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//! Combinators applying their child parser multiple times
#[cfg(test)]
mod tests;
use crate::error::ErrorKind;
use crate::error::ParseError;
use crate::internal::{Err, IResult, Needed, Parser};
#[cfg(feature = "alloc")]
use crate::lib::std::vec::Vec;
use crate::traits::{InputLength, InputTake, ToUsize};
use core::num::NonZeroUsize;
/// Don't pre-allocate more than 64KiB when calling `Vec::with_capacity`.
///
/// Pre-allocating memory is a nice optimization but count fields can't
/// always be trusted. We should clamp initial capacities to some reasonable
/// amount. This reduces the risk of a bogus count value triggering a panic
/// due to an OOM error.
///
/// This does not affect correctness. Nom will always read the full number
/// of elements regardless of the capacity cap.
#[cfg(feature = "alloc")]
const MAX_INITIAL_CAPACITY_BYTES: usize = 65536;
/// Repeats the embedded parser, gathering the results in a `Vec`.
///
/// This stops on [`Err::Error`] and returns the results that were accumulated. To instead chain an error up, see
/// [`cut`][crate::combinator::cut].
///
/// # Arguments
/// * `f` The parser to apply.
///
/// *Note*: if the parser passed in accepts empty inputs (like `alpha0` or `digit0`), `many0` will
/// return an error, to prevent going into an infinite loop
///
/// ```rust
/// # use nom::{Err, error::ErrorKind, Needed, IResult};
/// use nom::multi::many0;
/// use nom::bytes::complete::tag;
///
/// fn parser(s: &str) -> IResult<&str, Vec<&str>> {
/// many0(tag("abc"))(s)
/// }
///
/// assert_eq!(parser("abcabc"), Ok(("", vec!["abc", "abc"])));
/// assert_eq!(parser("abc123"), Ok(("123", vec!["abc"])));
/// assert_eq!(parser("123123"), Ok(("123123", vec![])));
/// assert_eq!(parser(""), Ok(("", vec![])));
/// ```
#[cfg(feature = "alloc")]
#[cfg_attr(feature = "docsrs", doc(cfg(feature = "alloc")))]
pub fn many0<I, O, E, F>(mut f: F) -> impl FnMut(I) -> IResult<I, Vec<O>, E>
where
I: Clone + InputLength,
F: Parser<I, O, E>,
E: ParseError<I>,
{
move |mut i: I| {
let mut acc = crate::lib::std::vec::Vec::with_capacity(4);
loop {
let len = i.input_len();
match f.parse(i.clone()) {
Err(Err::Error(_)) => return Ok((i, acc)),
Err(e) => return Err(e),
Ok((i1, o)) => {
// infinite loop check: the parser must always consume
if i1.input_len() == len {
return Err(Err::Error(E::from_error_kind(i, ErrorKind::Many0)));
}
i = i1;
acc.push(o);
}
}
}
}
}
/// Runs the embedded parser, gathering the results in a `Vec`.
///
/// This stops on [`Err::Error`] if there is at least one result, and returns the results that were accumulated. To instead chain an error up,
/// see [`cut`][crate::combinator::cut].
///
/// # Arguments
/// * `f` The parser to apply.
///
/// *Note*: If the parser passed to `many1` accepts empty inputs
/// (like `alpha0` or `digit0`), `many1` will return an error,
/// to prevent going into an infinite loop.
///
/// ```rust
/// # use nom::{Err, error::{Error, ErrorKind}, Needed, IResult};
/// use nom::multi::many1;
/// use nom::bytes::complete::tag;
///
/// fn parser(s: &str) -> IResult<&str, Vec<&str>> {
/// many1(tag("abc"))(s)
/// }
///
/// assert_eq!(parser("abcabc"), Ok(("", vec!["abc", "abc"])));
/// assert_eq!(parser("abc123"), Ok(("123", vec!["abc"])));
/// assert_eq!(parser("123123"), Err(Err::Error(Error::new("123123", ErrorKind::Tag))));
/// assert_eq!(parser(""), Err(Err::Error(Error::new("", ErrorKind::Tag))));
/// ```
#[cfg(feature = "alloc")]
#[cfg_attr(feature = "docsrs", doc(cfg(feature = "alloc")))]
pub fn many1<I, O, E, F>(mut f: F) -> impl FnMut(I) -> IResult<I, Vec<O>, E>
where
I: Clone + InputLength,
F: Parser<I, O, E>,
E: ParseError<I>,
{
move |mut i: I| match f.parse(i.clone()) {
Err(Err::Error(err)) => Err(Err::Error(E::append(i, ErrorKind::Many1, err))),
Err(e) => Err(e),
Ok((i1, o)) => {
let mut acc = crate::lib::std::vec::Vec::with_capacity(4);
acc.push(o);
i = i1;
loop {
let len = i.input_len();
match f.parse(i.clone()) {
Err(Err::Error(_)) => return Ok((i, acc)),
Err(e) => return Err(e),
Ok((i1, o)) => {
// infinite loop check: the parser must always consume
if i1.input_len() == len {
return Err(Err::Error(E::from_error_kind(i, ErrorKind::Many1)));
}
i = i1;
acc.push(o);
}
}
}
}
}
}
/// Applies the parser `f` until the parser `g` produces a result.
