of the calling program, as it involves some level of potential information loss (which this crate does not presume to handle unilaterally) and error handling (which would complicate the interface).

pub fn index(&self) -> usize

Return the current index of the parser.

args[index] will always point to the the next element of args; when the parser is finished with an element, it will increment index.

After the last option has been parsed (and next is returning None), index will point to the first non-option argument.

pub fn set_index(&mut self, value: usize)

Modify the current index of the parser.

pub fn incr_index(&mut self)

Increment the current index of the parser.

This use case is common enough to warrant its own optimised method.

Trait Implementations

impl Eq for Parser

impl Iterator for Parser

type Item = Result<Opt>

The type of the elements being iterated over.

fn next(&mut self) -> Option<Result<Opt>>

Returns the next option, if any.

Returns an Error if an unexpected option is encountered or if an expected argument is not found.

Parsing stops at the first non-hyphenated argument; or at the first argument matching "-"; or after the first argument matching "--".

When no more options are available, next returns None.

Examples

"-"

use getopt::Parser;

// args = ["program", "-", "-a"];
let mut opts = Parser::new(&args, "a");

assert_eq!(None, opts.next());
assert_eq!("-", args[opts.index()]);

"--"

use getopt::Parser;

// args = ["program", "--", "-a"];
let mut opts = Parser::new(&args, "a");

assert_eq!(None, opts.next());
assert_eq!("-a", args[opts.index()]);

Unexpected option:

use getopt::Parser;

// args = ["program", "-b"];
let mut opts = Parser::new(&args, "a");

assert_eq!(
    "unknown option -- 'b'".to_string(),
    opts.next().unwrap().unwrap_err().to_string()
);

Missing argument:

use getopt::Parser;

// args = ["program", "-a"];
let mut opts = Parser::new(&args, "a:");

assert_eq!(
    "option requires an argument -- 'a'".to_string(),
    opts.next().unwrap().unwrap_err().to_string()
);

default fn size_hint(&self) -> (usize, Option<usize>)

Returns the bounds on the remaining length of the iterator.

default fn count(self) -> usize

Consumes the iterator, counting the number of iterations and returning it.

default fn last(self) -> Option<Self::Item>

Consumes the iterator, returning the last element.

default fn nth(&mut self, n: usize) -> Option<Self::Item>

Returns the nth element of the iterator.

default fn step_by(self, step: usize) -> StepBy<Self>

Creates an iterator starting at the same point, but stepping by the given amount at each iteration.

default fn chain<U>(
    self,
    other: U
) -> Chain<Self, <U as IntoIterator>::IntoIter> where
    U: IntoIterator<Item = Self::Item>, 

Takes two iterators and creates a new iterator over both in sequence.

default fn zip<U>(self, other: U) -> Zip<Self, <U as IntoIterator>::IntoIter> where
    U: IntoIterator, 

'Zips up' two iterators into a single iterator of pairs.

default fn map<B, F>(self, f: F) -> Map<Self, F> where
    F: FnMut(Self::Item) -> B, 

Takes a closure and creates an iterator which calls that closure on each element.

default fn for_each<F>(self, f: F) where
    F: FnMut(Self::Item), 

Calls a closure on each element of an iterator.

default fn filter<P>(self, predicate: P) -> Filter<Self, P> where
    P: FnMut(&Self::Item) -> bool, 

Creates an iterator which uses a closure to determine if an element should be yielded.

default fn filter_map<B, F>(self, f: F) -> FilterMap<Self, F> where
    F: FnMut(Self::Item) -> Option<B>, 

Creates an iterator that both filters and maps.

default fn enumerate(self) -> Enumerate<Self>

Creates an iterator which gives the current iteration count as well as the next value.

default fn peekable(self) -> Peekable<Self>

Creates an iterator which can use peek to look at the next element of the iterator without consuming it.

default fn skip_while<P>(self, predicate: P) -> SkipWhile<Self, P> where
    P: FnMut(&Self::Item) -> bool, 

Creates an iterator that [skip]s elements based on a predicate.

default fn take_while<P>(self, predicate: P) -> TakeWhile<Self, P> where
    P: FnMut(&Self::Item) -> bool, 

Creates an iterator that yields elements based on a predicate.

