2018: switch to anyhow

Cargo.lock

@@ -27,6 +27,7 @@ dependencies = [
 name = "aoc2018"
 version = "0.1.0"
 dependencies = [
+ "anyhow",
  "aoc",
  "criterion",
 ]

aoc2018/Cargo.toml

@@ -13,6 +13,7 @@ criterion = "0.3"
 [dependencies]
 
 aoc = { path = "../aoc" }
+anyhow = "1.0"
 
 [lib]
 path = "src/lib.rs"

aoc2018/src/day01.rs

@@ -1,7 +1,7 @@
 use std::collections::HashSet;
 use std::fmt::Write;
 
-use aoc::Result;
+use anyhow::Result;
 
 const INPUT: &str = include_str!("../input/day01.txt");
 

aoc2018/src/day02.rs

@@ -1,7 +1,7 @@
 use std::collections::HashMap;
 use std::fmt::Write;
 
-use aoc::Result;
+use anyhow::Result;
 
 const INPUT: &str = include_str!("../input/day02.txt");
 

aoc2018/src/day03.rs

@@ -1,11 +1,9 @@
 use std::collections::HashMap;
 use std::collections::HashSet;
-use std::error::Error;
 use std::fmt::Write;
 use std::str::FromStr;
 
-use aoc::err;
+use anyhow::{Context, Result};
-use aoc::Result;
 
 const INPUT: &str = include_str!("../input/day03.txt");
 
@@ -27,7 +25,7 @@ struct Claim {
 }
 
 impl FromStr for Claim {
-    type Err = Box<dyn Error>;
+    type Err = anyhow::Error;
 
     /// Parses a claim from a line
     ///
@@ -41,22 +39,20 @@ impl FromStr for Claim {
         let s = &s[1..];
 
         // find ' @ ' separator
-        let at = s
+        let at = s.find(" @ ").context("` @ ` delimiter not found")?;
-            .find(" @ ")
-            .ok_or_else(|| err!("` @ ` delimiter not found"))?;
         let id = s[..at].parse()?;
         let s = &s[(at + 3)..];
 
         // parse 'X,Y: WxH
-        let comma = s.find(',').ok_or_else(|| err!("`,` delimiter not found"))?;
+        let comma = s.find(',').context("`,` delimiter not found")?;
-        let colon = s.find(':').ok_or_else(|| err!("`:` delimiter not found"))?;
+        let colon = s.find(':').context("`:` delimiter not found")?;
         let x = s[..comma].parse()?;
         let y = s[(comma + 1)..colon].parse()?;
 
         // reduce line to 'WxH'
         let s = &s[(colon + 2)..];
 
-        let sep = s.find('x').ok_or_else(|| err!("`x` delimiter not found"))?;
+        let sep = s.find('x').context("`x` delimiter not found")?;
         let width = s[..sep].parse()?;
         let height = s[(sep + 1)..].parse()?;
 
@@ -77,7 +73,7 @@ fn part1(input: &str) -> Result<u64> {
     for line in input.lines() {
         let claim: Claim = line
             .parse()
-            .or_else(|e| Err(err!("couldn't parse line: `{}`, {}", line, e)))?;
+            .with_context(|| format!("couldn't parse line: `{}`", line))?;
 
         for i in 0..claim.width {
             for j in 0..claim.height {
@@ -106,7 +102,7 @@ fn part2(input: &str) -> Result<usize> {
     for line in input.lines() {
         let claim: Claim = line
             .parse()
-            .or_else(|e| Err(err!("couldn't parse line: `{}`, {}", line, e)))?;
+            .with_context(|| format!("couldn't parse line: `{}`", line))?;
         set.insert(claim.id);
 
         for i in 0..claim.width {

aoc2018/src/day04.rs

@@ -1,10 +1,8 @@
 use std::collections::HashMap;
-use std::error::Error;
 use std::fmt::Write;
 use std::str::FromStr;
 
-use aoc::err;
+use anyhow::{anyhow, bail, Context, Result};
-use aoc::Result;
 
 const INPUT: &str = include_str!("../input/day04.txt");
 