///
/// Returns a tuple of the results of `f` in a `Vec` and the result of `g`.
///
/// `f` keeps going so long as `g` produces [`Err::Error`]. To instead chain an error up, see [`cut`][crate::combinator::cut].
///
/// ```rust
/// # use nom::{Err, error::{Error, ErrorKind}, Needed, IResult};
/// use nom::multi::many_till;
/// use nom::bytes::complete::tag;
///
/// fn parser(s: &str) -> IResult<&str, (Vec<&str>, &str)> {
/// many_till(tag("abc"), tag("end"))(s)
/// };
///
/// assert_eq!(parser("abcabcend"), Ok(("", (vec!["abc", "abc"], "end"))));
/// assert_eq!(parser("abc123end"), Err(Err::Error(Error::new("123end", ErrorKind::Tag))));
/// assert_eq!(parser("123123end"), Err(Err::Error(Error::new("123123end", ErrorKind::Tag))));
/// assert_eq!(parser(""), Err(Err::Error(Error::new("", ErrorKind::Tag))));
/// assert_eq!(parser("abcendefg"), Ok(("efg", (vec!["abc"], "end"))));
/// ```
#[cfg(feature = "alloc")]
#[cfg_attr(feature = "docsrs", doc(cfg(feature = "alloc")))]
pub fn many_till<I, O, P, E, F, G>(
mut f: F,
mut g: G,
) -> impl FnMut(I) -> IResult<I, (Vec<O>, P), E>
where
I: Clone + InputLength,
F: Parser<I, O, E>,
G: Parser<I, P, E>,
E: ParseError<I>,
{
move |mut i: I| {
let mut res = crate::lib::std::vec::Vec::new();
loop {
let len = i.input_len();
match g.parse(i.clone()) {
Ok((i1, o)) => return Ok((i1, (res, o))),
Err(Err::Error(_)) => {
match f.parse(i.clone()) {
Err(Err::Error(err)) => return Err(Err::Error(E::append(i, ErrorKind::ManyTill, err))),
Err(e) => return Err(e),
Ok((i1, o)) => {
// infinite loop check: the parser must always consume
if i1.input_len() == len {
return Err(Err::Error(E::from_error_kind(i1, ErrorKind::ManyTill)));
}
res.push(o);
i = i1;
}
}
}
Err(e) => return Err(e),
}
}
}
}
/// Alternates between two parsers to produce a list of elements.
///
/// This stops when either parser returns [`Err::Error`] and returns the results that were accumulated. To instead chain an error up, see
/// [`cut`][crate::combinator::cut].
///
/// # Arguments
/// * `sep` Parses the separator between list elements.
/// * `f` Parses the elements of the list.
