pub struct Parser { /* private fields */ }
Expand description
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::Opt;
// args = ["program", "-abc", "foo"];
let mut opts = getopt::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::Opt;
// args = ["program", "-abc", "-d", "foo", "-e", "bar"];
let mut opts = getopt::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());
Implementations§
source§impl Parser
impl Parser
sourcepub fn new(args: &[String], optstring: &str) -> Self
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 String
s 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).
sourcepub fn index(&self) -> usize
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.
sourcepub fn incr_index(&mut self)
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§
source§impl Iterator for Parser
impl Iterator for Parser
source§fn next(&mut self) -> Option<Result<Opt>>
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()
);
source§fn next_chunk<const N: usize>(
&mut self
) -> Result<[Self::Item; N], IntoIter<Self::Item, N>>where
Self: Sized,
fn next_chunk<const N: usize>(
&mut self
) -> Result<[Self::Item; N], IntoIter<Self::Item, N>>where
Self: Sized,
iter_next_chunk
)N
values. Read more1.0.0 · source§fn size_hint(&self) -> (usize, Option<usize>)
fn size_hint(&self) -> (usize, Option<usize>)
1.0.0 · source§fn count(self) -> usizewhere
Self: Sized,
fn count(self) -> usizewhere
Self: Sized,
1.0.0 · source§fn last(self) -> Option<Self::Item>where
Self: Sized,
fn last(self) -> Option<Self::Item>where
Self: Sized,
source§fn advance_by(&mut self, n: usize) -> Result<(), NonZero<usize>>
fn advance_by(&mut self, n: usize) -> Result<(), NonZero<usize>>
iter_advance_by
)n
elements. Read more1.0.0 · source§fn nth(&mut self, n: usize) -> Option<Self::Item>
fn nth(&mut self, n: usize) -> Option<Self::Item>
n
th element of the iterator. Read more1.28.0 · source§fn step_by(self, step: usize) -> StepBy<Self>where
Self: Sized,
fn step_by(self, step: usize) -> StepBy<Self>where
Self: Sized,
1.0.0 · source§fn chain<U>(self, other: U) -> Chain<Self, <U as IntoIterator>::IntoIter>
fn chain<U>(self, other: U) -> Chain<Self, <U as IntoIterator>::IntoIter>
1.0.0 · source§fn zip<U>(self, other: U) -> Zip<Self, <U as IntoIterator>::IntoIter>where
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U: IntoIterator,
source§fn intersperse_with<G>(self, separator: G) -> IntersperseWith<Self, G>
fn intersperse_with<G>(self, separator: G) -> IntersperseWith<Self, G>
iter_intersperse
)separator
between adjacent items of the original iterator. Read more1.0.0 · source§fn map<B, F>(self, f: F) -> Map<Self, F>
fn map<B, F>(self, f: F) -> Map<Self, F>
1.0.0 · source§fn filter<P>(self, predicate: P) -> Filter<Self, P>
fn filter<P>(self, predicate: P) -> Filter<Self, P>
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fn filter_map<B, F>(self, f: F) -> FilterMap<Self, F>
1.0.0 · source§fn enumerate(self) -> Enumerate<Self>where
Self: Sized,
fn enumerate(self) -> Enumerate<Self>where
Self: Sized,
1.0.0 · source§fn skip_while<P>(self, predicate: P) -> SkipWhile<Self, P>
fn skip_while<P>(self, predicate: P) -> SkipWhile<Self, P>
1.0.0 · source§fn take_while<P>(self, predicate: P) -> TakeWhile<Self, P>
fn take_while<P>(self, predicate: P) -> TakeWhile<Self, P>
1.57.0 · source§fn map_while<B, P>(self, predicate: P) -> MapWhile<Self, P>
fn map_while<B, P>(self, predicate: P) -> MapWhile<Self, P>
1.0.0 · source§fn skip(self, n: usize) -> Skip<Self>where
Self: Sized,
fn skip(self, n: usize) -> Skip<Self>where
Self: Sized,
