From d91165207f12dfb5b64fab80a9fe2e2bc82670b2 Mon Sep 17 00:00:00 2001
From: Antoine Martin <antoine97.martin@gmail.com>
Date: Mon, 14 Dec 2020 18:08:16 +0100
Subject: [PATCH] 2020: switch to anyhow

---
 Cargo.lock           |  3 +++
 aoc/Cargo.toml       |  1 +
 aoc/src/lib.rs       | 14 +++-------
 aoc2020/src/day01.rs | 12 ++++-----
 aoc2020/src/day02.rs | 18 ++++++-------
 aoc2020/src/day03.rs | 12 +++++----
 aoc2020/src/day04.rs | 14 +++++-----
 aoc2020/src/day05.rs | 26 +++++++++----------
 aoc2020/src/day06.rs | 10 +++++---
 aoc2020/src/day07.rs | 20 +++++++--------
 aoc2020/src/day08.rs | 26 +++++++++----------
 aoc2020/src/day09.rs | 26 +++++++++----------
 aoc2020/src/day10.rs | 26 ++++++++-----------
 aoc2020/src/day11.rs | 16 ++++++------
 aoc2020/src/day12.rs | 24 ++++++++---------
 aoc2020/src/day13.rs | 28 ++++++++++----------
 aoc2020/src/day14.rs | 61 ++++++++++++++++++--------------------------
 aoc2020/src/main.rs  |  3 ++-
 18 files changed, 161 insertions(+), 179 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index 4181c25..e8b1e67 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -9,6 +9,9 @@ checksum = "2c0df63cb2955042487fad3aefd2c6e3ae7389ac5dc1beb28921de0b69f779d4"
 [[package]]
 name = "aoc"
 version = "0.1.0"
+dependencies = [
+ "anyhow",
+]
 
 [[package]]
 name = "aoc2015"
diff --git a/aoc/Cargo.toml b/aoc/Cargo.toml
index 7a169c1..5387799 100644
--- a/aoc/Cargo.toml
+++ b/aoc/Cargo.toml
@@ -7,3 +7,4 @@ edition = "2018"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
+anyhow = "1.0"
diff --git a/aoc/src/lib.rs b/aoc/src/lib.rs
index beab3ae..e5ac9c9 100644
--- a/aoc/src/lib.rs
+++ b/aoc/src/lib.rs
@@ -1,12 +1,6 @@
 use std::env;
 
-pub type Error = Box<dyn std::error::Error>;
-pub type Result<T> = std::result::Result<T, Error>;
-
-#[macro_export]
-macro_rules! err {
-    ($($string:expr),+) => (Box::<dyn std::error::Error>::from(format!($($string),+)))
-}
+use anyhow::{Context, Result};
 
 pub type DayFunc = fn() -> Result<String>;
 
@@ -16,15 +10,15 @@ pub fn run(days: &[DayFunc]) -> Result<()> {
 
     match args.next() {
         Some(arg) => {
-            let day: usize = arg.parse().expect("Please provide a day number");
-            let res = days[day - 1]().map_err(|e| err!("error running day specified: {}", e))?;
+            let day: usize = arg.parse().context("couldn't parse day number")?;
+            let res = days[day - 1]().context("error running day specified")?;
             println!("{}", res);
         }
         None => {
             for (i, day) in days.iter().enumerate() {
                 let i = i + 1;
                 println!("day{}: ", i);
-                let res = day().map_err(|e| err!("error running day {}: {}", i, e))?;
+                let res = day().with_context(|| format!("error running day {}", i))?;
                 println!("{}", res);
             }
         }
diff --git a/aoc2020/src/day01.rs b/aoc2020/src/day01.rs
index 2ce70d1..cd5220f 100644
--- a/aoc2020/src/day01.rs
+++ b/aoc2020/src/day01.rs
@@ -1,7 +1,7 @@
 use std::collections::HashSet;
 use std::fmt::Write;
 
-use aoc::{err, Result};
+use anyhow::{anyhow, Result};
 
 const INPUT: &str = include_str!("../input/day01.txt");
 
@@ -17,7 +17,7 @@ pub fn run() -> Result<String> {
 fn part1(input: &str) -> Result<i64> {
     let entries = input
         .lines()
-        .map(|line| line.parse::<i64>().map_err(|e| err!("{}", e)))
+        .map(|line| line.parse::<i64>().map_err(anyhow::Error::new))
         .collect::<Result<Vec<i64>>>()?;
 
     let (a, b) = find_2020_2_sum(&entries)?;
@@ -28,8 +28,8 @@ fn part1(input: &str) -> Result<i64> {
 fn part2(input: &str) -> Result<i64> {
     let entries = input
         .lines()
-        .map(|line| line.parse::<i64>().map_err(|e| err!("{}", e)))
-        .collect::<Result<Vec<i64>>>()?;
+        .map(|line| line.parse::<i64>().map_err(anyhow::Error::new))
+        .collect::<Result<Vec<_>>>()?;
 
     let (a, b, c) = find_2020_3_sum(&entries)?;
 
@@ -47,7 +47,7 @@ fn find_2020_2_sum(entries: &[i64]) -> Result<(i64, i64)> {
         }
     }
 
-    Err(err!("couldn't find 2 elements that sum to 2020"))
+    Err(anyhow!("couldn't find 2 elements that sum to 2020"))
 }
 
 fn find_2020_3_sum(entries: &[i64]) -> Result<(i64, i64, i64)> {
@@ -70,7 +70,7 @@ fn find_2020_3_sum(entries: &[i64]) -> Result<(i64, i64, i64)> {
         }
     }
 
