13: Add solutions for section "errors".

Dependencies

• [2] H6XH45OP 0

Change contents

• edit in exercises/error_handling/errors6.rs at line 10
  [2.132937]→[2.132937:132955](∅→∅)
  −

  − // I AM NOT DONE
• replacement in exercises/error_handling/errors6.rs at line 24
  [2.133326]→[2.133326:133383](∅→∅)
  − // TODO: add another error conversion function here.
  [2.133326]

  [2.133383]
  +

  + fn from_parse_int(err: ParseIntError) -> ParsePosNonzeroError {

  + ParsePosNonzeroError::ParseInt(err)

  + }
• replacement in exercises/error_handling/errors6.rs at line 33
  [2.133478]→[2.133478:133632](∅→∅)
  − // TODO: change this to return an appropriate error instead of panicking

  − // when `parse()` returns an error.

  − let x: i64 = s.parse().unwrap();
  [2.133478]

  [2.133632]
  + let x: i64 = s.parse()

  + .map_err(ParsePosNonzeroError::from_parse_int)?;

  +
• edit in exercises/error_handling/errors5.rs at line 6
  [2.135266]→[2.135266:135284](∅→∅)
  −

  − // I AM NOT DONE
• replacement in exercises/error_handling/errors5.rs at line 12
  [2.135411]→[2.135411:135452](∅→∅)
  − fn main() -> Result<(), ParseIntError> {
  [2.135411]

  [2.135452]
  + fn main() -> Result<(), Box<dyn error::Error>> {
• replacement in exercises/error_handling/errors4.rs at line 4
  [2.136640]→[2.136640:136657](∅→∅)
  − // I AM NOT DONE
  [2.136640]

  [2.136657]
  + use std::cmp::Ordering::{Less, Equal, Greater};
• replacement in exercises/error_handling/errors4.rs at line 17
  [2.136903]→[2.136903:136952](∅→∅)
  − Ok(PositiveNonzeroInteger(value as u64))
  [2.136903]

  [2.136952]
  + match value.cmp(&0) {

  + Less => Err(CreationError::Negative),

  + Equal => Err(CreationError::Zero),

  + Greater => Ok(PositiveNonzeroInteger(value as u64)),

  + }
• edit in exercises/error_handling/errors3.rs at line 6
  [2.137509]→[2.137509:137527](∅→∅)
  −

  − // I AM NOT DONE
• replacement in exercises/error_handling/errors3.rs at line 9
  [2.137558]→[2.137558:137570](∅→∅)
  − fn main() {
  [2.137558]

  [2.137570]
  + fn main() -> Result<(), ParseIntError> {
• edit in exercises/error_handling/errors3.rs at line 21
  [2.137848]

  [2.137848]
  +

  + Ok(())
• edit in exercises/error_handling/errors2.rs at line 18
  [2.139102]→[2.139102:139120](∅→∅)
  −

  − // I AM NOT DONE
• replacement in exercises/error_handling/errors2.rs at line 26
  [2.139322]→[2.139322:139367](∅→∅)
  − Ok(qty * cost_per_item + processing_fee)
  [2.139322]

  [2.139367]
  + Ok(qty? * cost_per_item + processing_fee)
• replacement in exercises/error_handling/errors1.rs at line 9
  [2.140152]→[2.140152:140233](∅→∅)
  − // I AM NOT DONE

  −

  − pub fn generate_nametag_text(name: String) -> Option<String> {
  [2.140152]

  [2.140233]
  + pub fn generate_nametag_text(name: String) -> Result<String, String> {
• replacement in exercises/error_handling/errors1.rs at line 11
  [2.140257]→[2.140257:140306](∅→∅)
  − Some(format!("Hi! My name is {}", name))
  [2.140257]

  [2.140306]
  + Ok(format!("Hi! My name is {}", name))
• replacement in exercises/error_handling/errors1.rs at line 14
  [2.140358]→[2.140358:140371](∅→∅)
  − None
  [2.140358]

  [2.140371]
  + Err(String::from("`name` was empty; it must be nonempty."))
• replacement in exercises/error_handling/errors1.rs at line 29
  [2.140731]→[2.140731:140782](∅→∅)
  − Some("Hi! My name is Beyoncé".into())
  [2.140731]

  [2.140782]
  + Ok("Hi! My name is Beyoncé".into())