///
/// ```rust
/// # use nom::{Err, error::ErrorKind, Needed, IResult};
/// use nom::multi::separated_list0;
/// use nom::bytes::complete::tag;
///
/// fn parser(s: &str) -> IResult<&str, Vec<&str>> {
/// separated_list0(tag("|"), tag("abc"))(s)
/// }
///
/// assert_eq!(parser("abc|abc|abc"), Ok(("", vec!["abc", "abc", "abc"])));
/// assert_eq!(parser("abc123abc"), Ok(("123abc", vec!["abc"])));
/// assert_eq!(parser("abc|def"), Ok(("|def", vec!["abc"])));
/// assert_eq!(parser(""), Ok(("", vec![])));
/// assert_eq!(parser("def|abc"), Ok(("def|abc", vec![])));
/// ```
#[cfg(feature = "alloc")]
#[cfg_attr(feature = "docsrs", doc(cfg(feature = "alloc")))]
pub fn separated_list0<I, O, O2, E, F, G>(
mut sep: G,
mut f: F,
) -> impl FnMut(I) -> IResult<I, Vec<O>, E>
where
I: Clone + InputLength,
F: Parser<I, O, E>,
G: Parser<I, O2, E>,
E: ParseError<I>,
{
move |mut i: I| {
let mut res = Vec::new();
match f.parse(i.clone()) {
Err(Err::Error(_)) => return Ok((i, res)),
Err(e) => return Err(e),
Ok((i1, o)) => {
res.push(o);
i = i1;
}
}
loop {
let len = i.input_len();
match sep.parse(i.clone()) {
Err(Err::Error(_)) => return Ok((i, res)),
Err(e) => return Err(e),
Ok((i1, _)) => {
// infinite loop check: the parser must always consume
if i1.input_len() == len {
return Err(Err::Error(E::from_error_kind(i1, ErrorKind::SeparatedList)));
}
match f.parse(i1.clone()) {
Err(Err::Error(_)) => return Ok((i, res)),
Err(e) => return Err(e),
Ok((i2, o)) => {
res.push(o);
i = i2;
}
}
}
}
}
}
}
/// Alternates between two parsers to produce a list of elements until [`Err::Error`].
///
/// Fails if the element parser does not produce at least one element.$
///
/// This stops when either parser returns [`Err::Error`] and returns the results that were accumulated. To instead chain an error up, see
/// [`cut`][crate::combinator::cut].
///
/// # Arguments
/// * `sep` Parses the separator between list elements.
/// * `f` Parses the elements of the list.
/// ```rust
/// # use nom::{Err, error::{Error, ErrorKind}, Needed, IResult};
/// use nom::multi::separated_list1;
/// use nom::bytes::complete::tag;
///
/// fn parser(s: &str) -> IResult<&str, Vec<&str>> {
/// separated_list1(tag("|"), tag("abc"))(s)
/// }
///
/// assert_eq!(parser("abc|abc|abc"), Ok(("", vec!["abc", "abc", "abc"])));
/// assert_eq!(parser("abc123abc"), Ok(("123abc", vec!["abc"])));
/// assert_eq!(parser("abc|def"), Ok(("|def", vec!["abc"])));
/// assert_eq!(parser(""), Err(Err::Error(Error::new("", ErrorKind::Tag))));
/// assert_eq!(parser("def|abc"), Err(Err::Error(Error::new("def|abc", ErrorKind::Tag))));
/// ```
#[cfg(feature = "alloc")]
#[cfg_attr(feature = "docsrs", doc(cfg(feature = "alloc")))]
pub fn separated_list1<I, O, O2, E, F, G>(
mut sep: G,
mut f: F,
) -> impl FnMut(I) -> IResult<I, Vec<O>, E>
where
I: Clone + InputLength,
F: Parser<I, O, E>,
G: Parser<I, O2, E>,
E: ParseError<I>,
{
move |mut i: I| {
let mut res = Vec::new();
// Parse the first element
match f.parse(i.clone()) {
Err(e) => return Err(e),
Ok((i1, o)) => {
res.push(o);
i = i1;
}
}
loop {
let len = i.input_len();
match sep.parse(i.clone()) {
Err(Err::Error(_)) => return Ok((i, res)),
Err(e) => return Err(e),
Ok((i1, _)) => {
// infinite loop check: the parser must always consume
if i1.input_len() == len {
return Err(Err::Error(E::from_error_kind(i1, ErrorKind::SeparatedList)));
}
match f.parse(i1.clone()) {
Err(Err::Error(_)) => return Ok((i, res)),
Err(e) => return Err(e),
Ok((i2, o)) => {
res.push(o);
i = i2;
}
}
}
}
}
}
}
/// Repeats the embedded parser `m..=n` times
///
/// This stops before `n` when the parser returns [`Err::Error`] and returns the results that were accumulated. To instead chain an error up, see
/// [`cut`][crate::combinator::cut].
///
/// # Arguments
/// * `m` The minimum number of iterations.
/// * `n` The maximum number of iterations.
/// * `f` The parser to apply.
///
/// *Note*: If the parser passed to `many1` accepts empty inputs
/// (like `alpha0` or `digit0`), `many1` will return an error,
/// to prevent going into an infinite loop.
