factor out parsing

31 files changed, 661 insertions, 414 deletions

diff --git a/src/2020/1/mod.rs b/src/2020/1/mod.rs
index 8ac5e14..31c4c5d 100644
--- a/src/2020/1/mod.rs
+++ b/src/2020/1/mod.rs
@@ -1,5 +1,8 @@
-pub fn part1() -> anyhow::Result<i64> {
-    let ints: Vec<_> = data_ints!()?.collect();
+pub fn parse(fh: std::fs::File) -> anyhow::Result<Vec<i64>> {
+    Ok(crate::util::parse::ints(crate::util::parse::lines(fh)).collect())
+}
+
+pub fn part1(ints: Vec<i64>) -> anyhow::Result<i64> {
     for i in &ints {
         for j in &ints {
             if i + j == 2020 {
@@ -10,8 +13,7 @@ pub fn part1() -> anyhow::Result<i64> {
     Err(anyhow::anyhow!("no numbers summing to 2020 found"))
 }
 
-pub fn part2() -> anyhow::Result<i64> {
-    let ints: Vec<_> = data_ints!()?.collect();
+pub fn part2(ints: Vec<i64>) -> anyhow::Result<i64> {
     for i in &ints {
         for j in &ints {
             for k in &ints {
@@ -26,6 +28,12 @@ pub fn part2() -> anyhow::Result<i64> {
 
 #[test]
 fn test() {
-    assert_eq!(part1().unwrap(), 445536);
-    assert_eq!(part2().unwrap(), 138688160);
+    assert_eq!(
+        part1(parse(crate::util::data(2020, 1).unwrap()).unwrap()).unwrap(),
+        445536
+    );
+    assert_eq!(
+        part2(parse(crate::util::data(2020, 1).unwrap()).unwrap()).unwrap(),
+        138688160
+    );
 }
diff --git a/src/2020/2/mod.rs b/src/2020/2/mod.rs
index af82ff4..31dfeb5 100644
--- a/src/2020/2/mod.rs
+++ b/src/2020/2/mod.rs
@@ -1,8 +1,7 @@
 use anyhow::Context as _;
 use std::convert::TryInto as _;
-use std::io::BufRead as _;
 
-struct Line {
+pub struct Line {
     c: char,
     n1: usize,
     n2: usize,
@@ -52,28 +51,30 @@ impl Line {
     }
 }
 
-pub fn part1() -> anyhow::Result<i64> {
-    let lines = read_lines()?;
-    let count = lines.iter().filter(|l| l.valid_part_1()).count();
-    Ok(count.try_into()?)
+pub fn parse(
+    fh: std::fs::File,
+) -> anyhow::Result<impl Iterator<Item = Line>> {
+    Ok(crate::util::parse::lines(fh).map(|line| Line::parse(&line).unwrap()))
 }
 
-pub fn part2() -> anyhow::Result<i64> {
-    let lines = read_lines()?;
-    let count = lines.iter().filter(|l| l.valid_part_2()).count();
+pub fn part1(lines: impl Iterator<Item = Line>) -> anyhow::Result<i64> {
+    let count = lines.filter(|l| l.valid_part_1()).count();
     Ok(count.try_into()?)
 }
 
-fn read_lines() -> anyhow::Result<Vec<Line>> {
-    let f = data!()?;
-    let f = std::io::BufReader::new(f);
-    f.lines()
-        .map(|l| Line::parse(&l.context("failed to read a line")?))
-        .collect()
+pub fn part2(lines: impl Iterator<Item = Line>) -> anyhow::Result<i64> {
+    let count = lines.filter(|l| l.valid_part_2()).count();
+    Ok(count.try_into()?)
 }
 
 #[test]
 fn test() {
-    assert_eq!(part1().unwrap(), 638);
-    assert_eq!(part2().unwrap(), 699);
+    assert_eq!(
+        part1(parse(crate::util::data(2020, 2).unwrap()).unwrap()).unwrap(),
+        638
+    );
+    assert_eq!(
+        part2(parse(crate::util::data(2020, 2).unwrap()).unwrap()).unwrap(),
+        699
+    );
 }
diff --git a/src/2020/3/mod.rs b/src/2020/3/mod.rs
index fb4e93d..03ddfce 100644
--- a/src/2020/3/mod.rs
+++ b/src/2020/3/mod.rs
@@ -1,6 +1,6 @@
 use crate::util::grid::*;
 
-struct Map {
+pub struct Map {
     grid: Grid<bool>,
 }
 
@@ -35,13 +35,19 @@ impl Map {
     }
 }
 
-pub fn part1() -> anyhow::Result<i64> {
-    let map = Map::new(data_bool_grid!(b'#', b'.'));
+pub fn parse(fh: std::fs::File) -> anyhow::Result<Map> {
+    Ok(Map::new(crate::util::parse::bool_grid(
+        crate::util::parse::lines(fh),
+        b'#',
+        b'.',
+    )))
+}
+
+pub fn part1(map: Map) -> anyhow::Result<i64> {
     map.trees_for_slope(1, 3)
 }
 
-pub fn part2() -> anyhow::Result<i64> {
-    let map = Map::new(data_bool_grid!(b'#', b'.'));
+pub fn part2(map: Map) -> anyhow::Result<i64> {
     Ok(map.trees_for_slope(1, 1)?
         * map.trees_for_slope(1, 3)?
         * map.trees_for_slope(1, 5)?
@@ -51,6 +57,12 @@ pub fn part2() -> anyhow::Result<i64> {
 
 #[test]
 fn test() {
-    assert_eq!(part1().unwrap(), 292);
-    assert_eq!(part2().unwrap(), 9354744432);
+    assert_eq!(
+        part1(parse(crate::util::data(2020, 3).unwrap()).unwrap()).unwrap(),
+        292
+    );
+    assert_eq!(
+        part2(parse(crate::util::data(2020, 3).unwrap()).unwrap()).unwrap(),
+        9354744432
+    );
 }
diff --git a/src/2020/4/mod.rs b/src/2020/4/mod.rs
index 5eace5a..f89993e 100644
--- a/src/2020/4/mod.rs
+++ b/src/2020/4/mod.rs
@@ -3,10 +3,40 @@ use anyhow::Context as _;
 const REQUIRED_KEYS: &[&str] =
     &["byr", "iyr", "eyr", "hgt", "hcl", "ecl", "pid"];
 
-pub fn part1() -> anyhow::Result<i64> {
-    let batch = data_str!()?;
+pub fn parse(
+    fh: std::fs::File,
+) -> anyhow::Result<Vec<std::collections::HashMap<String, String>>> {
+    let mut res = vec![];
+    let mut cur = std::collections::HashMap::new();
+    for line in crate::util::parse::lines(fh) {
+        if line.is_empty() {
+            res.push(cur);
+            cur = std::collections::HashMap::new();
+            continue;
+        }
+
+        for field in line.split(' ') {
+            let mut parts = field.split(':');
+            let key = parts.next().with_context(|| {
+                format!("failed to parse field '{}'", field)
+            })?;
+            let value = parts.next().with_context(|| {
+                format!("failed to parse field '{}'", field)
+            })?;
+            cur.insert(key.to_string(), value.to_string());
+        }
+    }
+    if !cur.is_empty() {
+        res.push(cur);
+    }
+    Ok(res)
+}
+
+pub fn part1(
+    passports: Vec<std::collections::HashMap<String, String>>,
+) -> anyhow::Result<i64> {
     let mut valid = 0;
-    for passport in parse(&batch)? {
+    for passport in passports {
         let mut cur_valid = true;
         for key in REQUIRED_KEYS {
             if !passport.contains_key(&key.to_string()) {
@@ -21,10 +51,11 @@ pub fn part1() -> anyhow::Result<i64> {
     Ok(valid)
 }
 