-    Err(err!("couldn't find 2 elements that sum to 2020"))
+    Err(anyhow!("couldn't find 2 elements that sum to 2020"))
 }
 
 #[cfg(test)]
diff --git a/aoc2020/src/day02.rs b/aoc2020/src/day02.rs
index 47b1f51..66696f5 100644
--- a/aoc2020/src/day02.rs
+++ b/aoc2020/src/day02.rs
@@ -1,7 +1,7 @@
 use std::fmt::Write;
 use std::str::FromStr;
 
-use aoc::{err, Result};
+use anyhow::{Context, Result};
 
 const INPUT: &str = include_str!("../input/day02.txt");
 
@@ -44,28 +44,28 @@ impl PassPolicy {
 }
 
 impl FromStr for PassPolicy {
-    type Err = aoc::Error;
+    type Err = anyhow::Error;
 
     fn from_str(s: &str) -> Result<Self> {
         let s = s.trim_end();
 
         let space = s
             .find(' ')
-            .ok_or_else(|| err!("couldn't parse password policy: didn't find space"))?;
+            .context("couldn't parse password policy: didn't find space")?;
         let dash = s
             .find('-')
-            .ok_or_else(|| err!("couldn't parse password policy: didn't find dash"))?;
+            .context("couldn't parse password policy: didn't find dash")?;
 
         let min_bound = s[..dash]
             .parse::<usize>()
-            .map_err(|e| err!("couldn't  parse range: {}", e))?;
+            .context("couldn't  parse range")?;
         let max_bound = s[(dash + 1)..space]
             .parse::<usize>()
-            .map_err(|e| err!("couldn't parse range: {}", e))?;
+            .context("couldn't parse range")?;
 
         let colon = s
             .find(':')
-            .ok_or_else(|| err!("couldn't parse password policy: didn't find colon"))?;
+            .context("couldn't parse password policy: didn't find colon")?;
 
         let letter = s.as_bytes()[colon - 1];
 
@@ -92,7 +92,7 @@ pub fn run() -> Result<String> {
 fn part1(input: &str) -> Result<usize> {
     let policies = input
         .lines()
-        .map(|line| line.parse::<PassPolicy>().map_err(|e| err!("{}", e)))
+        .map(|line| line.parse::<PassPolicy>())
         .collect::<Result<Vec<PassPolicy>>>()?;
 
     Ok(policies
@@ -104,7 +104,7 @@ fn part1(input: &str) -> Result<usize> {
 fn part2(input: &str) -> Result<usize> {
     let policies = input
         .lines()
-        .map(|line| line.parse::<PassPolicy>().map_err(|e| err!("{}", e)))
+        .map(|line| line.parse::<PassPolicy>())
         .collect::<Result<Vec<PassPolicy>>>()?;
 
     Ok(policies
diff --git a/aoc2020/src/day03.rs b/aoc2020/src/day03.rs
index 28e8232..326a62f 100644
--- a/aoc2020/src/day03.rs
+++ b/aoc2020/src/day03.rs
@@ -3,9 +3,11 @@ use std::iter::FromIterator;
 use std::ops::Index;
 use std::str::FromStr;
 
+use anyhow::Result;
+
 const INPUT: &str = include_str!("../input/day03.txt");
 
-pub fn run() -> aoc::Result<String> {
+pub fn run() -> Result<String> {
     let mut res = String::with_capacity(128);
 
     writeln!(res, "part 1: {}", part1(INPUT)?)?;
@@ -14,13 +16,13 @@ pub fn run() -> aoc::Result<String> {
     Ok(res)
 }
 
-fn part1(input: &str) -> aoc::Result<usize> {
+fn part1(input: &str) -> Result<usize> {
     let forest = input.parse()?;
 
     Ok(count_trees(&forest, (3, 1)))
 }
 
-fn part2(input: &str) -> aoc::Result<usize> {
+fn part2(input: &str) -> Result<usize> {
     let forest = input.parse()?;
 
     let slopes = &[(1, 1), (3, 1), (5, 1), (7, 1), (1, 2)];
@@ -89,9 +91,9 @@ impl Index<usize> for Forest {
 }
 
 impl FromStr for Forest {
-    type Err = aoc::Error;
+    type Err = anyhow::Error;
 
-    fn from_str(s: &str) -> aoc::Result<Self> {
+    fn from_str(s: &str) -> Result<Self> {
         let trees = s
             .lines()
             .map(|line| line.chars().map(|c| matches!(c, '#')).collect())
diff --git a/aoc2020/src/day04.rs b/aoc2020/src/day04.rs
index 569d222..3cc5cc5 100644
--- a/aoc2020/src/day04.rs
+++ b/aoc2020/src/day04.rs
@@ -3,9 +3,11 @@ use std::fmt::Write;
 use std::ops::RangeInclusive;
 use std::str::FromStr;
 
+use anyhow::Result;
+
 const INPUT: &str = include_str!("../input/day04.txt");
 
-pub fn run() -> aoc::Result<String> {
+pub fn run() -> Result<String> {
     let mut res = String::with_capacity(128);
 
     writeln!(res, "part 1: {}", part1(INPUT)?)?;
@@ -14,7 +16,7 @@ pub fn run() -> aoc::Result<String> {
     Ok(res)
 }
 
