Add a `fold_ok` utility.

Add a utility that folds an iterator into a result and uses it to reduce
boilerplate in the codebase.

2 files changed, 9 insertions, 0 deletions

diff --git a/libimagutil/src/iter.rs b/libimagutil/src/iter.rs
new file mode 100644
index 00000000..0f682bff
--- /dev/null
+++ b/libimagutil/src/iter.rs
@@ -0,0 +1,8 @@
+/// Processes `iter` returning the last successful result or the first error.
+pub fn fold_ok<X, I, R, E, F>(iter: I, mut func: F) -> Result<R, E>
+    where I: Iterator<Item = X>,
+          R: Default,
+          F: FnMut(X) -> Result<R, E>
+{
+    iter.fold(Ok(R::default()), |acc, item| acc.and_then(|_| func(item)))
+}
diff --git a/libimagutil/src/lib.rs b/libimagutil/src/lib.rs
index bde49b00..730970e8 100644
--- a/libimagutil/src/lib.rs
+++ b/libimagutil/src/lib.rs
@@ -18,5 +18,6 @@
 extern crate regex;
 
 pub mod ismatch;
+pub mod iter;
 pub mod key_value_split;
 pub mod variants;