-pub fn part2() -> anyhow::Result<i64> {
-    let batch = data_str!()?;
+pub fn part2(
+    passports: Vec<std::collections::HashMap<String, String>>,
+) -> anyhow::Result<i64> {
     let mut valid = 0;
-    for passport in parse(&batch)? {
+    for passport in passports {
         let mut cur_valid = true;
         for key in REQUIRED_KEYS {
             match passport.get(&key.to_string()) {
@@ -47,35 +78,6 @@ pub fn part2() -> anyhow::Result<i64> {
     Ok(valid)
 }
 
-fn parse(
-    batch: &str,
-) -> anyhow::Result<Vec<std::collections::HashMap<String, String>>> {
-    let mut res = vec![];
-    let mut cur = std::collections::HashMap::new();
-    for line in batch.lines() {
-        if line.is_empty() {
-            res.push(cur);
-            cur = std::collections::HashMap::new();
-            continue;
-        }
-
-        for field in line.split(' ') {
-            let mut parts = field.split(':');
-            let key = parts.next().with_context(|| {
-                format!("failed to parse field '{}'", field)
-            })?;
-            let value = parts.next().with_context(|| {
-                format!("failed to parse field '{}'", field)
-            })?;
-            cur.insert(key.to_string(), value.to_string());
-        }
-    }
-    if !cur.is_empty() {
-        res.push(cur);
-    }
-    Ok(res)
-}
-
 fn validate(key: &str, val: &str) -> anyhow::Result<bool> {
     match key {
         "byr" => match val.parse::<i32>() {
@@ -131,6 +133,12 @@ fn validate(key: &str, val: &str) -> anyhow::Result<bool> {
 
 #[test]
 fn test() {
-    assert_eq!(part1().unwrap(), 247);
-    assert_eq!(part2().unwrap(), 145);
+    assert_eq!(
+        part1(parse(crate::util::data(2020, 4).unwrap()).unwrap()).unwrap(),
+        247
+    );
+    assert_eq!(
+        part2(parse(crate::util::data(2020, 4).unwrap()).unwrap()).unwrap(),
+        145
+    );
 }
diff --git a/src/2020/5/mod.rs b/src/2020/5/mod.rs
index e7c0f6e..b824e60 100644
--- a/src/2020/5/mod.rs
+++ b/src/2020/5/mod.rs
@@ -1,11 +1,13 @@
 use anyhow::Context as _;
 use std::convert::TryInto as _;
 
-pub fn part1() -> anyhow::Result<i64> {
-    let input = data_str!()?;
+pub fn parse(fh: std::fs::File) -> anyhow::Result<impl Iterator<Item = i64>> {
+    Ok(crate::util::parse::lines(fh).map(|line| seat_id(&line).unwrap()))
+}
+
+pub fn part1(ids: impl Iterator<Item = i64>) -> anyhow::Result<i64> {
     let mut max = 0;
-    for line in input.lines() {
-        let id = seat_id(line)?;
+    for id in ids {
         if id > max {
             max = id;
         }
@@ -13,11 +15,9 @@ pub fn part1() -> anyhow::Result<i64> {
     Ok(max)
 }
 
-pub fn part2() -> anyhow::Result<i64> {
+pub fn part2(ids: impl Iterator<Item = i64>) -> anyhow::Result<i64> {
     let mut seats = vec![false; 1024];
-    let input = data_str!()?;
-    for line in input.lines() {
-        let id = seat_id(line)?;
+    for id in ids {
         seats[id as usize] = true;
     }
     let first = seats
@@ -86,6 +86,12 @@ fn seat_id(desc: &str) -> anyhow::Result<i64> {
 
 #[test]
 fn test() {
-    assert_eq!(part1().unwrap(), 978);
-    assert_eq!(part2().unwrap(), 727);
+    assert_eq!(
+        part1(parse(crate::util::data(2020, 5).unwrap()).unwrap()).unwrap(),
+        978
+    );
+    assert_eq!(
+        part2(parse(crate::util::data(2020, 5).unwrap()).unwrap()).unwrap(),
+        727
+    );
 }
diff --git a/src/2020/6/mod.rs b/src/2020/6/mod.rs
index 5e918d7..21279af 100644
--- a/src/2020/6/mod.rs
+++ b/src/2020/6/mod.rs
@@ -1,8 +1,13 @@
-pub fn part1() -> anyhow::Result<i64> {
-    let input = data_str!()?;
+pub fn parse(
+    fh: std::fs::File,
+) -> anyhow::Result<impl Iterator<Item = String>> {
+    Ok(crate::util::parse::lines(fh))
+}
+
+pub fn part1(lines: impl Iterator<Item = String>) -> anyhow::Result<i64> {
     let mut yes = std::collections::HashSet::new();
     let mut total = 0;
-    for line in input.lines() {
+    for line in lines {
         if line.is_empty() {
             total += yes.len() as i64;
             yes = std::collections::HashSet::new();
@@ -16,14 +21,13 @@ pub fn part1() -> anyhow::Result<i64> {
     Ok(total)
 }
 
-pub fn part2() -> anyhow::Result<i64> {
-    let input = data_str!()?;
+pub fn part2(lines: impl Iterator<Item = String>) -> anyhow::Result<i64> {
     let mut yes = std::collections::HashSet::new();
     for c in 'a'..='z' {
         yes.insert(c);
     }
     let mut total = 0;
-    for line in input.lines() {
+    for line in lines {
         if line.is_empty() {
             total += yes.len() as i64;
             yes = std::collections::HashSet::new();
@@ -44,6 +48,12 @@ pub fn part2() -> anyhow::Result<i64> {
 
 #[test]
 fn test() {
-    assert_eq!(part1().unwrap(), 6930);
-    assert_eq!(part2().unwrap(), 3585);
+    assert_eq!(
+        part1(parse(crate::util::data(2020, 6).unwrap()).unwrap()).unwrap(),
+        6930
+    );
+    assert_eq!(
+        part2(parse(crate::util::data(2020, 6).unwrap()).unwrap()).unwrap(),
+        3585
+    );
 }
diff --git a/src/2020/7/mod.rs b/src/2020/7/mod.rs
index b293f28..fbf2c43 100644
--- a/src/2020/7/mod.rs
+++ b/src/2020/7/mod.rs
@@ -2,9 +2,17 @@ use anyhow::Context as _;
 
 type Graph = std::collections::HashMap<String, Vec<(i64, String)>>;
 
-pub fn part1() -> anyhow::Result<i64> {
-    let input = data_str!()?;
-    let graph = parse(&input)?;
+pub fn parse(fh: std::fs::File) -> anyhow::Result<Graph> {
+    let input = crate::util::parse::string(fh);
+    let mut graph = Graph::new();
+    for line in input.lines() {
+        let (k, v) = parse_line(line)?;
+        graph.insert(k, v);
+    }
+    Ok(graph)
+}
+
+pub fn part1(graph: Graph) -> anyhow::Result<i64> {
     let mut colors = 0;
     for color in graph.keys() {
         if bag_contains(&graph, color, "shiny gold")? {
@@ -14,22 +22,11 @@ pub fn part1() -> anyhow::Result<i64> {
     Ok(colors)
 }
 
-pub fn part2() -> anyhow::Result<i64> {
-    let input = data_str!()?;
-    let graph = parse(&input)?;
+pub fn part2(graph: Graph) -> anyhow::Result<i64> {
     // subtract 1 to not count the shiny gold bag itself
     count_bags(&graph, "shiny gold").map(|i| i - 1)
 }
 
