From facdad6f62446f2b04330a88699d7c0cb2d70217 Mon Sep 17 00:00:00 2001
From: enforcer007 <akhilgodvsdemon@gmail.com>
Date: Sun, 13 Nov 2022 14:25:50 +0530
Subject: [PATCH] errors

---
 exercises/error_handling/errors1.rs |  9 +++------
 exercises/error_handling/errors2.rs |  5 +----
 exercises/error_handling/errors3.rs |  5 ++---
 exercises/error_handling/errors4.rs | 10 +++++++---
 exercises/error_handling/errors5.rs |  4 +---
 exercises/error_handling/errors6.rs |  8 +++++---
 6 files changed, 19 insertions(+), 22 deletions(-)

diff --git a/exercises/error_handling/errors1.rs b/exercises/error_handling/errors1.rs
index bcee9723..0e4e9708 100644
--- a/exercises/error_handling/errors1.rs
+++ b/exercises/error_handling/errors1.rs
@@ -5,17 +5,14 @@
 // construct to `Option` that can be used to express error conditions. Let's use it!
 // Execute `rustlings hint errors1` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
-pub fn generate_nametag_text(name: String) -> Option<String> {
+pub fn generate_nametag_text(name: String) -> Result<String, String> {
     if name.is_empty() {
         // Empty names aren't allowed.
-        None
+        Err("`name` was empty; it must be nonempty.".into())
     } else {
-        Some(format!("Hi! My name is {}", name))
+        Ok(format!("Hi! My name is {}", name))
     }
 }
-
 #[cfg(test)]
 mod tests {
     use super::*;
diff --git a/exercises/error_handling/errors2.rs b/exercises/error_handling/errors2.rs
index 1cd8fc66..fecbe1b5 100644
--- a/exercises/error_handling/errors2.rs
+++ b/exercises/error_handling/errors2.rs
@@ -17,14 +17,11 @@
 // one is a lot shorter!
 // Execute `rustlings hint errors2` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 use std::num::ParseIntError;
-
 pub fn total_cost(item_quantity: &str) -> Result<i32, ParseIntError> {
     let processing_fee = 1;
     let cost_per_item = 5;
-    let qty = item_quantity.parse::<i32>();
+    let qty = item_quantity.parse::<i32>()?;
 
     Ok(qty * cost_per_item + processing_fee)
 }
diff --git a/exercises/error_handling/errors3.rs b/exercises/error_handling/errors3.rs
index a2d2d190..c9784e3d 100644
--- a/exercises/error_handling/errors3.rs
+++ b/exercises/error_handling/errors3.rs
@@ -4,11 +4,9 @@
 // Why not? What should we do to fix it?
 // Execute `rustlings hint errors3` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 use std::num::ParseIntError;
 
-fn main() {
+fn main() -> Result<(), ParseIntError> {
     let mut tokens = 100;
     let pretend_user_input = "8";
 
@@ -20,6 +18,7 @@ fn main() {
         tokens -= cost;
         println!("You now have {} tokens.", tokens);
     }
+    Ok(())
 }
 
 pub fn total_cost(item_quantity: &str) -> Result<i32, ParseIntError> {
diff --git a/exercises/error_handling/errors4.rs b/exercises/error_handling/errors4.rs
index 0efe8ccd..1a572e1f 100644
--- a/exercises/error_handling/errors4.rs
+++ b/exercises/error_handling/errors4.rs
@@ -1,8 +1,6 @@
 // errors4.rs
 // Execute `rustlings hint errors4` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 #[derive(PartialEq, Debug)]
 struct PositiveNonzeroInteger(u64);
 
@@ -15,7 +13,13 @@ enum CreationError {
 impl PositiveNonzeroInteger {
     fn new(value: i64) -> Result<PositiveNonzeroInteger, CreationError> {
         // Hmm...? Why is this only returning an Ok value?
-        Ok(PositiveNonzeroInteger(value as u64))
+        if value < 0 {
+            Err(CreationError::Negative)
+        } else if value == 0 {
+            Err(CreationError::Zero)
+        } else {
+            Ok(PositiveNonzeroInteger(value as u64))
+        }
     }
 }
 
diff --git a/exercises/error_handling/errors5.rs b/exercises/error_handling/errors5.rs
index 6da06ef3..f93f705c 100644
--- a/exercises/error_handling/errors5.rs
+++ b/exercises/error_handling/errors5.rs
@@ -16,14 +16,12 @@
 
 // Execute `rustlings hint errors5` or use the `hint` watch subcommand for a hint.
 
-// 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<(), Box<dyn ???>> {
+fn main() -> Result<(), Box<dyn error::Error>> {
     let pretend_user_input = "42";
     let x: i64 = pretend_user_input.parse()?;
     println!("output={:?}", PositiveNonzeroInteger::new(x)?);
diff --git a/exercises/error_handling/errors6.rs b/exercises/error_handling/errors6.rs
index 8097b490..ff25be41 100644
--- a/exercises/error_handling/errors6.rs
+++ b/exercises/error_handling/errors6.rs
@@ -8,8 +8,6 @@
 
 // Execute `rustlings hint errors6` or use the `hint` watch subcommand for a hint.
 
-// I AM NOT DONE
-
 use std::num::ParseIntError;
 
 // This is a custom error type that we will be using in `parse_pos_nonzero()`.
@@ -25,12 +23,16 @@ impl ParsePosNonzeroError {
     }
     // TODO: add another error conversion function here.
     // fn from_parseint...
+    fn from_parseint(err: ParseIntError) -> ParsePosNonzeroError {
+        ParsePosNonzeroError::ParseInt(err)
+    }
 }
 
 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();
+
+    let x: i64 = s.parse().map_err(ParsePosNonzeroError::from_parseint)?;
     PositiveNonzeroInteger::new(x).map_err(ParsePosNonzeroError::from_creation)
 }