///
/// ```rust
/// # use nom::{Err, error::ErrorKind, Needed, IResult};
/// use nom::multi::many_m_n;
/// use nom::bytes::complete::tag;
///
/// fn parser(s: &str) -> IResult<&str, Vec<&str>> {
/// many_m_n(0, 2, tag("abc"))(s)
/// }
///
/// assert_eq!(parser("abcabc"), Ok(("", vec!["abc", "abc"])));
/// assert_eq!(parser("abc123"), Ok(("123", vec!["abc"])));
/// assert_eq!(parser("123123"), Ok(("123123", vec![])));
/// assert_eq!(parser(""), Ok(("", vec![])));
/// assert_eq!(parser("abcabcabc"), Ok(("abc", vec!["abc", "abc"])));
/// ```
#[cfg(feature = "alloc")]
#[cfg_attr(feature = "docsrs", doc(cfg(feature = "alloc")))]
pub fn many_m_n<I, O, E, F>(
min: usize,
max: usize,
mut parse: F,
) -> impl FnMut(I) -> IResult<I, Vec<O>, E>
where
I: Clone + InputLength,
F: Parser<I, O, E>,
E: ParseError<I>,
{
move |mut input: I| {
if min > max {
return Err(Err::Failure(E::from_error_kind(input, ErrorKind::ManyMN)));
}
let max_initial_capacity =
MAX_INITIAL_CAPACITY_BYTES / crate::lib::std::mem::size_of::<O>().max(1);
let mut res = crate::lib::std::vec::Vec::with_capacity(min.min(max_initial_capacity));
for count in 0..max {
let len = input.input_len();
match parse.parse(input.clone()) {
Ok((tail, value)) => {
// infinite loop check: the parser must always consume
if tail.input_len() == len {
return Err(Err::Error(E::from_error_kind(input, ErrorKind::ManyMN)));
}
res.push(value);
input = tail;
}
Err(Err::Error(e)) => {
if count < min {
return Err(Err::Error(E::append(input, ErrorKind::ManyMN, e)));
} else {
return Ok((input, res));
}
}
Err(e) => {
return Err(e);
}
}
}
Ok((input, res))
}
}
/// Repeats the embedded parser, counting the results
///
/// This stops on [`Err::Error`]. To instead chain an error up, see
/// [`cut`][crate::combinator::cut].
///
/// # Arguments
/// * `f` The parser to apply.
///
/// *Note*: if the parser passed in accepts empty inputs (like `alpha0` or `digit0`), `many0` will
/// return an error, to prevent going into an infinite loop
///
/// ```rust
/// # use nom::{Err, error::ErrorKind, Needed, IResult};
/// use nom::multi::many0_count;
/// use nom::bytes::complete::tag;
///
/// fn parser(s: &str) -> IResult<&str, usize> {
/// many0_count(tag("abc"))(s)
/// }
///
/// assert_eq!(parser("abcabc"), Ok(("", 2)));
/// assert_eq!(parser("abc123"), Ok(("123", 1)));
/// assert_eq!(parser("123123"), Ok(("123123", 0)));
/// assert_eq!(parser(""), Ok(("", 0)));
/// ```
pub fn many0_count<I, O, E, F>(mut f: F) -> impl FnMut(I) -> IResult<I, usize, E>
where
I: Clone + InputLength,
F: Parser<I, O, E>,
E: ParseError<I>,
{
move |i: I| {
let mut input = i;
let mut count = 0;
loop {
let input_ = input.clone();
let len = input.input_len();
match f.parse(input_) {
Ok((i, _)) => {
// infinite loop check: the parser must always consume
if i.input_len() == len {
return Err(Err::Error(E::from_error_kind(input, ErrorKind::Many0Count)));
}
input = i;
count += 1;
}
Err(Err::Error(_)) => return Ok((input, count)),
Err(e) => return Err(e),
}
}
}
}
/// Runs the embedded parser, counting the results.
///
/// This stops on [`Err::Error`] if there is at least one result. To instead chain an error up,
/// see [`cut`][crate::combinator::cut].
///
/// # Arguments
/// * `f` The parser to apply.
///
/// *Note*: If the parser passed to `many1` accepts empty inputs
/// (like `alpha0` or `digit0`), `many1` will return an error,
/// to prevent going into an infinite loop.