-fn parse(input: &str) -> anyhow::Result<Graph> {
-    let mut graph = Graph::new();
-    for line in input.lines() {
-        let (k, v) = parse_line(line)?;
-        graph.insert(k, v);
-    }
-    Ok(graph)
-}
-
 fn parse_line(line: &str) -> anyhow::Result<(String, Vec<(i64, String)>)> {
     let main_rx = regex::Regex::new(r"^(.*) bags contain (.*)\.$").unwrap();
     let contents_rx = regex::Regex::new(r"^([0-9]+) (.*) bags?").unwrap();
@@ -102,6 +99,12 @@ fn count_bags(graph: &Graph, color: &str) -> anyhow::Result<i64> {
 
 #[test]
 fn test() {
-    assert_eq!(part1().unwrap(), 169);
-    assert_eq!(part2().unwrap(), 82372);
+    assert_eq!(
+        part1(parse(crate::util::data(2020, 7).unwrap()).unwrap()).unwrap(),
+        169
+    );
+    assert_eq!(
+        part2(parse(crate::util::data(2020, 7).unwrap()).unwrap()).unwrap(),
+        82372
+    );
 }
diff --git a/src/2020/8/mod.rs b/src/2020/8/mod.rs
index 0756fe5..052538e 100644
--- a/src/2020/8/mod.rs
+++ b/src/2020/8/mod.rs
@@ -21,7 +21,7 @@ impl std::str::FromStr for OpType {
 }
 
 #[derive(Clone, Copy)]
-struct Op {
+pub struct Op {
     ty: OpType,
     arg: i64,
 }
@@ -43,9 +43,13 @@ impl std::str::FromStr for Op {
     }
 }
 
-pub fn part1() -> anyhow::Result<i64> {
-    let input = data_str!()?;
-    let opcodes = parse(&input)?;
+pub fn parse(fh: std::fs::File) -> anyhow::Result<Vec<Op>> {
+    crate::util::parse::lines(fh)
+        .map(|line| line.parse())
+        .collect()
+}
+
+pub fn part1(opcodes: Vec<Op>) -> anyhow::Result<i64> {
     let (acc, success) = run(&opcodes)?;
     if success {
         return Err(anyhow::anyhow!("unexpectedly succeeded"));
@@ -53,9 +57,7 @@ pub fn part1() -> anyhow::Result<i64> {
     Ok(acc)
 }
 
-pub fn part2() -> anyhow::Result<i64> {
-    let input = data_str!()?;
-    let opcodes = parse(&input)?;
+pub fn part2(opcodes: Vec<Op>) -> anyhow::Result<i64> {
     for i in 0..opcodes.len() {
         match opcodes[i].ty {
             OpType::Nop => {
@@ -80,10 +82,6 @@ pub fn part2() -> anyhow::Result<i64> {
     Err(anyhow::anyhow!("failed to find corrupted opcode"))
 }
 
-fn parse(input: &str) -> anyhow::Result<Vec<Op>> {
-    input.lines().map(|line| line.parse()).collect()
-}
-
 fn run(opcodes: &[Op]) -> anyhow::Result<(i64, bool)> {
     let mut seen = vec![false; opcodes.len()];
     let mut pc = 0;
@@ -126,6 +124,12 @@ fn run(opcodes: &[Op]) -> anyhow::Result<(i64, bool)> {
 
 #[test]
 fn test() {
-    assert_eq!(part1().unwrap(), 1928);
-    assert_eq!(part2().unwrap(), 1319);
+    assert_eq!(
+        part1(parse(crate::util::data(2020, 8).unwrap()).unwrap()).unwrap(),
+        1928
+    );
+    assert_eq!(
+        part2(parse(crate::util::data(2020, 8).unwrap()).unwrap()).unwrap(),
+        1319
+    );
 }
diff --git a/src/2020/9/mod.rs b/src/2020/9/mod.rs
index 9d1bc9f..c067ca0 100644
--- a/src/2020/9/mod.rs
+++ b/src/2020/9/mod.rs
@@ -1,7 +1,10 @@
-pub fn part1() -> anyhow::Result<i64> {
-    const WINDOW: usize = 25;
+const WINDOW: usize = 25;
 
-    let list: Vec<_> = data_ints!()?.collect();
+pub fn parse(fh: std::fs::File) -> anyhow::Result<Vec<i64>> {
+    Ok(crate::util::parse::ints(crate::util::parse::lines(fh)).collect())
+}
+
+pub fn part1(list: Vec<i64>) -> anyhow::Result<i64> {
     for i in 0..(list.len() - WINDOW) {
         let set = &list[i..i + WINDOW];
         let n = list[i + WINDOW];
@@ -13,10 +16,7 @@ pub fn part1() -> anyhow::Result<i64> {
     Err(anyhow::anyhow!("failed to find invalid number"))
 }
 
-pub fn part2() -> anyhow::Result<i64> {
-    const WINDOW: usize = 25;
-
-    let list: Vec<_> = data_ints!()?.collect();
+pub fn part2(list: Vec<i64>) -> anyhow::Result<i64> {
     let mut invalid = None;
     for i in 0..(list.len() - WINDOW) {
         let set = &list[i..i + WINDOW];
@@ -63,6 +63,12 @@ fn valid(set: &[i64], n: i64) -> bool {
 
 #[test]
 fn test() {
-    assert_eq!(part1().unwrap(), 373803594);
-    assert_eq!(part2().unwrap(), 51152360);
+    assert_eq!(
+        part1(parse(crate::util::data(2020, 9).unwrap()).unwrap()).unwrap(),
+        373803594
+    );
+    assert_eq!(
+        part2(parse(crate::util::data(2020, 9).unwrap()).unwrap()).unwrap(),
+        51152360
+    );
 }
diff --git a/src/2020/mod.rs b/src/2020/mod.rs
index 7a41d7c..b4ea179 100644
--- a/src/2020/mod.rs
+++ b/src/2020/mod.rs
@@ -20,24 +20,24 @@ mod day9;
 