-fn get_passports(input: &str) -> aoc::Result<Vec<Passport>> {
+fn get_passports(input: &str) -> Result<Vec<Passport>> {
     let mut passports: Vec<Passport> = Vec::new();
 
     let mut passport = String::new();
@@ -35,13 +37,13 @@ fn get_passports(input: &str) -> aoc::Result<Vec<Passport>> {
     Ok(passports)
 }
 
-fn part1(input: &str) -> aoc::Result<usize> {
+fn part1(input: &str) -> Result<usize> {
     let passports = get_passports(input)?;
 
     Ok(passports.iter().filter(|p| p.is_complete()).count())
 }
 
-fn part2(input: &str) -> aoc::Result<usize> {
+fn part2(input: &str) -> Result<usize> {
     let passports = get_passports(input)?;
 
     Ok(passports
@@ -89,9 +91,9 @@ impl Passport {
 }
 
 impl FromStr for Passport {
-    type Err = aoc::Error;
+    type Err = anyhow::Error;
 
-    fn from_str(s: &str) -> aoc::Result<Self> {
+    fn from_str(s: &str) -> Result<Self> {
         let mut fields: HashMap<&str, String> = s
             .split_whitespace()
             .map(|f| {
diff --git a/aoc2020/src/day05.rs b/aoc2020/src/day05.rs
index 4cf1866..198f084 100644
--- a/aoc2020/src/day05.rs
+++ b/aoc2020/src/day05.rs
@@ -1,11 +1,11 @@
 use std::fmt::Write;
 use std::str::FromStr;
 
-use aoc::err;
+use anyhow::{anyhow, bail, Context, Result};
 
 const INPUT: &str = include_str!("../input/day05.txt");
 
-pub fn run() -> aoc::Result<String> {
+pub fn run() -> Result<String> {
     let mut res = String::with_capacity(128);
 
     writeln!(res, "part 1: {}", part1(INPUT)?)?;
@@ -14,26 +14,24 @@ pub fn run() -> aoc::Result<String> {
     Ok(res)
 }
 
-fn part1(input: &str) -> aoc::Result<usize> {
+fn part1(input: &str) -> Result<usize> {
     let seats = input
         .lines()
         .map(|line| line.parse())
-        .collect::<aoc::Result<Vec<Seat>>>()
-        .map_err(|e| err!("{}", e))?;
+        .collect::<Result<Vec<Seat>>>()?;
 
     seats
         .iter()
         .map(|seat| seat.id())
         .max()
-        .ok_or_else(|| err!("0 seats processed"))
+        .context("0 seats processed")
 }
 
-fn part2(input: &str) -> aoc::Result<usize> {
+fn part2(input: &str) -> Result<usize> {
     let mut seats = input
         .lines()
         .map(|line| line.parse())
-        .collect::<aoc::Result<Vec<Seat>>>()
-        .map_err(|e| err!("{}", e))?;
+        .collect::<Result<Vec<Seat>>>()?;
 
     // Seats will be sorted by lexicographical order of fields thanks to `derive(PartialOrd, Ord)`,
     // which should produce the same result as a manual implementation of `Ord` and `PartialOrd`
@@ -49,7 +47,7 @@ fn part2(input: &str) -> aoc::Result<usize> {
         }
     }
 
-    Err(err!("didn't find missing seat"))
+    Err(anyhow!("didn't find missing seat"))
 }
 
 #[derive(Debug, PartialEq, Eq, PartialOrd, Ord)]
@@ -65,11 +63,11 @@ impl Seat {
 }
 
 impl FromStr for Seat {
-    type Err = aoc::Error;
+    type Err = anyhow::Error;
 
-    fn from_str(s: &str) -> aoc::Result<Self> {
+    fn from_str(s: &str) -> Result<Self> {
         if s.len() != 10 {
-            return Err(err!("Seat encoding must be 10 chars long: {}", s));
+            bail!("Seat encoding must be 10 chars long: {}", s);
         }
 
         let (mut row_begin, mut row_end) = (0, 128);
@@ -90,7 +88,7 @@ impl FromStr for Seat {
                 'R' => {
                     col_begin += col_range;
                 }
-                _ => return Err(err!("Wrong char while decoding seat: `{}`", c)),
+                _ => bail!("Wrong char while decoding seat: `{}`", c),
             }
         }
 
diff --git a/aoc2020/src/day06.rs b/aoc2020/src/day06.rs
index c7db5a5..810f75b 100644
--- a/aoc2020/src/day06.rs
+++ b/aoc2020/src/day06.rs
@@ -1,9 +1,11 @@
 use std::collections::HashSet;
 use std::fmt::Write;
 
+use anyhow::Result;
+
 const INPUT: &str = include_str!("../input/day06.txt");
 
-pub fn run() -> aoc::Result<String> {
+pub fn run() -> Result<String> {
     let mut res = String::with_capacity(128);
 
     writeln!(res, "part 1: {}", part1(INPUT)?)?;
@@ -12,7 +14,7 @@ pub fn run() -> aoc::Result<String> {
     Ok(res)
 }
 
-fn get_groups(input: &str) -> aoc::Result<Vec<Group>> {
+fn get_groups(input: &str) -> Result<Vec<Group>> {
     let mut groups = Vec::new();
 
     let mut answers = Vec::new();
@@ -36,7 +38,7 @@ fn get_groups(input: &str) -> aoc::Result<Vec<Group>> {
     Ok(groups)
 }
 
