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- //
- // imag - the personal information management suite for the commandline
- // Copyright (C) 2015, 2016 Matthias Beyer <mail@beyermatthias.de> and contributors
- //
- // This library is free software; you can redistribute it and/or
- // modify it under the terms of the GNU Lesser General Public
- // License as published by the Free Software Foundation; version
- // 2.1 of the License.
- //
- // This library is distributed in the hope that it will be useful,
- // but WITHOUT ANY WARRANTY; without even the implied warranty of
- // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- // Lesser General Public License for more details.
- //
- // You should have received a copy of the GNU Lesser General Public
- // License along with this library; if not, write to the Free Software
- // Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
- //
- /// Folds its contents to a result.
- pub trait FoldResult: Sized {
- type Item;
- /// Processes all contained items returning the last successful result or the first error.
- /// If there are no items, returns `Ok(R::default())`.
- fn fold_defresult<R, E, F>(self, func: F) -> Result<R, E>
- where R: Default,
- F: FnMut(Self::Item)
- -> Result<R, E>
- {
- self.fold_result(R::default(), func)
- }
- /// Processes all contained items returning the last successful result or the first error.
- /// If there are no items, returns `Ok(default)`.
- fn fold_result<R, E, F>(self, default: R, mut func: F) -> Result<R, E>
- where F: FnMut(Self::Item) -> Result<R, E>;
- }
- impl<X, I: Iterator<Item = X>> FoldResult for I {
- type Item = X;
- fn fold_result<R, E, F>(self, default: R, mut func: F) -> Result<R, E>
- where F: FnMut(Self::Item) -> Result<R, E>
- {
- self.fold(Ok(default), |acc, item| acc.and_then(|_| func(item)))
- }
- }
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