 pub fn run(day: u8, puzzle: u8) -> anyhow::Result<i64> {
     match (day, puzzle) {
-        (1, 1) => day1::part1(),
-        (1, 2) => day1::part2(),
-        (2, 1) => day2::part1(),
-        (2, 2) => day2::part2(),
-        (3, 1) => day3::part1(),
-        (3, 2) => day3::part2(),
-        (4, 1) => day4::part1(),
-        (4, 2) => day4::part2(),
-        (5, 1) => day5::part1(),
-        (5, 2) => day5::part2(),
-        (6, 1) => day6::part1(),
-        (6, 2) => day6::part2(),
-        (7, 1) => day7::part1(),
-        (7, 2) => day7::part2(),
-        (8, 1) => day8::part1(),
-        (8, 2) => day8::part2(),
-        (9, 1) => day9::part1(),
-        (9, 2) => day9::part2(),
+        (1, 1) => day1::part1(day1::parse(crate::util::data(2020, 1)?)?),
+        (1, 2) => day1::part2(day1::parse(crate::util::data(2020, 1)?)?),
+        (2, 1) => day2::part1(day2::parse(crate::util::data(2020, 2)?)?),
+        (2, 2) => day2::part2(day2::parse(crate::util::data(2020, 2)?)?),
+        (3, 1) => day3::part1(day3::parse(crate::util::data(2020, 3)?)?),
+        (3, 2) => day3::part2(day3::parse(crate::util::data(2020, 3)?)?),
+        (4, 1) => day4::part1(day4::parse(crate::util::data(2020, 4)?)?),
+        (4, 2) => day4::part2(day4::parse(crate::util::data(2020, 4)?)?),
+        (5, 1) => day5::part1(day5::parse(crate::util::data(2020, 5)?)?),
+        (5, 2) => day5::part2(day5::parse(crate::util::data(2020, 5)?)?),
+        (6, 1) => day6::part1(day6::parse(crate::util::data(2020, 6)?)?),
+        (6, 2) => day6::part2(day6::parse(crate::util::data(2020, 6)?)?),
+        (7, 1) => day7::part1(day7::parse(crate::util::data(2020, 7)?)?),
+        (7, 2) => day7::part2(day7::parse(crate::util::data(2020, 7)?)?),
+        (8, 1) => day8::part1(day8::parse(crate::util::data(2020, 8)?)?),
+        (8, 2) => day8::part2(day8::parse(crate::util::data(2020, 8)?)?),
+        (9, 1) => day9::part1(day9::parse(crate::util::data(2020, 9)?)?),
+        (9, 2) => day9::part2(day9::parse(crate::util::data(2020, 9)?)?),
         // NEXT PART
         _ => Err(anyhow::anyhow!("unknown puzzle {}-{}", day, puzzle)),
     }
diff --git a/src/2021/1/mod.rs b/src/2021/1/mod.rs
index be03275..3ba61e2 100644
--- a/src/2021/1/mod.rs
+++ b/src/2021/1/mod.rs
@@ -1,6 +1,9 @@
-pub fn part1() -> anyhow::Result<i64> {
-    Ok(data_ints!()?
-        .collect::<Vec<_>>()
+pub fn parse(fh: std::fs::File) -> anyhow::Result<Vec<i64>> {
+    Ok(crate::util::parse::ints(crate::util::parse::lines(fh)).collect())
+}
+
+pub fn part1(ints: Vec<i64>) -> anyhow::Result<i64> {
+    Ok(ints
         .windows(2)
         .map(|a| a[1] - a[0])
         .filter(|x| *x > 0)
@@ -8,9 +11,8 @@ pub fn part1() -> anyhow::Result<i64> {
         .try_into()?)
 }
 
-pub fn part2() -> anyhow::Result<i64> {
-    Ok(data_ints!()?
-        .collect::<Vec<_>>()
+pub fn part2(ints: Vec<i64>) -> anyhow::Result<i64> {
+    Ok(ints
         .windows(3)
         .map(|a| a[0] + a[1] + a[2])
         .collect::<Vec<_>>()
@@ -23,6 +25,12 @@ pub fn part2() -> anyhow::Result<i64> {
 
 #[test]
 fn test() {
-    assert_eq!(part1().unwrap(), 1602);
-    assert_eq!(part2().unwrap(), 1633);
+    assert_eq!(
+        part1(parse(crate::util::data(2021, 1).unwrap()).unwrap()).unwrap(),
+        1602
+    );
+    assert_eq!(
+        part2(parse(crate::util::data(2021, 1).unwrap()).unwrap()).unwrap(),
+        1633
+    );
 }
diff --git a/src/2021/10/mod.rs b/src/2021/10/mod.rs
index 29cced2..ae311e8 100644
--- a/src/2021/10/mod.rs
+++ b/src/2021/10/mod.rs
@@ -1,6 +1,12 @@
-pub fn part1() -> anyhow::Result<i64> {
+pub fn parse(
+    fh: std::fs::File,
+) -> anyhow::Result<impl Iterator<Item = String>> {
+    Ok(crate::util::parse::lines(fh))
+}
+
+pub fn part1(lines: impl Iterator<Item = String>) -> anyhow::Result<i64> {
     let mut total = 0;
-    for line in data_lines!()? {
+    for line in lines {
         let mut open = vec![];
         for c in line.chars() {
             match c {
@@ -38,9 +44,9 @@ pub fn part1() -> anyhow::Result<i64> {
     Ok(total)
 }
 
-pub fn part2() -> anyhow::Result<i64> {
+pub fn part2(lines: impl Iterator<Item = String>) -> anyhow::Result<i64> {
     let mut scores = vec![];
-    for line in data_lines!()? {
+    for line in lines {
         let mut open = vec![];
         let mut skip = false;
         for c in line.chars() {
@@ -92,6 +98,12 @@ pub fn part2() -> anyhow::Result<i64> {
 
 #[test]
 fn test() {
-    assert_eq!(part1().unwrap(), 166191);
-    assert_eq!(part2().unwrap(), 1152088313);
+    assert_eq!(
+        part1(parse(crate::util::data(2021, 10).unwrap()).unwrap()).unwrap(),
+        166191
+    );
+    assert_eq!(
+        part2(parse(crate::util::data(2021, 10).unwrap()).unwrap()).unwrap(),
+        1152088313
+    );
 }
diff --git a/src/2021/11/mod.rs b/src/2021/11/mod.rs
index f7f3b99..38a1836 100644
--- a/src/2021/11/mod.rs
+++ b/src/2021/11/mod.rs
@@ -42,11 +42,16 @@ fn iterate(grid: &mut Grid<(u8, bool)>) -> i64 {
     flashes
 }
 
-pub fn part1() -> anyhow::Result<i64> {
-    let mut map = data_digit_grid!()
-        .indexed_cells()
-        .map(|((row, col), cell)| ((row, col), (*cell, false)))
-        .collect();
+pub fn parse(fh: std::fs::File) -> anyhow::Result<Grid<(u8, bool)>> {
+    Ok(
+        crate::util::parse::digit_grid(crate::util::parse::lines(fh))
+            .indexed_cells()
+            .map(|((row, col), cell)| ((row, col), (*cell, false)))
+            .collect(),
+    )
+}
+
+pub fn part1(mut map: Grid<(u8, bool)>) -> anyhow::Result<i64> {
     let mut flashes = 0;
     for _ in 0..100 {
         flashes += iterate(&mut map);
@@ -54,12 +59,7 @@ pub fn part1() -> anyhow::Result<i64> {
     Ok(flashes)
 }
 
-pub fn part2() -> anyhow::Result<i64> {
-    let mut map = data_digit_grid!()
-        .indexed_cells()
-        .map(|((row, col), cell)| ((row, col), (*cell, false)))
-        .collect();
-
+pub fn part2(mut map: Grid<(u8, bool)>) -> anyhow::Result<i64> {
     let mut step = 1;
     loop {
         let flashes = iterate(&mut map);
@@ -73,6 +73,12 @@ pub fn part2() -> anyhow::Result<i64> {
 
 #[test]
 fn test() {
-    assert_eq!(part1().unwrap(), 1673);
-    assert_eq!(part2().unwrap(), 279);
+    assert_eq!(
+        part1(parse(crate::util::data(2021, 11).unwrap()).unwrap()).unwrap(),
+        1673
+    );
+    assert_eq!(
+        part2(parse(crate::util::data(2021, 11).unwrap()).unwrap()).unwrap(),
+        279
+    );
 }
diff --git a/src/2021/12/mod.rs b/src/2021/12/mod.rs
index 022a8b8..5907e67 100644
--- a/src/2021/12/mod.rs
+++ b/src/2021/12/mod.rs
@@ -68,9 +68,13 @@ fn paths_from2<'a>(
     total
 }
 