n
elements. Read more1.0.0 · source§fn take(self, n: usize) -> Take<Self>where
Self: Sized,
fn take(self, n: usize) -> Take<Self>where
Self: Sized,
n
elements, or fewer
if the underlying iterator ends sooner. Read more1.0.0 · source§fn flat_map<U, F>(self, f: F) -> FlatMap<Self, U, F>
fn flat_map<U, F>(self, f: F) -> FlatMap<Self, U, F>
1.29.0 · source§fn flatten(self) -> Flatten<Self>
fn flatten(self) -> Flatten<Self>
source§fn map_windows<F, R, const N: usize>(self, f: F) -> MapWindows<Self, F, N>
fn map_windows<F, R, const N: usize>(self, f: F) -> MapWindows<Self, F, N>
iter_map_windows
)f
for each contiguous window of size N
over
self
and returns an iterator over the outputs of f
. Like slice::windows()
,
the windows during mapping overlap as well. Read more1.0.0 · source§fn inspect<F>(self, f: F) -> Inspect<Self, F>
fn inspect<F>(self, f: F) -> Inspect<Self, F>
1.0.0 · source§fn by_ref(&mut self) -> &mut Selfwhere
Self: Sized,
fn by_ref(&mut self) -> &mut Selfwhere
Self: Sized,
source§fn try_collect<B>(
&mut self
) -> <<Self::Item as Try>::Residual as Residual<B>>::TryType
fn try_collect<B>( &mut self ) -> <<Self::Item as Try>::Residual as Residual<B>>::TryType
iterator_try_collect
)source§fn collect_into<E>(self, collection: &mut E) -> &mut E
fn collect_into<E>(self, collection: &mut E) -> &mut E
iter_collect_into
)1.0.0 · source§fn partition<B, F>(self, f: F) -> (B, B)
fn partition<B, F>(self, f: F) -> (B, B)
source§fn is_partitioned<P>(self, predicate: P) -> bool
fn is_partitioned<P>(self, predicate: P) -> bool
iter_is_partitioned
)true
precede all those that return false
. Read more1.27.0 · source§fn try_fold<B, F, R>(&mut self, init: B, f: F) -> R
fn try_fold<B, F, R>(&mut self, init: B, f: F) -> R
1.27.0 · source§fn try_for_each<F, R>(&mut self, f: F) -> R
fn try_for_each<F, R>(&mut self, f: F) -> R
1.0.0 · source§fn fold<B, F>(self, init: B, f: F) -> B
fn fold<B, F>(self, init: B, f: F) -> B
1.51.0 · source§fn reduce<F>(self, f: F) -> Option<Self::Item>
fn reduce<F>(self, f: F) -> Option<Self::Item>
source§fn try_reduce<F, R>(
&mut self,
f: F
) -> <<R as Try>::Residual as Residual<Option<<R as Try>::Output>>>::TryType
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1.0.0 · source§fn any<F>(&mut self, f: F) -> bool
fn any<F>(&mut self, f: F) -> bool
1.0.0 · source§fn find<P>(&mut self, predicate: P) -> Option<Self::Item>
fn find<P>(&mut self, predicate: P) -> Option<Self::Item>
1.30.0 · source§fn find_map<B, F>(&mut self, f: F) -> Option<B>
fn find_map<B, F>(&mut self, f: F) -> Option<B>
source§fn try_find<F, R>(
&mut self,
f: F
) -> <<R as Try>::Residual as Residual<Option<Self::Item>>>::TryType
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1.6.0 · source§fn max_by_key<B, F>(self, f: F) -> Option<Self::Item>
fn max_by_key<B, F>(self, f: F) -> Option<Self::Item>
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fn max_by<F>(self, compare: F) -> Option<Self::Item>
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fn min_by<F>(self, compare: F) -> Option<Self::Item>
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fn unzip<A, B, FromA, FromB>(self) -> (FromA, FromB)
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fn copied<'a, T>(self) -> Copied<Self>
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)N
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fn product<P>(self) -> P
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fn partial_cmp<I>(self, other: I) -> Option<Ordering>
PartialOrd
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