///
/// ```rust
/// # use nom::{Err, error::{Error, ErrorKind}, Needed, IResult};
/// use nom::multi::many1_count;
/// use nom::bytes::complete::tag;
///
/// fn parser(s: &str) -> IResult<&str, usize> {
/// many1_count(tag("abc"))(s)
/// }
///
/// assert_eq!(parser("abcabc"), Ok(("", 2)));
/// assert_eq!(parser("abc123"), Ok(("123", 1)));
/// assert_eq!(parser("123123"), Err(Err::Error(Error::new("123123", ErrorKind::Many1Count))));
/// assert_eq!(parser(""), Err(Err::Error(Error::new("", ErrorKind::Many1Count))));
/// ```
pub fn many1_count<I, O, E, F>(mut f: F) -> impl FnMut(I) -> IResult<I, usize, E>
where
I: Clone + InputLength,
F: Parser<I, O, E>,
E: ParseError<I>,
{
move |i: I| {
let i_ = i.clone();
match f.parse(i_) {
Err(Err::Error(_)) => Err(Err::Error(E::from_error_kind(i, ErrorKind::Many1Count))),
Err(i) => Err(i),
Ok((i1, _)) => {
let mut count = 1;
let mut input = i1;
loop {
let len = input.input_len();
let input_ = input.clone();
match f.parse(input_) {
Err(Err::Error(_)) => return Ok((input, count)),
Err(e) => return Err(e),
Ok((i, _)) => {
// infinite loop check: the parser must always consume
if i.input_len() == len {
return Err(Err::Error(E::from_error_kind(i, ErrorKind::Many1Count)));
}
count += 1;
input = i;
}
}
}
}
}
}
}
/// Runs the embedded parser `count` times, gathering the results in a `Vec`
///
/// # Arguments
/// * `f` The parser to apply.
/// * `count` How often to apply the parser.
/// ```rust
/// # use nom::{Err, error::{Error, ErrorKind}, Needed, IResult};
/// use nom::multi::count;
/// use nom::bytes::complete::tag;
///
/// fn parser(s: &str) -> IResult<&str, Vec<&str>> {
/// count(tag("abc"), 2)(s)
/// }
///
/// assert_eq!(parser("abcabc"), Ok(("", vec!["abc", "abc"])));
/// assert_eq!(parser("abc123"), Err(Err::Error(Error::new("123", ErrorKind::Tag))));
/// assert_eq!(parser("123123"), Err(Err::Error(Error::new("123123", ErrorKind::Tag))));
/// assert_eq!(parser(""), Err(Err::Error(Error::new("", ErrorKind::Tag))));
/// assert_eq!(parser("abcabcabc"), Ok(("abc", vec!["abc", "abc"])));
/// ```
#[cfg(feature = "alloc")]
#[cfg_attr(feature = "docsrs", doc(cfg(feature = "alloc")))]
pub fn count<I, O, E, F>(mut f: F, count: usize) -> impl FnMut(I) -> IResult<I, Vec<O>, E>
where
I: Clone + PartialEq,
F: Parser<I, O, E>,
E: ParseError<I>,
{
move |i: I| {
let mut input = i.clone();
let max_initial_capacity =
MAX_INITIAL_CAPACITY_BYTES / crate::lib::std::mem::size_of::<O>().max(1);
let mut res = crate::lib::std::vec::Vec::with_capacity(count.min(max_initial_capacity));
for _ in 0..count {
let input_ = input.clone();
match f.parse(input_) {
Ok((i, o)) => {
res.push(o);
input = i;
}
Err(Err::Error(e)) => {
return Err(Err::Error(E::append(i, ErrorKind::Count, e)));
}
Err(e) => {
return Err(e);
}
}
}
Ok((input, res))
}
}
/// Runs the embedded parser repeatedly, filling the given slice with results.
///
/// This parser fails if the input runs out before the given slice is full.
///
/// # Arguments
/// * `f` The parser to apply.
/// * `buf` The slice to fill
/// ```rust
/// # use nom::{Err, error::{Error, ErrorKind}, Needed, IResult};
/// use nom::multi::fill;
/// use nom::bytes::complete::tag;
///
/// fn parser(s: &str) -> IResult<&str, [&str; 2]> {
/// let mut buf = ["", ""];
/// let (rest, ()) = fill(tag("abc"), &mut buf)(s)?;
/// Ok((rest, buf))
/// }
///
/// assert_eq!(parser("abcabc"), Ok(("", ["abc", "abc"])));
/// assert_eq!(parser("abc123"), Err(Err::Error(Error::new("123", ErrorKind::Tag))));
/// assert_eq!(parser("123123"), Err(Err::Error(Error::new("123123", ErrorKind::Tag))));
/// assert_eq!(parser(""), Err(Err::Error(Error::new("", ErrorKind::Tag))));
/// assert_eq!(parser("abcabcabc"), Ok(("abc", ["abc", "abc"])));
/// ```
pub fn fill<'a, I, O, E, F>(f: F, buf: &'a mut [O]) -> impl FnMut(I) -> IResult<I, (), E> + 'a
where
I: Clone + PartialEq,
F: Fn(I) -> IResult<I, O, E> + 'a,
E: ParseError<I>,
{
move |i: I| {
let mut input = i.clone();
for elem in buf.iter_mut() {
let input_ = input.clone();
match f(input_) {
Ok((i, o)) => {
*elem = o;
input = i;
}
Err(Err::Error(e)) => {
return Err(Err::Error(E::append(i, ErrorKind::Count, e)));
}
Err(e) => {
return Err(e);
}
}
}
Ok((input, ()))
}
}
/// Repeats the embedded parser, calling `g` to gather the results.
