Add module for debug logging in iteratorslogging

3 files changed, 52 insertions, 0 deletions

diff --git a/Cargo.toml b/Cargo.toml
index cc9d1fe..6fa2a50 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -14,3 +14,11 @@ documentation = "https://docs.rs/resiter"
 repository    = "https://github.com/matthiasbeyer/resiter"
 
 [dependencies]
+
+[dependencies.log]
+version  = "0.4"
+optional = true
+
+[features]
+default = []
+logging = ["log"]
diff --git a/src/lib.rs b/src/lib.rs
index ff4ecc3..56e6bd7 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -194,6 +194,13 @@
 //! MPL 2.0
 //!
 
+#[cfg(feature = "logging")]
+#[macro_use]
+extern crate log;
+
+#[cfg(feature = "logging")]
+pub mod logging;
+
 pub mod and_then;
 pub mod errors;
 pub mod filter;
diff --git a/src/logging.rs b/src/logging.rs
new file mode 100644
index 0000000..32ca0b2
--- /dev/null
+++ b/src/logging.rs
@@ -0,0 +1,37 @@
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at http://mozilla.org/MPL/2.0/.
+//
+
+pub mod debug {
+
+    pub trait IterDebug<'a, I, T>
+        where I: Iterator<Item = T>
+    {
+        fn debug(self, s: &'a str) -> DoIterDebug<'a, I, T>;
+    }
+
+    impl<'a, I, T> IterDebug<'a, I, T> for I
+        where I: Iterator<Item = T>
+    {
+        fn debug(self, s: &'a str) -> DoIterDebug<'a, I, T> {
+            DoIterDebug(self, s)
+        }
+    }
+
+
+    pub struct DoIterDebug<'a, I, T>(I, &'a str) where I: Iterator<Item = T>;
+
+    impl<'a, I, T> Iterator for DoIterDebug<'a, I, T>
+        where I: Iterator<Item = T>
+    {
+        type Item = T;
+
+        fn next(&mut self) -> Option<Self::Item> {
+            debug!("{}", self.1);
+            self.0.next()
+        }
+    }
+
+}