-fn part1(input: &str) -> aoc::Result<usize> {
+fn part1(input: &str) -> Result<usize> {
     let groups = get_groups(input)?;
 
     Ok(groups
@@ -45,7 +47,7 @@ fn part1(input: &str) -> aoc::Result<usize> {
         .sum())
 }
 
-fn part2(input: &str) -> aoc::Result<usize> {
+fn part2(input: &str) -> Result<usize> {
     let groups = get_groups(input)?;
 
     Ok(groups
diff --git a/aoc2020/src/day07.rs b/aoc2020/src/day07.rs
index 37fd9d4..bc13f81 100644
--- a/aoc2020/src/day07.rs
+++ b/aoc2020/src/day07.rs
@@ -2,11 +2,11 @@ use std::collections::HashMap;
 use std::fmt::Write;
 use std::str::FromStr;
 
-use aoc::err;
+use anyhow::{Context, Result};
 
 const INPUT: &str = include_str!("../input/day07.txt");
 
-pub fn run() -> aoc::Result<String> {
+pub fn run() -> Result<String> {
     let mut res = String::with_capacity(128);
 
     writeln!(res, "part 1: {}", part1(INPUT)?)?;
@@ -15,11 +15,11 @@ pub fn run() -> aoc::Result<String> {
     Ok(res)
 }
 
-fn part1(input: &str) -> aoc::Result<usize> {
+fn part1(input: &str) -> Result<usize> {
     let bag_rules = input
         .lines()
         .map(|line| line.parse())
-        .collect::<aoc::Result<Vec<BagRule>>>()
+        .collect::<Result<Vec<BagRule>>>()
         .unwrap();
 
     // create map with Key = color, Value = BagRule
@@ -39,11 +39,11 @@ fn part1(input: &str) -> aoc::Result<usize> {
         .count())
 }
 
-fn part2(input: &str) -> aoc::Result<usize> {
+fn part2(input: &str) -> Result<usize> {
     let bag_rules = input
         .lines()
         .map(|line| line.parse())
-        .collect::<aoc::Result<Vec<BagRule>>>()
+        .collect::<Result<Vec<BagRule>>>()
         .unwrap();
 
     // create map with Key = color, Value = BagRule
@@ -102,9 +102,9 @@ impl BagRule {
 }
 
 impl FromStr for BagRule {
-    type Err = aoc::Error;
+    type Err = anyhow::Error;
 
-    fn from_str(s: &str) -> aoc::Result<Self> {
+    fn from_str(s: &str) -> Result<Self> {
         let words: Vec<&str> = s.split(' ').collect();
 
         // let's assume our input is always valid for now
@@ -130,7 +130,7 @@ impl FromStr for BagRule {
                 number => {
                     let n = number
                         .parse()
-                        .map_err(|e| err!("couldn't parse number `{}` in bag rule", e))?;
+                        .context("couldn't parse number in bag rule")?;
 
                     let adjective = words[1];
                     let color = words[2];
@@ -169,7 +169,7 @@ mod tests {
         let bag_rules = PROVIDED1
             .lines()
             .map(|line| line.parse())
-            .collect::<aoc::Result<Vec<BagRule>>>()
+            .collect::<Result<Vec<BagRule>>>()
             .unwrap();
 
         let expected = vec![
diff --git a/aoc2020/src/day08.rs b/aoc2020/src/day08.rs
index e1c2c96..6e057b9 100644
--- a/aoc2020/src/day08.rs
+++ b/aoc2020/src/day08.rs
@@ -1,11 +1,11 @@
 use std::collections::HashSet;
 use std::fmt::Write;
 
-use aoc::err;
+use anyhow::{anyhow, bail, Context, Result};
 
 const INPUT: &str = include_str!("../input/day08.txt");
 
-pub fn run() -> aoc::Result<String> {
+pub fn run() -> Result<String> {
     let mut res = String::with_capacity(128);
 
     writeln!(res, "part 1: {}", part1(INPUT)?)?;
@@ -14,25 +14,25 @@ pub fn run() -> aoc::Result<String> {
     Ok(res)
 }
 
-fn part1(input: &str) -> aoc::Result<i64> {
+fn part1(input: &str) -> Result<i64> {
     let instructions = input
         .lines()
         .map(|line| line.parse())
-        .collect::<aoc::Result<Vec<Instruction>>>()?;
+        .collect::<Result<Vec<Instruction>>>()?;
 
     let mut interpreter = Interpreter::new(instructions);
 
     Ok(match interpreter.run() {
         ExitStatus::InfiniteLoop(value) => value,
-        ExitStatus::End(_) => return Err(err!("interpreter doesn't have an infinite loop")),
+        ExitStatus::End(_) => bail!("interpreter doesn't have an infinite loop"),
     })
 }
 
-fn part2(input: &str) -> aoc::Result<i64> {
+fn part2(input: &str) -> Result<i64> {
     let instructions = input
         .lines()
         .map(|line| line.parse())
-        .collect::<aoc::Result<Vec<Instruction>>>()?;
+        .collect::<Result<Vec<Instruction>>>()?;
 
     for idx in 0..instructions.len() {
         let mut instructions = instructions.clone();
@@ -51,7 +51,7 @@ fn part2(input: &str) -> aoc::Result<i64> {
         }
     }
 
