addition: TryInto i64

src/lib.rs

@@ -10,6 +10,7 @@ pub enum FractionError {
     DivisionByZero,
     ZeroDenominator,
     Overflow,
+    InvalidInteger,
 }
 
 impl fmt::Display for FractionError {
@@ -18,6 +19,7 @@ impl fmt::Display for FractionError {
             FractionError::DivisionByZero => write!(f, "Division by zero"),
             FractionError::ZeroDenominator => write!(f, "Denominator can't be zero"),
             FractionError::Overflow => write!(f, "Numeric overflow"),
+            FractionError::InvalidInteger => write!(f, "Can't convert to integer"),
         }
     }
 }
@@ -203,6 +205,18 @@ impl TryFrom<(i64, i64)> for Fraction {
     }
 }
 
+impl TryInto<i64> for Fraction {
+    type Error = FractionError;
+
+    fn try_into(self) -> Result<i64, Self::Error> {
+        if self.den != 1 {
+            return Err(FractionError::InvalidInteger);
+        }
+
+        Ok(self.num)
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;