///
/// This stops on [`Err::Error`]. To instead chain an error up, see
/// [`cut`][crate::combinator::cut].
///
/// # Arguments
/// * `f` The parser to apply.
/// * `init` A function returning the initial value.
/// * `g` The function that combines a result of `f` with
/// the current accumulator.
///
/// *Note*: if the parser passed in accepts empty inputs (like `alpha0` or `digit0`), `many0` will
/// return an error, to prevent going into an infinite loop
///
/// ```rust
/// # use nom::{Err, error::ErrorKind, Needed, IResult};
/// use nom::multi::fold_many0;
/// use nom::bytes::complete::tag;
///
/// fn parser(s: &str) -> IResult<&str, Vec<&str>> {
/// fold_many0(
/// tag("abc"),
/// Vec::new,
/// |mut acc: Vec<_>, item| {
/// acc.push(item);
/// acc
/// }
/// )(s)
/// }
///
/// assert_eq!(parser("abcabc"), Ok(("", vec!["abc", "abc"])));
/// assert_eq!(parser("abc123"), Ok(("123", vec!["abc"])));
/// assert_eq!(parser("123123"), Ok(("123123", vec![])));
/// assert_eq!(parser(""), Ok(("", vec![])));
/// ```
pub fn fold_many0<I, O, E, F, G, H, R>(
mut f: F,
mut init: H,
mut g: G,
) -> impl FnMut(I) -> IResult<I, R, E>
where
I: Clone + InputLength,
F: Parser<I, O, E>,
G: FnMut(R, O) -> R,
H: FnMut() -> R,
E: ParseError<I>,
{
move |i: I| {
let mut res = init();
let mut input = i;
loop {
let i_ = input.clone();
let len = input.input_len();
match f.parse(i_) {
Ok((i, o)) => {
// infinite loop check: the parser must always consume
if i.input_len() == len {
return Err(Err::Error(E::from_error_kind(input, ErrorKind::Many0)));
}
res = g(res, o);
input = i;
}
Err(Err::Error(_)) => {
return Ok((input, res));
}
Err(e) => {
return Err(e);
}
}
}
}
}
/// Repeats the embedded parser, calling `g` to gather the results.
///
/// This stops on [`Err::Error`] if there is at least one result. To instead chain an error up,
/// see [`cut`][crate::combinator::cut].
///
/// # Arguments
/// * `f` The parser to apply.
/// * `init` A function returning the initial value.
/// * `g` The function that combines a result of `f` with
/// the current accumulator.
///
/// *Note*: If the parser passed to `many1` accepts empty inputs
/// (like `alpha0` or `digit0`), `many1` will return an error,
/// to prevent going into an infinite loop.