-    Err(err!(
+    Err(anyhow!(
         "interpreter always had an infinite loop, no solution found"
     ))
 }
@@ -110,21 +110,21 @@ enum Instruction {
 }
 
 impl std::str::FromStr for Instruction {
-    type Err = aoc::Error;
+    type Err = anyhow::Error;
 
-    fn from_str(s: &str) -> aoc::Result<Self> {
-        let space = s.find(' ').ok_or_else(|| err!("couldn't split on space"))?;
+    fn from_str(s: &str) -> Result<Self> {
+        let space = s.find(' ').context("couldn't split on space")?;
 
         let inst = &s[..space];
         let arg = s[(space + 1)..]
             .parse()
-            .map_err(|e| err!("couldn't parse argument for instruction: {}", e))?;
+            .context("couldn't parse argument for instruction")?;
 
         Ok(match inst {
             "acc" => Self::Acc(arg),
             "jmp" => Self::Jmp(arg),
             "nop" => Self::Nop(arg),
-            _ => return Err(err!("unrecognized instruction `{}`", inst)),
+            _ => bail!("unrecognized instruction `{}`", inst),
         })
     }
 }
diff --git a/aoc2020/src/day09.rs b/aoc2020/src/day09.rs
index e203d42..f3dafc8 100644
--- a/aoc2020/src/day09.rs
+++ b/aoc2020/src/day09.rs
@@ -1,10 +1,10 @@
 use std::fmt::Write;
 
-use aoc::err;
+use anyhow::{anyhow, Result};
 
 const INPUT: &str = include_str!("../input/day09.txt");
 
-pub fn run() -> aoc::Result<String> {
+pub fn run() -> Result<String> {
     let mut res = String::with_capacity(128);
 
     writeln!(res, "part 1: {}", part1(INPUT)?)?;
@@ -27,7 +27,7 @@ fn find_pair_sum(data: &[u64], total: u64) -> Option<(u64, u64)> {
     None
 }
 
-fn find_outlier(numbers: &[u64], preamble_size: usize) -> aoc::Result<(u64, usize)> {
+fn find_outlier(numbers: &[u64], preamble_size: usize) -> Result<(u64, usize)> {
     // start checking numbers after the preamble only
     for i in preamble_size..numbers.len() {
         let preamble = &numbers[(i - preamble_size)..i];
@@ -39,22 +39,21 @@ fn find_outlier(numbers: &[u64], preamble_size: usize) -> aoc::Result<(u64, usiz
         }
     }
 
-    Err(err!("couldn't find number with that property"))
+    Err(anyhow!("couldn't find number with that property"))
 }
 
-fn part1(input: &str) -> aoc::Result<u64> {
+fn part1(input: &str) -> Result<u64> {
     let numbers = input
         .lines()
-        .map(|line| line.parse::<u64>())
-        .collect::<Result<Vec<u64>, _>>()
-        .map_err(|e| err!("couldn't parse number: {}", e))?;
+        .map(|line| line.parse::<u64>().map_err(anyhow::Error::new))
+        .collect::<Result<Vec<u64>, _>>()?;
 
     let (solution, _) = find_outlier(&numbers, 25)?;
 
     Ok(solution)
 }
 
-fn find_contiguous_range(numbers: &[u64], total: u64) -> aoc::Result<(u64, u64)> {
+fn find_contiguous_range(numbers: &[u64], total: u64) -> Result<(u64, u64)> {
     // compute cumulated sums for the whole range
     let (sums, _) = numbers.iter().fold((vec![0], 0), |(mut vec, acc), n| {
         let acc = acc + n;
@@ -74,15 +73,14 @@ fn find_contiguous_range(numbers: &[u64], total: u64) -> aoc::Result<(u64, u64)>
         }
     }
 
-    Err(err!("couldn't find number with that property"))
+    Err(anyhow!("couldn't find number with that property"))
 }
 
-fn part2(input: &str) -> aoc::Result<u64> {
+fn part2(input: &str) -> Result<u64> {
     let numbers = input
         .lines()
-        .map(|line| line.parse::<u64>())
-        .collect::<Result<Vec<u64>, _>>()
-        .map_err(|e| err!("couldn't parse number: {}", e))?;
+        .map(|line| line.parse::<u64>().map_err(anyhow::Error::new))
+        .collect::<Result<Vec<u64>, _>>()?;
 
     let (outlier, idx) = find_outlier(&numbers, 25)?;
 
diff --git a/aoc2020/src/day10.rs b/aoc2020/src/day10.rs
index 95eae68..9336a02 100644
--- a/aoc2020/src/day10.rs
+++ b/aoc2020/src/day10.rs
@@ -1,11 +1,11 @@
 use std::collections::HashMap;
 use std::fmt::Write;
 
-use aoc::err;
+use anyhow::{bail, Result};
 
 const INPUT: &str = include_str!("../input/day10.txt");
 
-pub fn run() -> aoc::Result<String> {
+pub fn run() -> Result<String> {
     let mut res = String::with_capacity(128);
 
     writeln!(res, "part 1: {}", part1(INPUT)?)?;
@@ -14,17 +14,14 @@ pub fn run() -> aoc::Result<String> {
     Ok(res)
 }
 