@@ -30,7 +28,7 @@ enum Event {
 }
 
 impl FromStr for Event {
-    type Err = Box<dyn Error>;
+    type Err = anyhow::Error;
 
     fn from_str(s: &str) -> Result<Self> {
         if s.find("wakes up").is_some() {
@@ -38,13 +36,13 @@ impl FromStr for Event {
         } else if s.find("falls asleep").is_some() {
             Ok(Event::FallAsleep)
         } else if s.find("begins shift").is_some() {
-            let pound = s.find('#').ok_or_else(|| err!("`#` not found"))?;
+            let pound = s.find('#').context("`#` not found")?;
             let s = &s[(pound + 1)..];
-            let space = s.find(' ').ok_or_else(|| err!("` ` not found after `#`"))?;
+            let space = s.find(' ').context("` ` not found after `#`")?;
             let id = s[..space].parse()?;
             Ok(Event::ShiftChange(id))
         } else {
-            Err(err!("unknown event type"))
+            Err(anyhow!("unknown event type"))
         }
     }
 }
@@ -60,28 +58,28 @@ struct Date {
 }
 
 impl FromStr for Date {
-    type Err = Box<dyn Error>;
+    type Err = anyhow::Error;
 
     fn from_str(s: &str) -> Result<Self> {
-        let lbracket = s.find('[').ok_or_else(|| err!("`[` not found"))?;
+        let lbracket = s.find('[').context("`[` not found")?;
         let s = &s[(lbracket + 1)..];
-        let dash = s.find('-').ok_or_else(|| err!("`-` not found"))?;
+        let dash = s.find('-').context("`-` not found")?;
 
         let year = s[..dash].parse()?;
         let s = &s[(dash + 1)..];
-        let dash = s.find('-').ok_or_else(|| err!("`-` not found"))?;
+        let dash = s.find('-').context("`-` not found")?;
 
         let month = s[..dash].parse()?;
         let s = &s[(dash + 1)..];
-        let space = s.find(' ').ok_or_else(|| err!("` ` not found"))?;
+        let space = s.find(' ').context("` ` not found")?;
 
         let day = s[..space].parse()?;
         let s = &s[(space + 1)..];
-        let colon = s.find(':').ok_or_else(|| err!("`:` not found"))?;
+        let colon = s.find(':').context("`:` not found")?;
 
         let hour = s[..colon].parse()?;
         let s = &s[(colon + 1)..];
-        let rbracket = s.find(']').ok_or_else(|| err!("`]` not found"))?;
+        let rbracket = s.find(']').context("`]` not found")?;
 
         let minute = s[..rbracket].parse()?;
 
@@ -102,11 +100,11 @@ struct LogEntry {
 }
 
 impl FromStr for LogEntry {
-    type Err = Box<dyn Error>;
+    type Err = anyhow::Error;
 
     fn from_str(s: &str) -> Result<Self> {
-        let date: Date = s.parse().map_err(|e| err!("couldn't parse date: {}", e))?;
+        let date: Date = s.parse().context("couldn't parse date")?;
-        let event = s.parse().map_err(|e| err!("couldn't parse event: {}", e))?;
+        let event = s.parse().context("couldn't parse event")?;
 
         let entry = LogEntry { date, event };
 
@@ -134,7 +132,7 @@ fn part1(input: &str) -> Result<u64> {
 
         match guard_id {
             Some(id) => map.entry(id).or_default().push(log_entry),
-            None => return Err(err!("event before first shift")),
+            None => bail!("event before first shift"),
         }
     }
 
@@ -157,13 +155,13 @@ fn part1(input: &str) -> Result<u64> {
                         }
                         fell_asleep = None;
                     }
-                    None => return Err(err!("woke up before falling asleep")),
+                    None => bail!("woke up before falling asleep"),
                 },
             }
         }
 
         if fell_asleep.is_some() {
-            return Err(err!("fell asleep but never woke up!"));
+            bail!("fell asleep but never woke up!");
         }
 
         sleep_freq_per_guard.insert(id, sleep_freq);

aoc2018/src/day05.rs

@@ -1,7 +1,7 @@
 use std::collections::HashSet;
 use std::fmt::Write;
 
-use aoc::Result;
+use anyhow::Result;
 
 const INPUT: &str = include_str!("../input/day05.txt");
 

aoc2018/src/main.rs

@@ -1,5 +1,6 @@
+use anyhow::Result;
+
 use aoc::DayFunc;
-use aoc::Result;
 
 use aoc2018::day01;
 use aoc2018::day02;