///
/// ```rust
/// # use nom::{Err, error::{Error, ErrorKind}, Needed, IResult};
/// use nom::multi::fold_many1;
/// use nom::bytes::complete::tag;
///
/// fn parser(s: &str) -> IResult<&str, Vec<&str>> {
/// fold_many1(
/// tag("abc"),
/// Vec::new,
/// |mut acc: Vec<_>, item| {
/// acc.push(item);
/// acc
/// }
/// )(s)
/// }
///
/// assert_eq!(parser("abcabc"), Ok(("", vec!["abc", "abc"])));
/// assert_eq!(parser("abc123"), Ok(("123", vec!["abc"])));
/// assert_eq!(parser("123123"), Err(Err::Error(Error::new("123123", ErrorKind::Many1))));
/// assert_eq!(parser(""), Err(Err::Error(Error::new("", ErrorKind::Many1))));
/// ```
pub fn fold_many1<I, O, E, F, G, H, R>(
mut f: F,
mut init: H,
mut g: G,
) -> impl FnMut(I) -> IResult<I, R, E>
where
I: Clone + InputLength,
F: Parser<I, O, E>,
G: FnMut(R, O) -> R,
H: FnMut() -> R,
E: ParseError<I>,
{
move |i: I| {
let _i = i.clone();
let init = init();
match f.parse(_i) {
Err(Err::Error(_)) => Err(Err::Error(E::from_error_kind(i, ErrorKind::Many1))),
Err(e) => Err(e),
Ok((i1, o1)) => {
let mut acc = g(init, o1);
let mut input = i1;
loop {
let _input = input.clone();
let len = input.input_len();
match f.parse(_input) {
Err(Err::Error(_)) => {
break;
}
Err(e) => return Err(e),
Ok((i, o)) => {
// infinite loop check: the parser must always consume
if i.input_len() == len {
return Err(Err::Failure(E::from_error_kind(i, ErrorKind::Many1)));
}
acc = g(acc, o);
input = i;
}
}
}
Ok((input, acc))
}
}
}
}
/// Repeats the embedded parser `m..=n` times, calling `g` to gather the results
///
/// This stops before `n` when the parser returns [`Err::Error`]. To instead chain an error up, see
/// [`cut`][crate::combinator::cut].
///
/// # Arguments
/// * `m` The minimum number of iterations.
/// * `n` The maximum number of iterations.
/// * `f` The parser to apply.
/// * `init` A function returning the initial value.
/// * `g` The function that combines a result of `f` with
/// the current accumulator.
///
/// *Note*: If the parser passed to `many1` accepts empty inputs
/// (like `alpha0` or `digit0`), `many1` will return an error,
/// to prevent going into an infinite loop.
///
/// ```rust
/// # use nom::{Err, error::ErrorKind, Needed, IResult};
/// use nom::multi::fold_many_m_n;
/// use nom::bytes::complete::tag;
///
/// fn parser(s: &str) -> IResult<&str, Vec<&str>> {
/// fold_many_m_n(
/// 0,
/// 2,
/// tag("abc"),
/// Vec::new,
/// |mut acc: Vec<_>, item| {
/// acc.push(item);
/// acc
/// }
/// )(s)
/// }
///
/// assert_eq!(parser("abcabc"), Ok(("", vec!["abc", "abc"])));
/// assert_eq!(parser("abc123"), Ok(("123", vec!["abc"])));
/// assert_eq!(parser("123123"), Ok(("123123", vec![])));
/// assert_eq!(parser(""), Ok(("", vec![])));
/// assert_eq!(parser("abcabcabc"), Ok(("abc", vec!["abc", "abc"])));
/// ```
pub fn fold_many_m_n<I, O, E, F, G, H, R>(
min: usize,
max: usize,
mut parse: F,
mut init: H,
mut fold: G,
) -> impl FnMut(I) -> IResult<I, R, E>
where
I: Clone + InputLength,
F: Parser<I, O, E>,
G: FnMut(R, O) -> R,
H: FnMut() -> R,
E: ParseError<I>,
{
move |mut input: I| {
if min > max {
return Err(Err::Failure(E::from_error_kind(input, ErrorKind::ManyMN)));
}
let mut acc = init();
for count in 0..max {
let len = input.input_len();
match parse.parse(input.clone()) {
Ok((tail, value)) => {
// infinite loop check: the parser must always consume
if tail.input_len() == len {
return Err(Err::Error(E::from_error_kind(tail, ErrorKind::ManyMN)));
}
acc = fold(acc, value);
input = tail;
}
//FInputXMError: handle failure properly
Err(Err::Error(err)) => {
if count < min {
return Err(Err::Error(E::append(input, ErrorKind::ManyMN, err)));
} else {
break;
}
}
Err(e) => return Err(e),
}
}
Ok((input, acc))
}
}
/// Gets a number from the parser and returns a
/// subslice of the input of that size.
/// If the parser returns `Incomplete`,
/// `length_data` will return an error.
/// # Arguments
/// * `f` The parser to apply.
