From 694a9a4ecb4f743ab7958a66a042381a812ad156 Mon Sep 17 00:00:00 2001
From: Matthias Beyer <mail@beyermatthias.de>
Date: Tue, 26 Sep 2017 17:18:03 +0200
Subject: Add Matcher trait for indicators

---
 src/error.rs   |  5 +++++
 src/lib.rs     |  1 +
 src/matcher.rs | 37 +++++++++++++++++++++++++++++++++++++
 3 files changed, 43 insertions(+)
 create mode 100644 src/matcher.rs

diff --git a/src/error.rs b/src/error.rs
index d450146..39d482f 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -33,6 +33,11 @@ error_chain! {
             display("The passed argument is not an amount: {:?}", tt)
         }
 
+        ArgumentErrorNotAMoment(name: &'static str) {
+            description("Argument Error: Not a moment TimeType object")
+            display("The passed argument is not a moment, but a {}", name)
+        }
+
         CannotCalculateEndOfYearOn(tt: TimeType) {
             description("Argument Error: Cannot calculate end-of-year")
             display("Argument Error: Cannot calculate end-of-year on a {:?}", tt)
diff --git a/src/lib.rs b/src/lib.rs
index 60bcfc1..e861ccd 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -7,5 +7,6 @@ pub mod iter;
 pub mod result;
 pub mod timetype;
 pub mod indicator;
+pub mod matcher;
 mod util;
 
diff --git a/src/matcher.rs b/src/matcher.rs
new file mode 100644
index 0000000..1482b68
--- /dev/null
+++ b/src/matcher.rs
@@ -0,0 +1,37 @@
+
+use chrono::Datelike;
+
+use error::KairosError as KE;
+use error::KairosErrorKind as KEK;
+use error::Result;
+use indicator::Day;
+use indicator::Month;
+use timetype::TimeType;
+
+/// A trait to extend indicator::* to be able to match them with a TimeType object
+pub trait Matcher {
+    fn matches(&self, tt: &TimeType) -> Result<bool>;
+}
+
+impl Matcher for Day {
+
+    fn matches(&self, tt: &TimeType) -> Result<bool> {
+        let this : ::chrono::Weekday = self.clone().into();
+        tt.get_moment()
+            .map(|mom| this == mom.weekday())
+            .ok_or(KE::from_kind(KEK::ArgumentErrorNotAMoment(tt.name())))
+    }
+}
+
+impl Matcher for Month {
+
+    fn matches(&self, tt: &TimeType) -> Result<bool> {
+        let this : u32 = self.clone().into();
+        tt.get_moment()
+            .map(|mom| this == mom.month())
+            .ok_or(KE::from_kind(KEK::ArgumentErrorNotAMoment(tt.name())))
+    }
+
+}
+
+
-- 
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