-fn part1(input: &str) -> aoc::Result<usize> {
+fn part1(input: &str) -> Result<usize> {
     let mut jolts = input
         .lines()
-        .map(|line| {
-            line.parse()
-                .map_err(|e| err!("couldn't parse joltage: {}", e))
-        })
-        .collect::<aoc::Result<Vec<u64>>>()?;
+        .map(|line| line.parse().map_err(anyhow::Error::new))
+        .collect::<Result<Vec<u64>>>()?;
 
     if jolts.is_empty() {
-        return Err(err!("input was empty!"));
+        bail!("input was empty!");
     }
 
     // charging outlet can be added
@@ -80,17 +77,14 @@ fn find_possibilities(jolts: &[u64], possibilities: &mut HashMap<u64, usize>) ->
     possibilities_from_here
 }
 
-fn part2(input: &str) -> aoc::Result<usize> {
+fn part2(input: &str) -> Result<usize> {
     let mut jolts = input
         .lines()
-        .map(|line| {
-            line.parse()
-                .map_err(|e| err!("couldn't parse joltage: {}", e))
-        })
-        .collect::<aoc::Result<Vec<u64>>>()?;
+        .map(|line| line.parse().map_err(anyhow::Error::new))
+        .collect::<Result<Vec<u64>>>()?;
 
     if jolts.is_empty() {
-        return Err(err!("input was empty!"));
+        bail!("input was empty!");
     }
 
     // charging outlet can be added
diff --git a/aoc2020/src/day11.rs b/aoc2020/src/day11.rs
index af8a480..5f5c9dd 100644
--- a/aoc2020/src/day11.rs
+++ b/aoc2020/src/day11.rs
@@ -1,10 +1,10 @@
 use std::fmt::Write;
 
-use aoc::err;
+use anyhow::{anyhow, Result};
 
 const INPUT: &str = include_str!("../input/day11.txt");
 
-pub fn run() -> aoc::Result<String> {
+pub fn run() -> Result<String> {
     let mut res = String::with_capacity(128);
 
     writeln!(res, "part 1: {}", part1(INPUT)?)?;
@@ -13,7 +13,7 @@ pub fn run() -> aoc::Result<String> {
     Ok(res)
 }
 
-fn part1(input: &str) -> aoc::Result<usize> {
+fn part1(input: &str) -> Result<usize> {
     let mut layout: Layout = input.parse()?;
 
     let occupied_threshold = 4;
@@ -22,7 +22,7 @@ fn part1(input: &str) -> aoc::Result<usize> {
     Ok(layout.occupied_seats())
 }
 
-fn part2(input: &str) -> aoc::Result<usize> {
+fn part2(input: &str) -> Result<usize> {
     let mut layout: Layout = input.parse()?;
 
     let occupied_threshold = 5;
@@ -177,9 +177,9 @@ impl std::ops::IndexMut<usize> for Layout {
 }
 
 impl std::str::FromStr for Layout {
-    type Err = aoc::Error;
+    type Err = anyhow::Error;
 
-    fn from_str(s: &str) -> aoc::Result<Self> {
+    fn from_str(s: &str) -> Result<Self> {
         let grid = s
             .lines()
             .map(|line| {
@@ -188,11 +188,11 @@ impl std::str::FromStr for Layout {
                         '.' => Ok(Cell::Floor),
                         'L' => Ok(Cell::EmptySeat),
                         '#' => Ok(Cell::OccupiedSeat),
-                        _ => Err(err!("unknown char `{}`", c)),
+                        _ => Err(anyhow!("unknown char `{}`", c)),
                     })
                     .collect()
             })
-            .collect::<aoc::Result<Grid>>()?;
+            .collect::<Result<Grid>>()?;
 
         let height = grid.len();
         let width = grid[0].len();
diff --git a/aoc2020/src/day12.rs b/aoc2020/src/day12.rs
index ee1aa46..5470292 100644
--- a/aoc2020/src/day12.rs
+++ b/aoc2020/src/day12.rs
@@ -1,10 +1,10 @@
 use std::fmt::Write;
 
-use aoc::err;
+use anyhow::{bail, Context, Result};
 
 const INPUT: &str = include_str!("../input/day12.txt");
 
-pub fn run() -> aoc::Result<String> {
+pub fn run() -> Result<String> {
     let mut res = String::with_capacity(128);
 
     writeln!(res, "part 1: {}", part1(INPUT)?)?;
@@ -13,11 +13,11 @@ pub fn run() -> aoc::Result<String> {
     Ok(res)
 }
 
-fn part1(input: &str) -> aoc::Result<i64> {
+fn part1(input: &str) -> Result<i64> {
     let actions: Vec<Action> = input
         .lines()
         .map(|line| line.parse())
-        .collect::<aoc::Result<_>>()?;
+        .collect::<Result<_>>()?;
 
     let mut ship = Ship::new();
 
@@ -28,11 +28,11 @@ fn part1(input: &str) -> aoc::Result<i64> {
     Ok(ship.manhattan_distance())
 }
 
-fn part2(input: &str) -> aoc::Result<i64> {
+fn part2(input: &str) -> Result<i64> {
     let actions: Vec<Action> = input
         .lines()
         .map(|line| line.parse())
-        .collect::<aoc::Result<_>>()?;
+        .collect::<Result<_>>()?;
 
     let mut ship = Ship::new();
 
@@ -118,9 +118,9 @@ struct Action {
 }
 
 impl std::str::FromStr for Action {
-    type Err = aoc::Error;
+    type Err = anyhow::Error;
 