/// ```rust
/// # use nom::{Err, error::ErrorKind, Needed, IResult};
/// use nom::number::complete::be_u16;
/// use nom::multi::length_data;
/// use nom::bytes::complete::tag;
///
/// fn parser(s: &[u8]) -> IResult<&[u8], &[u8]> {
/// length_data(be_u16)(s)
/// }
///
/// assert_eq!(parser(b"\x00\x03abcefg"), Ok((&b"efg"[..], &b"abc"[..])));
/// assert_eq!(parser(b"\x00\x03a"), Err(Err::Incomplete(Needed::new(2))));
/// ```
pub fn length_data<I, N, E, F>(mut f: F) -> impl FnMut(I) -> IResult<I, I, E>
where
I: InputLength + InputTake,
N: ToUsize,
F: Parser<I, N, E>,
E: ParseError<I>,
{
move |i: I| {
let (i, length) = f.parse(i)?;
let length: usize = length.to_usize();
if let Some(needed) = length
.checked_sub(i.input_len())
.and_then(NonZeroUsize::new)
{
Err(Err::Incomplete(Needed::Size(needed)))
} else {
Ok(i.take_split(length))
}
}
}
/// Gets a number from the first parser,
/// takes a subslice of the input of that size,
/// then applies the second parser on that subslice.
/// If the second parser returns `Incomplete`,
/// `length_value` will return an error.
/// # Arguments
/// * `f` The parser to apply.
/// * `g` The parser to apply on the subslice.
/// ```rust
/// # use nom::{Err, error::{Error, ErrorKind}, Needed, IResult};
/// use nom::number::complete::be_u16;
/// use nom::multi::length_value;
/// use nom::bytes::complete::tag;
///
/// fn parser(s: &[u8]) -> IResult<&[u8], &[u8]> {
/// length_value(be_u16, tag("abc"))(s)
/// }
///
/// assert_eq!(parser(b"\x00\x03abcefg"), Ok((&b"efg"[..], &b"abc"[..])));
/// assert_eq!(parser(b"\x00\x03123123"), Err(Err::Error(Error::new(&b"123"[..], ErrorKind::Tag))));
/// assert_eq!(parser(b"\x00\x03a"), Err(Err::Incomplete(Needed::new(2))));
/// ```
pub fn length_value<I, O, N, E, F, G>(mut f: F, mut g: G) -> impl FnMut(I) -> IResult<I, O, E>
where
I: Clone + InputLength + InputTake,
N: ToUsize,
F: Parser<I, N, E>,
G: Parser<I, O, E>,
E: ParseError<I>,
{
move |i: I| {
let (i, length) = f.parse(i)?;
let length: usize = length.to_usize();
if let Some(needed) = length
.checked_sub(i.input_len())
.and_then(NonZeroUsize::new)
{
Err(Err::Incomplete(Needed::Size(needed)))
} else {
let (rest, i) = i.take_split(length);
match g.parse(i.clone()) {
Err(Err::Incomplete(_)) => Err(Err::Error(E::from_error_kind(i, ErrorKind::Complete))),
Err(e) => Err(e),
Ok((_, o)) => Ok((rest, o)),
}
}
}
}
/// Gets a number from the first parser,
/// then applies the second parser that many times.
/// # Arguments
/// * `f` The parser to apply to obtain the count.
/// * `g` The parser to apply repeatedly.
/// ```rust
/// # use nom::{Err, error::{Error, ErrorKind}, Needed, IResult};
/// use nom::number::complete::u8;
/// use nom::multi::length_count;
/// use nom::bytes::complete::tag;
/// use nom::combinator::map;
///
/// fn parser(s: &[u8]) -> IResult<&[u8], Vec<&[u8]>> {
/// length_count(map(u8, |i| {
/// println!("got number: {}", i);
/// i
/// }), tag("abc"))(s)
/// }
///
/// assert_eq!(parser(&b"\x02abcabcabc"[..]), Ok(((&b"abc"[..], vec![&b"abc"[..], &b"abc"[..]]))));
/// assert_eq!(parser(b"\x03123123123"), Err(Err::Error(Error::new(&b"123123123"[..], ErrorKind::Tag))));
/// ```
#[cfg(feature = "alloc")]
pub fn length_count<I, O, N, E, F, G>(mut f: F, mut g: G) -> impl FnMut(I) -> IResult<I, Vec<O>, E>
where
I: Clone,
N: ToUsize,
F: Parser<I, N, E>,
G: Parser<I, O, E>,
E: ParseError<I>,
{
move |i: I| {
let (i, count) = f.parse(i)?;
let mut input = i.clone();
let mut res = Vec::new();
for _ in 0..count.to_usize() {
let input_ = input.clone();
match g.parse(input_) {
Ok((i, o)) => {
res.push(o);
input = i;
}
Err(Err::Error(e)) => {
return Err(Err::Error(E::append(i, ErrorKind::Count, e)));
}
Err(e) => {
return Err(e);
}
}
}
Ok((input, res))
}
}