impl less than;

Author: tomoikey

src/rule/number.rs

@@ -1,4 +1,5 @@
 mod even;
+mod less;
 mod odd;
 
 pub use even::*;

src/rule/number/less.rs

@@ -0,0 +1,42 @@
+#[macro_export]
+macro_rules! less_rule {
+    (($e: literal, $t: ty)) => {
+        paste::item! {
+            pub type [<Less $e $t>] = $crate::Refined<[<LessRule $e $t>]>;
+            pub struct [<LessRule $e $t>];
+
+            impl $crate::rule::Rule for [<LessRule $e $t>] {
+                type Item = $t;
+
+                fn validate(target: Self::Item) -> Result<Self::Item, $crate::result::Error<Self::Item>> {
+                    if target < $e {
+                        Ok(target)
+                    } else {
+                        Err($crate::result::Error::new(format!("{} is not less than {}", target, $e), target))
+                    }
+                }
+            }
+        }
+    };
+    ($t: ty, $($ts: ty),+) => {
+        odd_rule! {$t}
+        odd_rule! {$($ts), +}
+    };
+}
+
+#[cfg(test)]
+mod test {
+    less_rule!((50, i8));
+
+    #[test]
+    fn test_less_than_50i8_ok() {
+        let less_result = Less50i8::new(1);
+        assert!(less_result.is_ok());
+    }
+
+    #[test]
+    fn test_less_than_50i8_err() {
+        let less_result = Less50i8::new(50);
+        assert!(less_result.is_err());
+    }
+}