-    fn from_str(s: &str) -> aoc::Result<Self> {
+    fn from_str(s: &str) -> Result<Self> {
         debug_assert!(
             s.len() >= 2,
             "tried to parse action but it is too short: `{}`",
@@ -129,7 +129,7 @@ impl std::str::FromStr for Action {
         let letter = s
             .chars()
             .next()
-            .ok_or_else(|| err!("couldn't parse action: empty string"))?;
+            .context("couldn't parse action: empty string")?;
 
         let kind = match letter {
             'N' => ActionKind::Move(Direction::North),
@@ -142,12 +142,10 @@ impl std::str::FromStr for Action {
 
             'F' => ActionKind::Forward,
 
-            _ => return Err(err!("couldn't parse action with letter `{}`", letter)),
+            _ => bail!("couldn't parse action with letter `{}`", letter),
         };
 
-        let arg = s[1..]
-            .parse()
-            .map_err(|e| err!("couldn't parse action arg: {}", e))?;
+        let arg = s[1..].parse().context("couldn't parse action arg")?;
 
         Ok(Self { kind, arg })
     }
diff --git a/aoc2020/src/day13.rs b/aoc2020/src/day13.rs
index 0175df9..5fe9974 100644
--- a/aoc2020/src/day13.rs
+++ b/aoc2020/src/day13.rs
@@ -1,10 +1,10 @@
 use std::fmt::Write;
 
-use aoc::err;
+use anyhow::{Context, Result};
 
 const INPUT: &str = include_str!("../input/day13.txt");
 
-pub fn run() -> aoc::Result<String> {
+pub fn run() -> Result<String> {
     let mut res = String::with_capacity(128);
 
     writeln!(res, "part 1: {}", part1(INPUT)?)?;
@@ -13,27 +13,27 @@ pub fn run() -> aoc::Result<String> {
     Ok(res)
 }
 
-fn part1(input: &str) -> aoc::Result<u64> {
+fn part1(input: &str) -> Result<u64> {
     let mut lines = input.lines();
 
     let earliest_timestamp = lines
         .next()
-        .ok_or_else(|| err!("input was empty"))?
+        .context("input was empty")?
         .parse::<u64>()
-        .map_err(|e| err!("couldn't parse first line: {}", e))?;
+        .context("couldn't parse first line")?;
 
     let bus_ids = lines
         .next()
-        .ok_or_else(|| err!("no second line"))?
+        .context("no second line")?
         .split(',')
         .filter_map(|num| {
             if num == "x" {
                 None
             } else {
-                Some(num.parse::<u64>().map_err(|e| err!("{}", e)))
+                Some(num.parse::<u64>().map_err(anyhow::Error::new))
             }
         })
-        .collect::<aoc::Result<Vec<_>>>()?;
+        .collect::<Result<Vec<_>>>()?;
 
     let (bus_id, earliest_departure) = bus_ids
         .iter()
@@ -47,16 +47,16 @@ fn part1(input: &str) -> aoc::Result<u64> {
     Ok(bus_id * (earliest_departure - earliest_timestamp))
 }
 
-fn part2(input: &str) -> aoc::Result<u64> {
+fn part2(input: &str) -> Result<u64> {
     let mut lines = input.lines();
 
     // we don't need the first line anymore, skip it
-    lines.next().ok_or_else(|| err!("input was empty"))?;
+    lines.next().context("input was empty")?;
 
-    find_timestamp(lines.next().ok_or_else(|| err!("no second line"))?)
+    find_timestamp(lines.next().context("no second line")?)
 }
 
-fn find_timestamp(input: &str) -> aoc::Result<u64> {
+fn find_timestamp(input: &str) -> Result<u64> {
     let bus_ids: Vec<(u64, u64)> = input
         .split(',')
         .enumerate()
@@ -64,14 +64,14 @@ fn find_timestamp(input: &str) -> aoc::Result<u64> {
             if num == "x" {
                 None
             } else {
-                Some((idx as u64, num.parse::<u64>().map_err(|e| err!("{}", e))))
+                Some((idx as u64, num.parse::<u64>().map_err(anyhow::Error::new)))
             }
         })
         .map(|(idx, res)| match res {
             Ok(num) => Ok((idx, num)),
             Err(e) => Err(e),
         })
-        .collect::<aoc::Result<_>>()?;
+        .collect::<Result<_>>()?;
 
     // previous constraints is empty for now
     let mut current_solution = 0;
diff --git a/aoc2020/src/day14.rs b/aoc2020/src/day14.rs
index 8fe24f4..a2ef9b4 100644
--- a/aoc2020/src/day14.rs
+++ b/aoc2020/src/day14.rs
@@ -1,11 +1,11 @@
 use std::collections::HashMap;
 use std::fmt::Write;
 
-use aoc::err;
+use anyhow::{anyhow, bail, Context, Result};
 
 const INPUT: &str = include_str!("../input/day14.txt");
 
-pub fn run() -> aoc::Result<String> {
+pub fn run() -> Result<String> {
     let mut res = String::with_capacity(128);
 
     writeln!(res, "part 1: {}", part1(INPUT)?)?;
@@ -14,7 +14,7 @@ pub fn run() -> aoc::Result<String> {
     Ok(res)
 }
 
-fn part1(input: &str) -> aoc::Result<u64> {
+fn part1(input: &str) -> Result<u64> {
     let mut program: Program = input.parse()?;
 
     program.run_part1()?;
@@ -22,7 +22,7 @@ fn part1(input: &str) -> aoc::Result<u64> {
     Ok(program.memory_sum())
 }
 
