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Remove unfold #610

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Remove unfold #610

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4 changes: 2 additions & 2 deletions src/lib.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -145,7 +145,7 @@ pub mod structs {
pub use crate::rciter_impl::RcIter;
pub use crate::repeatn::RepeatN;
#[allow(deprecated)]
pub use crate::sources::{RepeatCall, Unfold, Iterate};
pub use crate::sources::{RepeatCall, Iterate};
#[cfg(feature = "use_alloc")]
pub use crate::tee::Tee;
pub use crate::tuple_impl::{TupleBuffer, TupleWindows, CircularTupleWindows, Tuples};
Expand Down Expand Up @@ -177,7 +177,7 @@ pub use crate::peeking_take_while::PeekingNext;
pub use crate::process_results_impl::process_results;
pub use crate::repeatn::repeat_n;
#[allow(deprecated)]
pub use crate::sources::{repeat_call, unfold, iterate};
pub use crate::sources::{repeat_call, iterate};
pub use crate::with_position::Position;
pub use crate::unziptuple::{multiunzip, MultiUnzip};
pub use crate::ziptuple::multizip;
Expand Down
71 changes: 0 additions & 71 deletions src/sources.rs
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Expand Up @@ -61,77 +61,6 @@ impl<A, F> Iterator for RepeatCall<F>
}
}

/// Creates a new unfold source with the specified closure as the "iterator
/// function" and an initial state to eventually pass to the closure
///
/// `unfold` is a general iterator builder: it has a mutable state value,
/// and a closure with access to the state that produces the next value.
///
/// This more or less equivalent to a regular struct with an [`Iterator`]
/// implementation, and is useful for one-off iterators.
///
/// ```
/// // an iterator that yields sequential Fibonacci numbers,
/// // and stops at the maximum representable value.
///
/// use itertools::unfold;
///
/// let mut fibonacci = unfold((1u32, 1u32), |(x1, x2)| {
/// // Attempt to get the next Fibonacci number
/// let next = x1.saturating_add(*x2);
///
/// // Shift left: ret <- x1 <- x2 <- next
/// let ret = *x1;
/// *x1 = *x2;
/// *x2 = next;
///
/// // If addition has saturated at the maximum, we are finished
/// if ret == *x1 && ret > 1 {
/// None
/// } else {
/// Some(ret)
/// }
/// });
///
/// itertools::assert_equal(fibonacci.by_ref().take(8),
/// vec![1, 1, 2, 3, 5, 8, 13, 21]);
/// assert_eq!(fibonacci.last(), Some(2_971_215_073))
/// ```
pub fn unfold<A, St, F>(initial_state: St, f: F) -> Unfold<St, F>
where F: FnMut(&mut St) -> Option<A>
{
Unfold {
f,
state: initial_state,
}
}

impl<St, F> fmt::Debug for Unfold<St, F>
where St: fmt::Debug,
{
debug_fmt_fields!(Unfold, state);
}

/// See [`unfold`](crate::unfold) for more information.
#[derive(Clone)]
#[must_use = "iterators are lazy and do nothing unless consumed"]
pub struct Unfold<St, F> {
f: F,
/// Internal state that will be passed to the closure on the next iteration
pub state: St,
}

impl<A, St, F> Iterator for Unfold<St, F>
where F: FnMut(&mut St) -> Option<A>
{
type Item = A;

#[inline]
fn next(&mut self) -> Option<Self::Item> {
(self.f)(&mut self.state)
}
}

/// An iterator that infinitely applies function to value and yields results.
///
/// This `struct` is created by the [`iterate()`](crate::iterate) function.
Expand Down