default fn skip(self, n: usize) -> Skip<Self>

Creates an iterator that skips the first n elements.

default fn take(self, n: usize) -> Take<Self>

Creates an iterator that yields its first n elements.

default fn scan<St, B, F>(self, initial_state: St, f: F) -> Scan<Self, St, F> where
    F: FnMut(&mut St, Self::Item) -> Option<B>, 

An iterator adaptor similar to [fold] that holds internal state and produces a new iterator.

default fn flat_map<U, F>(self, f: F) -> FlatMap<Self, U, F> where
    F: FnMut(Self::Item) -> U,
    U: IntoIterator, 

Creates an iterator that works like map, but flattens nested structure.

default fn flatten(self) -> Flatten<Self> where
    Self::Item: IntoIterator, 

Creates an iterator that flattens nested structure.

default fn fuse(self) -> Fuse<Self>

Creates an iterator which ends after the first [None].

default fn inspect<F>(self, f: F) -> Inspect<Self, F> where
    F: FnMut(&Self::Item), 

Do something with each element of an iterator, passing the value on.

default fn by_ref(&mut self) -> &mut Self

Borrows an iterator, rather than consuming it.

#[must_use = "if you really need to exhaust the iterator, consider `.for_each(drop)` instead"]

default fn collect<B>(self) -> B where
    B: FromIterator<Self::Item>, 

Transforms an iterator into a collection.

default fn partition<B, F>(self, f: F) -> (B, B) where
    B: Default + Extend<Self::Item>,
    F: FnMut(&Self::Item) -> bool, 

Consumes an iterator, creating two collections from it.

default fn try_fold<B, F, R>(&mut self, init: B, f: F) -> R where
    F: FnMut(B, Self::Item) -> R,
    R: Try<Ok = B>, 

An iterator method that applies a function as long as it returns successfully, producing a single, final value.

default fn try_for_each<F, R>(&mut self, f: F) -> R where
    F: FnMut(Self::Item) -> R,
    R: Try<Ok = ()>, 

An iterator method that applies a fallible function to each item in the iterator, stopping at the first error and returning that error.

default fn fold<B, F>(self, init: B, f: F) -> B where
    F: FnMut(B, Self::Item) -> B, 

An iterator method that applies a function, producing a single, final value.

default fn all<F>(&mut self, f: F) -> bool where
    F: FnMut(Self::Item) -> bool, 

Tests if every element of the iterator matches a predicate.

default fn any<F>(&mut self, f: F) -> bool where
    F: FnMut(Self::Item) -> bool, 

Tests if any element of the iterator matches a predicate.

default fn find<P>(&mut self, predicate: P) -> Option<Self::Item> where
    P: FnMut(&Self::Item) -> bool, 

Searches for an element of an iterator that satisfies a predicate.

default fn find_map<B, F>(&mut self, f: F) -> Option<B> where
    F: FnMut(Self::Item) -> Option<B>, 

Applies function to the elements of iterator and returns the first non-none result.

default fn position<P>(&mut self, predicate: P) -> Option<usize> where
    P: FnMut(Self::Item) -> bool, 

Searches for an element in an iterator, returning its index.

default fn rposition<P>(&mut self, predicate: P) -> Option<usize> where
    P: FnMut(Self::Item) -> bool,
    Self: ExactSizeIterator + DoubleEndedIterator, 

Searches for an element in an iterator from the right, returning its index.

default fn max(self) -> Option<Self::Item> where
    Self::Item: Ord, 

Returns the maximum element of an iterator.

default fn min(self) -> Option<Self::Item> where
    Self::Item: Ord, 

Returns the minimum element of an iterator.

default fn max_by_key<B, F>(self, f: F) -> Option<Self::Item> where
    B: Ord,
    F: FnMut(&Self::Item) -> B, 

Returns the element that gives the maximum value from the specified function.

default fn max_by<F>(self, compare: F) -> Option<Self::Item> where
    F: FnMut(&Self::Item, &Self::Item) -> Ordering, 

Returns the element that gives the maximum value with respect to the specified comparison function.

default fn min_by_key<B, F>(self, f: F) -> Option<Self::Item> where
    B: Ord,
    F: FnMut(&Self::Item) -> B, 

Returns the element that gives the minimum value from the specified function.