-pub fn part1() -> anyhow::Result<i64> {
+pub fn parse(
+    fh: std::fs::File,
+) -> anyhow::Result<
+    std::collections::HashMap<String, std::collections::HashSet<String>>,
+> {
     let mut graph = std::collections::HashMap::new();
-    for line in data_lines!()? {
+    for line in crate::util::parse::lines(fh) {
         let nodes: Vec<String> =
             line.split('-').map(|s| s.to_string()).collect();
         let edges = graph
@@ -82,28 +86,35 @@ pub fn part1() -> anyhow::Result<i64> {
             .or_insert_with(std::collections::HashSet::new);
         edges.insert(nodes[0].clone());
     }
+    Ok(graph)
+}
+
+pub fn part1(
+    graph: std::collections::HashMap<
+        String,
+        std::collections::HashSet<String>,
+    >,
+) -> anyhow::Result<i64> {
     Ok(paths_from1(&graph, &mut vec!["start"]))
 }
 
-pub fn part2() -> anyhow::Result<i64> {
-    let mut graph = std::collections::HashMap::new();
-    for line in data_lines!()? {
-        let nodes: Vec<String> =
-            line.split('-').map(|s| s.to_string()).collect();
-        let edges = graph
-            .entry(nodes[0].clone())
-            .or_insert_with(std::collections::HashSet::new);
-        edges.insert(nodes[1].clone());
-        let edges = graph
-            .entry(nodes[1].clone())
-            .or_insert_with(std::collections::HashSet::new);
-        edges.insert(nodes[0].clone());
-    }
+pub fn part2(
+    graph: std::collections::HashMap<
+        String,
+        std::collections::HashSet<String>,
+    >,
+) -> anyhow::Result<i64> {
     Ok(paths_from2(&graph, &mut vec!["start"]))
 }
 
 #[test]
 fn test() {
-    assert_eq!(part1().unwrap(), 3230);
-    assert_eq!(part2().unwrap(), 83475);
+    assert_eq!(
+        part1(parse(crate::util::data(2021, 12).unwrap()).unwrap()).unwrap(),
+        3230
+    );
+    assert_eq!(
+        part2(parse(crate::util::data(2021, 12).unwrap()).unwrap()).unwrap(),
+        83475
+    );
 }
diff --git a/src/2021/13/mod.rs b/src/2021/13/mod.rs
index 0be74d1..717e032 100644
--- a/src/2021/13/mod.rs
+++ b/src/2021/13/mod.rs
@@ -4,7 +4,7 @@
 use crate::util::grid::*;
 
 #[derive(Default)]
-struct Paper {
+pub struct Paper {
     grid: Grid<bool>,
 }
 
@@ -94,10 +94,12 @@ impl std::fmt::Display for Paper {
     }
 }
 
-pub fn part1() -> anyhow::Result<i64> {
+pub fn parse(
+    fh: std::fs::File,
+) -> anyhow::Result<(Paper, Vec<(bool, usize)>)> {
     let mut paper = Paper::default();
     let mut folds = vec![];
-    for line in data_lines!()? {
+    for line in crate::util::parse::lines(fh) {
         if line.is_empty() {
             continue;
         }
@@ -113,31 +115,19 @@ pub fn part1() -> anyhow::Result<i64> {
             paper.set(Row(y), Col(x));
         }
     }
+    Ok((paper, folds))
+}
 
+pub fn part1(
+    (mut paper, folds): (Paper, Vec<(bool, usize)>),
+) -> anyhow::Result<i64> {
     paper.fold(folds[0].0, folds[0].1);
     Ok(paper.total())
 }
 
-pub fn part2() -> anyhow::Result<i64> {
-    let mut paper = Paper::default();
-    let mut folds = vec![];
-    for line in data_lines!()? {
-        if line.is_empty() {
-            continue;
-        }
-        if let Some(fold) = line.strip_prefix("fold along ") {
-            let mut fold = fold.split('=');
-            let horizontal = fold.next().unwrap() == "x";
-            let coord: usize = fold.next().unwrap().parse()?;
-            folds.push((horizontal, coord));
-        } else {
-            let mut coords = line.split(',');
-            let x: usize = coords.next().unwrap().parse()?;
-            let y: usize = coords.next().unwrap().parse()?;
-            paper.set(Row(y), Col(x));
-        }
-    }
-
+pub fn part2(
+    (mut paper, folds): (Paper, Vec<(bool, usize)>),
+) -> anyhow::Result<i64> {
     for fold in folds {
         paper.fold(fold.0, fold.1);
     }
@@ -148,6 +138,12 @@ pub fn part2() -> anyhow::Result<i64> {
 
 #[test]
 fn test() {
-    assert_eq!(part1().unwrap(), 678);
-    assert_eq!(part2().unwrap(), 95);
+    assert_eq!(
+        part1(parse(crate::util::data(2021, 13).unwrap()).unwrap()).unwrap(),
+        678
+    );
+    assert_eq!(
+        part2(parse(crate::util::data(2021, 13).unwrap()).unwrap()).unwrap(),
+        95
+    );
 }
diff --git a/src/2021/14/mod.rs b/src/2021/14/mod.rs
index fb36468..97c2e9c 100644
--- a/src/2021/14/mod.rs
+++ b/src/2021/14/mod.rs
@@ -1,18 +1,3 @@
-#[allow(clippy::type_complexity)]
-fn parse() -> anyhow::Result<(Vec<u8>, std::collections::HashMap<Vec<u8>, u8>)>
-{
-    let mut lines = data_lines!()?;
-    let polymer = lines.next().unwrap();
-    lines.next();
-
-    let mut rules = std::collections::HashMap::new();
-    for line in lines {
-        let rule: Vec<_> = line.split(" -> ").collect();
-        rules.insert(rule[0].as_bytes().to_vec(), rule[1].as_bytes()[0]);
-    }
-    Ok((polymer.as_bytes().to_vec(), rules))
-}
-
 fn process(
     polymer: &[u8],
     rules: &std::collections::HashMap<Vec<u8>, u8>,
@@ -32,9 +17,25 @@ fn process(
     polymer
 }
 
-pub fn part1() -> anyhow::Result<i64> {
-    let (mut polymer, rules) = parse()?;
+#[allow(clippy::type_complexity)]
+pub fn parse(
+    fh: std::fs::File,
+) -> anyhow::Result<(Vec<u8>, std::collections::HashMap<Vec<u8>, u8>)> {
+    let mut lines = crate::util::parse::lines(fh);
+    let polymer = lines.next().unwrap();
+    lines.next();
+
+    let mut rules = std::collections::HashMap::new();
+    for line in lines {
+        let rule: Vec<_> = line.split(" -> ").collect();
+        rules.insert(rule[0].as_bytes().to_vec(), rule[1].as_bytes()[0]);
+    }
+    Ok((polymer.as_bytes().to_vec(), rules))
+}
 
+pub fn part1(
+    (mut polymer, rules): (Vec<u8>, std::collections::HashMap<Vec<u8>, u8>),
+) -> anyhow::Result<i64> {
     for _ in 0..10 {
         polymer = process(&polymer, &rules);
     }
@@ -46,9 +47,9 @@ pub fn part1() -> anyhow::Result<i64> {
     Ok(elements.values().max().unwrap() - elements.values().min().unwrap())
 }
 
-pub fn part2() -> anyhow::Result<i64> {
-    let (polymer, rules) = parse()?;
-
+pub fn part2(
+    (polymer, rules): (Vec<u8>, std::collections::HashMap<Vec<u8>, u8>),
+) -> anyhow::Result<i64> {
     let mut pairs = std::collections::HashMap::new();
     for pair in polymer.windows(2) {
         let count = pairs.entry([pair[0], pair[1]]).or_insert(0);
@@ -86,6 +87,12 @@ pub fn part2() -> anyhow::Result<i64> {
 