-fn part2(input: &str) -> aoc::Result<u64> {
+fn part2(input: &str) -> Result<u64> {
     let mut program: Program = input.parse()?;
 
     program.run_part2()?;
@@ -175,9 +175,9 @@ impl BitMask {
 }
 
 impl std::str::FromStr for BitMask {
-    type Err = aoc::Error;
+    type Err = anyhow::Error;
 
-    fn from_str(s: &str) -> aoc::Result<Self> {
+    fn from_str(s: &str) -> Result<Self> {
         let masks = s
             .chars()
             .rev()
@@ -187,10 +187,10 @@ impl std::str::FromStr for BitMask {
                     '1' => Ok(Mask::One),
                     '0' => Ok(Mask::Zero),
                     'X' => Ok(Mask::Floating),
-                    _ => Err(err!("unknown character in mask: `{}`", c)),
+                    _ => Err(anyhow!("unknown character in mask: `{}`", c)),
                 }
             })
-            .collect::<aoc::Result<_>>()?;
+            .collect::<Result<_>>()?;
 
         Ok(BitMask { masks })
     }
@@ -203,23 +203,17 @@ enum Instruction {
 }
 
 impl std::str::FromStr for Instruction {
-    type Err = aoc::Error;
+    type Err = anyhow::Error;
 
-    fn from_str(s: &str) -> aoc::Result<Self> {
+    fn from_str(s: &str) -> Result<Self> {
         let mut words = s.split(' ');
 
-        let first = words
-            .next()
-            .ok_or_else(|| err!("missing first word in instruction"))?;
-        let second = words
-            .next()
-            .ok_or_else(|| err!("missing second word in instruction"))?;
-        let third = words
-            .next()
-            .ok_or_else(|| err!("missing third word in instruction"))?;
+        let first = words.next().context("missing first word in instruction")?;
+        let second = words.next().context("missing second word in instruction")?;
+        let third = words.next().context("missing third word in instruction")?;
 
         if second != "=" {
-            return Err(err!("expected `=` as second word in instruction: `{}`", s));
+            bail!("expected `=` as second word in instruction: `{}`", s);
         }
 
         if first == "mask" {
@@ -227,18 +221,16 @@ impl std::str::FromStr for Instruction {
         } else {
             let left_bracket = first
                 .find('[')
-                .ok_or_else(|| err!("couldn't find bracket in memory instruction"))?;
+                .context("couldn't find bracket in memory instruction")?;
             let right_bracket = first
                 .find(']')
-                .ok_or_else(|| err!("couldn't find bracket in memory instruction"))?;
+                .context("couldn't find bracket in memory instruction")?;
 
             let offset = first[(left_bracket + 1)..right_bracket]
                 .parse()
-                .map_err(|e| err!("couldn't parse memory offset: `{}`", e))?;
+                .context("couldn't parse memory offset")?;
 
-            let value = third
-                .parse()
-                .map_err(|e| err!("couldn't parse memory offset: `{}`", e))?;
+            let value = third.parse().context("couldn't parse memory offset")?;
 
             Ok(Self::MemWrite { offset, value })
         }
@@ -252,7 +244,7 @@ struct Program {
 }
 
 impl Program {
-    fn run_part1(&mut self) -> aoc::Result<()> {
+    fn run_part1(&mut self) -> Result<()> {
         for inst in &self.instructions {
             match inst {
                 Instruction::ChangeMask(bitmask) => self.current_mask = Some(bitmask.clone()),
@@ -263,7 +255,7 @@ impl Program {
                             .insert(*offset, bitmask.apply_no_floating(*value));
                     }
                     None => {
-                        return Err(err!("tried to execute MemWrite but mask isn't initialized"))
+                        bail!("tried to execute MemWrite but mask isn't initialized")
                     }
                 },
             }
@@ -272,7 +264,7 @@ impl Program {
         Ok(())
     }
 
-    fn run_part2(&mut self) -> aoc::Result<()> {
+    fn run_part2(&mut self) -> Result<()> {
         for inst in &self.instructions {
             match inst {
                 Instruction::ChangeMask(bitmask) => self.current_mask = Some(bitmask.clone()),
@@ -284,7 +276,7 @@ impl Program {
                         }
                     }
                     None => {
-                        return Err(err!("tried to execute MemWrite but mask isn't initialized"))
+                        bail!("tried to execute MemWrite but mask isn't initialized")
                     }
                 },
             }
@@ -299,13 +291,10 @@ impl Program {
 }
 
 impl std::str::FromStr for Program {
-    type Err = aoc::Error;
+    type Err = anyhow::Error;
 
-    fn from_str(s: &str) -> aoc::Result<Self> {
-        let instructions = s
-            .lines()
-            .map(|line| line.parse())
-            .collect::<aoc::Result<_>>()?;
+    fn from_str(s: &str) -> Result<Self> {
+        let instructions = s.lines().map(|line| line.parse()).collect::<Result<_>>()?;
 
         Ok(Program {
             instructions,
diff --git a/aoc2020/src/main.rs b/aoc2020/src/main.rs
index 9255013..104f8af 100644
--- a/aoc2020/src/main.rs
+++ b/aoc2020/src/main.rs
@@ -1,5 +1,6 @@
+use anyhow::Result;
+
 use aoc::DayFunc;
-use aoc::Result;
 
 use aoc2020::day01;
 use aoc2020::day02;