generics1 done

exercises/error_handling/errors5.rs

@@ -4,14 +4,12 @@
 // It won't compile right now! Why?
 // Execute `rustlings hint errors5` for hints!
 
-// I AM NOT DONE
-
 use std::error;
 use std::fmt;
 use std::num::ParseIntError;
 
 // TODO: update the return type of `main()` to make this compile.
-fn main() -> Result<(), ParseIntError> {
+fn main() -> Result<(), Box<dyn error::Error>> {
     let pretend_user_input = "42";
     let x: i64 = pretend_user_input.parse()?;
     println!("output={:?}", PositiveNonzeroInteger::new(x)?);
@@ -34,7 +32,7 @@ impl PositiveNonzeroInteger {
         match value {
             x if x < 0 => Err(CreationError::Negative),
             x if x == 0 => Err(CreationError::Zero),
-            x => Ok(PositiveNonzeroInteger(x as u64))
+            x => Ok(PositiveNonzeroInteger(x as u64)),
         }
     }
 }

exercises/error_handling/errors6.rs

@@ -8,29 +8,30 @@
 
 // Make these tests pass! Execute `rustlings hint errors6` for hints :)
 
-// I AM NOT DONE
-
 use std::num::ParseIntError;
 
 // This is a custom error type that we will be using in `parse_pos_nonzero()`.
 #[derive(PartialEq, Debug)]
 enum ParsePosNonzeroError {
     Creation(CreationError),
-    ParseInt(ParseIntError)
+    ParseInt(ParseIntError),
 }
 
 impl ParsePosNonzeroError {
     // TODO: add another error conversion function here.
+    fn from_creation(err: CreationError) -> ParsePosNonzeroError {
+        ParsePosNonzeroError::Creation(err)
+    }
+    fn from_parse_int(err: ParseIntError) -> ParsePosNonzeroError {
+        ParsePosNonzeroError::ParseInt(err)
+    }
 }
 
-fn parse_pos_nonzero(s: &str)
-    -> Result<PositiveNonzeroInteger, ParsePosNonzeroError>
-{
+fn parse_pos_nonzero(s: &str) -> Result<PositiveNonzeroInteger, ParsePosNonzeroError> {
     // TODO: change this to return an appropriate error instead of panicking
     // when `parse()` returns an error.
-    let x: i64 = s.parse().unwrap();
-    PositiveNonzeroInteger::new(x)
-        .map_err(ParsePosNonzeroError::from_creation)
+    let x: i64 = s.parse().map_err(ParsePosNonzeroError::from_parse_int)?;
+    PositiveNonzeroInteger::new(x).map_err(ParsePosNonzeroError::from_creation)
 }
 
 // Don't change anything below this line.
@@ -49,7 +50,7 @@ impl PositiveNonzeroInteger {
         match value {
             x if x < 0 => Err(CreationError::Negative),
             x if x == 0 => Err(CreationError::Zero),
-            x => Ok(PositiveNonzeroInteger(x as u64))
+            x => Ok(PositiveNonzeroInteger(x as u64)),
         }
     }
 }

exercises/generics/generics1.rs

@@ -3,9 +3,7 @@
 
 // Execute `rustlings hint generics1` for hints!
 
-// I AM NOT DONE
-
 fn main() {
-    let mut shopping_list: Vec<?> = Vec::new();
+    let mut shopping_list: Vec<&str> = Vec::new();
     shopping_list.push("milk");
 }