 #[test]
 fn test() {
-    assert_eq!(part1().unwrap(), 2874);
-    assert_eq!(part2().unwrap(), 5208377027195);
+    assert_eq!(
+        part1(parse(crate::util::data(2021, 14).unwrap()).unwrap()).unwrap(),
+        2874
+    );
+    assert_eq!(
+        part2(parse(crate::util::data(2021, 14).unwrap()).unwrap()).unwrap(),
+        5208377027195
+    );
 }
diff --git a/src/2021/15/mod.rs b/src/2021/15/mod.rs
index fa1d82a..e2d0656 100644
--- a/src/2021/15/mod.rs
+++ b/src/2021/15/mod.rs
@@ -40,12 +40,17 @@ fn dijkstra(map: &Grid<u8>) -> i64 {
     unreachable!()
 }
 
-pub fn part1() -> anyhow::Result<i64> {
-    Ok(dijkstra(&data_digit_grid!()))
+pub fn parse(fh: std::fs::File) -> anyhow::Result<Grid<u8>> {
+    Ok(crate::util::parse::digit_grid(crate::util::parse::lines(
+        fh,
+    )))
 }
 
-pub fn part2() -> anyhow::Result<i64> {
-    let grid = data_digit_grid!();
+pub fn part1(grid: Grid<u8>) -> anyhow::Result<i64> {
+    Ok(dijkstra(&grid))
+}
+
+pub fn part2(grid: Grid<u8>) -> anyhow::Result<i64> {
     let mut large_grid = Grid::default();
     large_grid.grow(Row(grid.rows().0 * 5), Col(grid.cols().0 * 5));
     for lrow in 0..5 {
@@ -65,6 +70,12 @@ pub fn part2() -> anyhow::Result<i64> {
 
 #[test]
 fn test() {
-    assert_eq!(part1().unwrap(), 441);
-    assert_eq!(part2().unwrap(), 2849);
+    assert_eq!(
+        part1(parse(crate::util::data(2021, 15).unwrap()).unwrap()).unwrap(),
+        441
+    );
+    assert_eq!(
+        part2(parse(crate::util::data(2021, 15).unwrap()).unwrap()).unwrap(),
+        2849
+    );
 }
diff --git a/src/2021/16/mod.rs b/src/2021/16/mod.rs
index fd57965..4a66fa8 100644
--- a/src/2021/16/mod.rs
+++ b/src/2021/16/mod.rs
@@ -58,7 +58,7 @@ impl FromIterator<bool> for LiteralU16 {
     }
 }
 
-struct Packet {
+pub struct Packet {
     version: u8,
     id: u8,
     contents: PacketContents,
@@ -193,29 +193,34 @@ impl<'a> Iterator for Subpackets<'a> {
     }
 }
 
-pub fn part1() -> anyhow::Result<i64> {
-    let line = data_lines!()?.next().unwrap();
+pub fn parse(fh: std::fs::File) -> anyhow::Result<Packet> {
+    let line = crate::util::parse::lines(fh).next().unwrap();
     let mut bits = bits(line.as_bytes().chunks(2).map(|bs| {
         u8::from_str_radix(std::str::from_utf8(bs).unwrap(), 16).unwrap()
     }));
     let (packet, _) = Packet::parse(bits.by_ref());
+    Ok(packet)
+}
+
+pub fn part1(packet: Packet) -> anyhow::Result<i64> {
     Ok(packet
         .subpackets()
         .map(|packet| i64::from(packet.version))
         .sum())
 }
 
-pub fn part2() -> anyhow::Result<i64> {
-    let line = data_lines!()?.next().unwrap();
-    let mut bits = bits(line.as_bytes().chunks(2).map(|bs| {
-        u8::from_str_radix(std::str::from_utf8(bs).unwrap(), 16).unwrap()
-    }));
-    let (packet, _) = Packet::parse(bits.by_ref());
+pub fn part2(packet: Packet) -> anyhow::Result<i64> {
     Ok(packet.eval())
 }
 
 #[test]
 fn test() {
-    assert_eq!(part1().unwrap(), 979);
-    assert_eq!(part2().unwrap(), 277110354175);
+    assert_eq!(
+        part1(parse(crate::util::data(2021, 16).unwrap()).unwrap()).unwrap(),
+        979
+    );
+    assert_eq!(
+        part2(parse(crate::util::data(2021, 16).unwrap()).unwrap()).unwrap(),
+        277110354175
+    );
 }
diff --git a/src/2021/17/mod.rs b/src/2021/17/mod.rs
index 5bf6651..806d9c1 100644
--- a/src/2021/17/mod.rs
+++ b/src/2021/17/mod.rs
@@ -35,18 +35,31 @@ fn fire(
     }
 }
 
-pub fn part1() -> anyhow::Result<i64> {
+pub fn parse(
+    fh: std::fs::File,
+) -> anyhow::Result<(
+    std::ops::RangeInclusive<i64>,
+    std::ops::RangeInclusive<i64>,
+)> {
     let rx = regex::Regex::new(
         r"target area: x=(-?\d+)..(-?\d+), y=(-?\d+)..(-?\d+)",
     )
     .unwrap();
-    let line = data_lines!()?.next().unwrap();
+    let line = crate::util::parse::lines(fh).next().unwrap();
     let captures = rx.captures(&line).unwrap();
     let xrange: std::ops::RangeInclusive<i64> =
         captures[1].parse().unwrap()..=captures[2].parse().unwrap();
     let yrange: std::ops::RangeInclusive<i64> =
         captures[3].parse().unwrap()..=captures[4].parse().unwrap();
+    Ok((xrange, yrange))
+}
 
+pub fn part1(
+    (xrange, yrange): (
+        std::ops::RangeInclusive<i64>,
+        std::ops::RangeInclusive<i64>,
+    ),
+) -> anyhow::Result<i64> {
     let mut max_height = 0;
     for xv in *xrange.start().min(&0)..=*xrange.end().max(&0) {
         for yv in *yrange.start().min(&0)
@@ -62,18 +75,12 @@ pub fn part1() -> anyhow::Result<i64> {
     Ok(max_height)
 }
 
-pub fn part2() -> anyhow::Result<i64> {
-    let rx = regex::Regex::new(
-        r"target area: x=(-?\d+)..(-?\d+), y=(-?\d+)..(-?\d+)",
-    )
-    .unwrap();
-    let line = data_lines!()?.next().unwrap();
-    let captures = rx.captures(&line).unwrap();
-    let xrange: std::ops::RangeInclusive<i64> =
-        captures[1].parse().unwrap()..=captures[2].parse().unwrap();
-    let yrange: std::ops::RangeInclusive<i64> =
-        captures[3].parse().unwrap()..=captures[4].parse().unwrap();
-
+pub fn part2(
+    (xrange, yrange): (
+        std::ops::RangeInclusive<i64>,
+        std::ops::RangeInclusive<i64>,
+    ),
+) -> anyhow::Result<i64> {
     let mut count = 0;
     for xv in *xrange.start().min(&0)..=*xrange.end().max(&0) {
         for yv in *yrange.start().min(&0)
@@ -89,6 +96,12 @@ pub fn part2() -> anyhow::Result<i64> {
 
