wordy: WordProblem::answer() now returns Option

Author: ZapAnton

exercises/wordy/example.rs

@@ -32,20 +32,20 @@ impl WordProblem {
         }
     }
 
-    pub fn answer(&self) -> Result<isize, ()> {
+    pub fn answer(&self) -> Option<isize> {
         let mut t = self.tokens();
         let mut result: isize = 0;
         let mut opr = "plus".to_string();
 
         if t.len() <= 1 {
-            Err(())
+            None
         } else {
             while t.len() > 1 {
                 result = self.evaluate(result, opr, self.operand(&t.remove(0)));
                 opr = self.operator(&t.remove(0));
             }
             result = self.evaluate(result, opr, self.operand(&t.remove(0)));
-            Ok(result)
+            Some(result)
         }
     }
 

exercises/wordy/src/lib.rs

@@ -8,7 +8,7 @@ impl WordProblem {
         );
     }
 
-    pub fn answer(&self) -> Result<i32, String> {
+    pub fn answer(&self) -> Option<i32> {
         unimplemented!(
             "Return the result of the transmitted command, or an error, if the command is invalid."
         );

exercises/wordy/tests/wordy.rs

@@ -5,110 +5,110 @@ use wordy::*;
 #[test]
 fn addition() {
     let command = "What is 1 plus 1?";
-    assert_eq!(Ok(2), WordProblem::new(command).answer());
+    assert_eq!(Some(2), WordProblem::new(command).answer());
 }
 
 #[test]
 #[ignore]
 fn more_addition() {
     let command = "What is 53 plus 2?";
-    assert_eq!(Ok(55), WordProblem::new(command).answer());
+    assert_eq!(Some(55), WordProblem::new(command).answer());
 }
 
 #[test]
 #[ignore]
 fn addition_with_negative_numbers() {
     let command = "What is -1 plus -10?";
-    assert_eq!(Ok(-11), WordProblem::new(command).answer());
+    assert_eq!(Some(-11), WordProblem::new(command).answer());
 }
 
 #[test]
 #[ignore]
 fn large_addition() {
     let command = "What is 123 plus 45678?";
-    assert_eq!(Ok(45801), WordProblem::new(command).answer());
+    assert_eq!(Some(45801), WordProblem::new(command).answer());
 }
 
 #[test]
 #[ignore]
 fn subtraction() {
     let command = "What is 4 minus -12?";
-    assert_eq!(Ok(16), WordProblem::new(command).answer());
+    assert_eq!(Some(16), WordProblem::new(command).answer());
 }
 
 #[test]
 #[ignore]
 fn multiplication() {
     let command = "What is -3 multiplied by 25?";
-    assert_eq!(Ok(-75), WordProblem::new(command).answer());
+    assert_eq!(Some(-75), WordProblem::new(command).answer());
 }
 
 #[test]
 #[ignore]
 fn division() {
     let command = "What is 33 divided by -3?";
-    assert_eq!(Ok(-11), WordProblem::new(command).answer());
+    assert_eq!(Some(-11), WordProblem::new(command).answer());
 }
 
 #[test]
 #[ignore]
 fn multiple_additions() {
     let command = "What is 1 plus 1 plus 1?";
-    assert_eq!(Ok(3), WordProblem::new(command).answer());
+    assert_eq!(Some(3), WordProblem::new(command).answer());
 }
 
 #[test]
 #[ignore]
 fn addition_and_subtraction() {
     let command = "What is 1 plus 5 minus -2?";
-    assert_eq!(Ok(8), WordProblem::new(command).answer());
+    assert_eq!(Some(8), WordProblem::new(command).answer());
 }
 
 #[test]
 #[ignore]
 fn multiple_subtraction() {
     let command = "What is 20 minus 4 minus 13?";
-    assert_eq!(Ok(3), WordProblem::new(command).answer());
+    assert_eq!(Some(3), WordProblem::new(command).answer());
 }
 
 #[test]
 #[ignore]
 fn subtraction_then_addition() {
     let command = "What is 17 minus 6 plus 3?";
-    assert_eq!(Ok(14), WordProblem::new(command).answer());
+    assert_eq!(Some(14), WordProblem::new(command).answer());
 }
 
 #[test]
 #[ignore]
 fn multiple_multiplications() {
     let command = "What is 2 multiplied by -2 multiplied by 3?";
-    assert_eq!(Ok(-12), WordProblem::new(command).answer());
+    assert_eq!(Some(-12), WordProblem::new(command).answer());
 }
 
 #[test]
 #[ignore]
 fn addition_and_multiplication() {
     let command = "What is -3 plus 7 multiplied by -2?";
-    assert_eq!(Ok(-8), WordProblem::new(command).answer());
+    assert_eq!(Some(-8), WordProblem::new(command).answer());
 }
 
 #[test]
 #[ignore]
 fn multiple_divisions() {
     let command = "What is -12 divided by 2 divided by -3?";
-    assert_eq!(Ok(2), WordProblem::new(command).answer());
+    assert_eq!(Some(2), WordProblem::new(command).answer());
 }
 
 #[test]
 #[ignore]
 fn unknown_operation() {
     let command = "What is 52 cubed?";
-    assert!(WordProblem::new(command).answer().is_err());
+    assert!(WordProblem::new(command).answer().is_none());
 }
 
 #[test]
 #[ignore]
 fn non_math_question() {
     let command = "Who is the President of the United States?";
-    assert!(WordProblem::new(command).answer().is_err());
+    assert!(WordProblem::new(command).answer().is_none());
 }