default fn min_by<F>(self, compare: F) -> Option<Self::Item> where
    F: FnMut(&Self::Item, &Self::Item) -> Ordering, 

Returns the element that gives the minimum value with respect to the specified comparison function.

default fn rev(self) -> Rev<Self> where
    Self: DoubleEndedIterator, 

Reverses an iterator's direction.

default fn unzip<A, B, FromA, FromB>(self) -> (FromA, FromB) where
    FromA: Default + Extend<A>,
    FromB: Default + Extend<B>,
    Self: Iterator<Item = (A, B)>, 

Converts an iterator of pairs into a pair of containers.

default fn copied<'a, T>(self) -> Copied<Self> where
    Self: Iterator<Item = &'a T>,
    T: 'a + Copy, 

🔬 This is a nightly-only experimental API. (iter_copied)

Creates an iterator which copies all of its elements.

default fn cloned<'a, T>(self) -> Cloned<Self> where
    Self: Iterator<Item = &'a T>,
    T: 'a + Clone, 

Creates an iterator which [clone]s all of its elements.

default fn cycle(self) -> Cycle<Self> where
    Self: Clone, 

Repeats an iterator endlessly.

default fn sum<S>(self) -> S where
    S: Sum<Self::Item>, 

Sums the elements of an iterator.

default fn product<P>(self) -> P where
    P: Product<Self::Item>, 

Iterates over the entire iterator, multiplying all the elements

default fn cmp<I>(self, other: I) -> Ordering where
    I: IntoIterator<Item = Self::Item>,
    Self::Item: Ord, 

Lexicographically compares the elements of this Iterator with those of another.

default fn partial_cmp<I>(self, other: I) -> Option<Ordering> where
    I: IntoIterator,
    Self::Item: PartialOrd<<I as IntoIterator>::Item>, 

Lexicographically compares the elements of this Iterator with those of another.

default fn eq<I>(self, other: I) -> bool where
    I: IntoIterator,
    Self::Item: PartialEq<<I as IntoIterator>::Item>, 

Determines if the elements of this Iterator are equal to those of another.

default fn ne<I>(self, other: I) -> bool where
    I: IntoIterator,
    Self::Item: PartialEq<<I as IntoIterator>::Item>, 

Determines if the elements of this Iterator are unequal to those of another.

default fn lt<I>(self, other: I) -> bool where
    I: IntoIterator,
    Self::Item: PartialOrd<<I as IntoIterator>::Item>, 

Determines if the elements of this Iterator are lexicographically less than those of another.

default fn le<I>(self, other: I) -> bool where
    I: IntoIterator,
    Self::Item: PartialOrd<<I as IntoIterator>::Item>, 

Determines if the elements of this Iterator are lexicographically less or equal to those of another.

default fn gt<I>(self, other: I) -> bool where
    I: IntoIterator,
    Self::Item: PartialOrd<<I as IntoIterator>::Item>, 

Determines if the elements of this Iterator are lexicographically greater than those of another.

default fn ge<I>(self, other: I) -> bool where
    I: IntoIterator,
    Self::Item: PartialOrd<<I as IntoIterator>::Item>, 

Determines if the elements of this Iterator are lexicographically greater than or equal to those of another.

default fn is_sorted(self) -> bool where
    Self::Item: PartialOrd<Self::Item>, 

🔬 This is a nightly-only experimental API. (is_sorted)

new API

Checks if the elements of this iterator are sorted.

default fn is_sorted_by<F>(self, compare: F) -> bool where
    F: FnMut(&Self::Item, &Self::Item) -> Option<Ordering>, 

🔬 This is a nightly-only experimental API. (is_sorted)

new API

Checks if the elements of this iterator are sorted using the given comparator function.

default fn is_sorted_by_key<F, K>(self, f: F) -> bool where
    F: FnMut(&Self::Item) -> K,
    K: PartialOrd<K>, 

🔬 This is a nightly-only experimental API. (is_sorted)

new API

Checks if the elements of this iterator are sorted using the given key extraction function.

impl PartialEq<Parser> for Parser

fn eq(&self, other: &Parser) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Parser) -> bool

This method tests for !=.

impl Debug for Parser

fn fmt(&self, f: &mut Formatter) -> Result

Formats the value using the given formatter.