 #[test]
 fn test() {
-    assert_eq!(part1().unwrap(), 5886);
-    assert_eq!(part2().unwrap(), 1806);
+    assert_eq!(
+        part1(parse(crate::util::data(2021, 17).unwrap()).unwrap()).unwrap(),
+        5886
+    );
+    assert_eq!(
+        part2(parse(crate::util::data(2021, 17).unwrap()).unwrap()).unwrap(),
+        1806
+    );
 }
diff --git a/src/2021/18/mod.rs b/src/2021/18/mod.rs
index e0616db..bd55f4d 100644
--- a/src/2021/18/mod.rs
+++ b/src/2021/18/mod.rs
@@ -1,7 +1,7 @@
 #![allow(clippy::collapsible_else_if)]
 
 #[derive(Clone)]
-enum Number {
+pub enum Number {
     Value(u8),
     Pair(Box<Number>, Box<Number>),
 }
@@ -210,14 +210,19 @@ impl std::fmt::Display for Number {
     }
 }
 
-pub fn part1() -> anyhow::Result<i64> {
-    let sum: Number = data_lines!()?.map(|line| Number::parse(&line)).sum();
+pub fn parse(
+    fh: std::fs::File,
+) -> anyhow::Result<impl Iterator<Item = Number>> {
+    Ok(crate::util::parse::lines(fh).map(|line| Number::parse(&line)))
+}
+
+pub fn part1(numbers: impl Iterator<Item = Number>) -> anyhow::Result<i64> {
+    let sum: Number = numbers.sum();
     Ok(sum.magnitude())
 }
 
-pub fn part2() -> anyhow::Result<i64> {
-    let nums: Vec<_> =
-        data_lines!()?.map(|line| Number::parse(&line)).collect();
+pub fn part2(numbers: impl Iterator<Item = Number>) -> anyhow::Result<i64> {
+    let nums: Vec<_> = numbers.collect();
     let mut max = 0;
     for (i, n1) in nums.iter().enumerate() {
         for (j, n2) in nums.iter().enumerate() {
@@ -235,6 +240,12 @@ pub fn part2() -> anyhow::Result<i64> {
 
 #[test]
 fn test() {
-    assert_eq!(part1().unwrap(), 3806);
-    assert_eq!(part2().unwrap(), 4727);
+    assert_eq!(
+        part1(parse(crate::util::data(2021, 18).unwrap()).unwrap()).unwrap(),
+        3806
+    );
+    assert_eq!(
+        part2(parse(crate::util::data(2021, 18).unwrap()).unwrap()).unwrap(),
+        4727
+    );
 }
diff --git a/src/2021/2/mod.rs b/src/2021/2/mod.rs
index e175ab9..6cac620 100644
--- a/src/2021/2/mod.rs
+++ b/src/2021/2/mod.rs
@@ -1,31 +1,60 @@
-pub fn part1() -> anyhow::Result<i64> {
-    let mut horizontal = 0;
-    let mut vertical = 0;
-    for line in data_lines!()? {
+pub enum Command {
+    Forward(i64),
+    Down(i64),
+    Up(i64),
+}
+
+pub fn parse(
+    fh: std::fs::File,
+) -> anyhow::Result<impl Iterator<Item = Command>> {
+    Ok(crate::util::parse::lines(fh).map(|line| {
         if let Some(n) = line.strip_prefix("forward ") {
-            horizontal += n.parse::<i64>()?;
+            Command::Forward(n.parse().unwrap())
         } else if let Some(n) = line.strip_prefix("down ") {
-            vertical += n.parse::<i64>()?;
+            Command::Down(n.parse().unwrap())
         } else if let Some(n) = line.strip_prefix("up ") {
-            vertical -= n.parse::<i64>()?;
+            Command::Up(n.parse().unwrap())
+        } else {
+            panic!("couldn't parse line: {}", line);
+        }
+    }))
+}
+
+pub fn part1(commands: impl Iterator<Item = Command>) -> anyhow::Result<i64> {
+    let mut horizontal = 0;
+    let mut vertical = 0;
+    for command in commands {
+        match command {
+            Command::Forward(n) => {
+                horizontal += n;
+            }
+            Command::Down(n) => {
+                vertical += n;
+            }
+            Command::Up(n) => {
+                vertical -= n;
+            }
         }
     }
     Ok(horizontal * vertical)
 }
 
-pub fn part2() -> anyhow::Result<i64> {
+pub fn part2(commands: impl Iterator<Item = Command>) -> anyhow::Result<i64> {
     let mut aim = 0;
     let mut horizontal = 0;
     let mut vertical = 0;
-    for line in data_lines!()? {
-        if let Some(n) = line.strip_prefix("forward ") {
-            let x = n.parse::<i64>()?;
-            horizontal += x;
-            vertical += aim * x;
-        } else if let Some(n) = line.strip_prefix("down ") {
-            aim += n.parse::<i64>()?;
-        } else if let Some(n) = line.strip_prefix("up ") {
-            aim -= n.parse::<i64>()?;
+    for command in commands {
+        match command {
+            Command::Forward(n) => {
+                horizontal += n;
+                vertical += aim * n;
+            }
+            Command::Down(n) => {
+                aim += n;
+            }
+            Command::Up(n) => {
+                aim -= n;
+            }
         }
     }
     Ok(horizontal * vertical)
@@ -33,6 +62,12 @@ pub fn part2() -> anyhow::Result<i64> {
 
 #[test]
 fn test() {
-    assert_eq!(part1().unwrap(), 1694130);
-    assert_eq!(part2().unwrap(), 1698850445);
+    assert_eq!(
+        part1(parse(crate::util::data(2021, 2).unwrap()).unwrap()).unwrap(),
+        1694130
+    );
+    assert_eq!(
+        part2(parse(crate::util::data(2021, 2).unwrap()).unwrap()).unwrap(),
+        1698850445
+    );
 }
diff --git a/src/2021/3/mod.rs b/src/2021/3/mod.rs
index a0fc64e..220ce33 100644
--- a/src/2021/3/mod.rs
+++ b/src/2021/3/mod.rs
@@ -1,5 +1,11 @@
-pub fn part1() -> anyhow::Result<i64> {
-    let (total_lines, by_pos) = pos_counts(data_lines!()?)?;
+pub fn parse(
+    fh: std::fs::File,
+) -> anyhow::Result<impl Iterator<Item = String>> {
+    Ok(crate::util::parse::lines(fh))
+}
+
+pub fn part1(lines: impl Iterator<Item = String>) -> anyhow::Result<i64> {
+    let (total_lines, by_pos) = pos_counts(lines)?;
     let gamma: String = by_pos
         .iter()
         .map(|pos| if pos * 2 >= total_lines { '1' } else { '0' })
@@ -11,8 +17,8 @@ pub fn part1() -> anyhow::Result<i64> {
     Ok(bin_str_to_int(&gamma) * bin_str_to_int(&epsilon))
 }
 
-pub fn part2() -> anyhow::Result<i64> {
-    let mut oxygen: Vec<_> = data_lines!()?.collect();
+pub fn part2(lines: impl Iterator<Item = String>) -> anyhow::Result<i64> {
+    let mut oxygen: Vec<_> = lines.collect();
     for i in 0..oxygen[0].len() {
         if oxygen.len() == 1 {
             break;
@@ -84,6 +90,12 @@ fn bin_str_to_int(s: &str) -> i64 {
 
 #[test]
 fn test() {
-    assert_eq!(part1().unwrap(), 3009600);
-    assert_eq!(part2().unwrap(), 6940518);
+    assert_eq!(
+        part1(parse(crate::util::data(2021, 3).unwrap()).unwrap()).unwrap(),
+        3009600
+    );
+    assert_eq!(
+        part2(parse(crate::util::data(2021, 3).unwrap()).unwrap()).unwrap(),
+        6940518
+    );
 }
diff --git a/src/2021/4/mod.rs b/src/2021/4/mod.rs
index 421ad67..c3bd7d8 100644
--- a/src/2021/4/mod.rs
+++ b/src/2021/4/mod.rs
@@ -51,7 +51,7 @@ impl Board {
 }
 
 #[derive(Debug)]
-struct Game {
+pub struct Game {
     inputs: Vec<u8>,
     boards: Vec<Board>,
 }
@@ -133,8 +133,11 @@ impl Game {
     }
 }
 
-pub fn part1() -> anyhow::Result<i64> {
-    let game = Game::parse(data!()?)?;
+pub fn parse(fh: std::fs::File) -> anyhow::Result<Game> {
+    Game::parse(fh)
+}
+
+pub fn part1(game: Game) -> anyhow::Result<i64> {
     if let Some((n, board)) = game.find_first_winner() {
         Ok((n as i64) * board.value())
     } else {
@@ -142,8 +145,7 @@ pub fn part1() -> anyhow::Result<i64> {
     }
 }
 
-pub fn part2() -> anyhow::Result<i64> {
-    let game = Game::parse(data!()?)?;
+pub fn part2(game: Game) -> anyhow::Result<i64> {
     if let Some((n, board)) = game.find_last_winner() {
         Ok((n as i64) * board.value())
     } else {
@@ -153,6 +155,12 @@ pub fn part2() -> anyhow::Result<i64> {
 
 #[test]
 fn test() {
-    assert_eq!(part1().unwrap(), 2745);
-    assert_eq!(part2().unwrap(), 6594);
+    assert_eq!(
+        part1(parse(crate::util::data(2021, 4).unwrap()).unwrap()).unwrap(),
+        2745
+    );
+    assert_eq!(
+        part2(parse(crate::util::data(2021, 4).unwrap()).unwrap()).unwrap(),
+        6594
+    );
 }
diff --git a/src/2021/5/mod.rs b/src/2021/5/mod.rs
index 229ba20..2e81e34 100644
--- a/src/2021/5/mod.rs
+++ b/src/2021/5/mod.rs
@@ -72,34 +72,37 @@ impl Map {
     }
 }
 
-pub fn part1() -> anyhow::Result<i64> {
-    let rx = regex::Regex::new("^(\\d+),(\\d+) -> (\\d+),(\\d+)$").unwrap();
-    let mut map = Map::default();
-    for line in data_lines!()? {
-        let nums: Vec<usize> = rx
-            .captures(&line)
+pub fn parse(
+    fh: std::fs::File,
+) -> anyhow::Result<impl Iterator<Item = Vec<usize>>> {
+    let rx = regex::Regex::new("^(\\d+),(\\d+) -> (\\d+),(\\d+)$")?;
+    Ok(crate::util::parse::lines(fh).map(move |line| {
+        rx.captures(&line)
             .unwrap()
             .iter()
             .skip(1)
             .map(|s| s.unwrap().as_str().parse())
-            .collect::<Result<_, _>>()?;
+            .collect::<Result<_, _>>()
+            .unwrap()
+    }))
+}
+
+pub fn part1(
+    coords: impl Iterator<Item = Vec<usize>>,
+) -> anyhow::Result<i64> {
+    let mut map = Map::default();
+    for nums in coords {
         let _ = map.mark_horizontal(nums[0], nums[1], nums[2], nums[3])
             || map.mark_vertical(nums[0], nums[1], nums[2], nums[3]);
     }
     Ok(map.count_overlapping().try_into()?)
 }
 
-pub fn part2() -> anyhow::Result<i64> {
-    let rx = regex::Regex::new("^(\\d+),(\\d+) -> (\\d+),(\\d+)$").unwrap();
+pub fn part2(
+    coords: impl Iterator<Item = Vec<usize>>,
+) -> anyhow::Result<i64> {
     let mut map = Map::default();
-    for line in data_lines!()? {
-        let nums: Vec<usize> = rx
-            .captures(&line)
-            .unwrap()
-            .iter()
-            .skip(1)
-            .map(|s| s.unwrap().as_str().parse())
-            .collect::<Result<_, _>>()?;
+    for nums in coords {
         let _ = map.mark_horizontal(nums[0], nums[1], nums[2], nums[3])
             || map.mark_vertical(nums[0], nums[1], nums[2], nums[3])
             || map.mark_diagonal(nums[0], nums[1], nums[2], nums[3])
@@ -110,6 +113,12 @@ pub fn part2() -> anyhow::Result<i64> {
 
 #[test]
 fn test() {
-    assert_eq!(part1().unwrap(), 6311);
-    assert_eq!(part2().unwrap(), 19929);
+    assert_eq!(
+        part1(parse(crate::util::data(2021, 5).unwrap()).unwrap()).unwrap(),
+        6311
+    );
+    assert_eq!(
+        part2(parse(crate::util::data(2021, 5).unwrap()).unwrap()).unwrap(),
+        19929
+    );
 }
diff --git a/src/2021/6/mod.rs b/src/2021/6/mod.rs
index 821e777..353aa8f 100644
--- a/src/2021/6/mod.rs
+++ b/src/2021/6/mod.rs
@@ -1,5 +1,11 @@
-pub fn part1() -> anyhow::Result<i64> {
-    let mut fishes: Vec<_> = data_ints!(b',')?.collect();
+pub fn parse(fh: std::fs::File) -> anyhow::Result<Vec<i64>> {
+    Ok(
+        crate::util::parse::ints(crate::util::parse::split(fh, b','))
+            .collect(),
+    )
+}
+
+pub fn part1(mut fishes: Vec<i64>) -> anyhow::Result<i64> {
     for _ in 0..80 {
         let mut new = 0;
         for fish in fishes.iter_mut() {
@@ -15,8 +21,7 @@ pub fn part1() -> anyhow::Result<i64> {
     Ok(fishes.len().try_into()?)
 }
 
-pub fn part2() -> anyhow::Result<i64> {
-    let fishes: Vec<_> = data_ints!(b',')?.collect();
+pub fn part2(fishes: Vec<i64>) -> anyhow::Result<i64> {
     let mut by_age = std::collections::VecDeque::new();
     by_age.resize(9, 0);
     for fish in fishes {
@@ -32,6 +37,12 @@ pub fn part2() -> anyhow::Result<i64> {
 
 #[test]
 fn test() {
-    assert_eq!(part1().unwrap(), 379114);
-    assert_eq!(part2().unwrap(), 1702631502303);
+    assert_eq!(
+        part1(parse(crate::util::data(2021, 6).unwrap()).unwrap()).unwrap(),
+        379114
+    );
+    assert_eq!(
+        part2(parse(crate::util::data(2021, 6).unwrap()).unwrap()).unwrap(),
+        1702631502303
+    );
 }
diff --git a/src/2021/7/mod.rs b/src/2021/7/mod.rs
index 1d8320a..ce942dc 100644
--- a/src/2021/7/mod.rs
+++ b/src/2021/7/mod.rs
@@ -1,5 +1,11 @@
-pub fn part1() -> anyhow::Result<i64> {
-    let crabs: Vec<_> = data_ints!(b',')?.collect();
+pub fn parse(fh: std::fs::File) -> anyhow::Result<Vec<i64>> {
+    Ok(
+        crate::util::parse::ints(crate::util::parse::split(fh, b','))
+            .collect(),
+    )
+}
+
+pub fn part1(crabs: Vec<i64>) -> anyhow::Result<i64> {
     Ok((0..=crabs.iter().copied().max().unwrap())
         .map(|start| {
             crabs.iter().copied().map(|crab| (crab - start).abs()).sum()
@@ -8,8 +14,7 @@ pub fn part1() -> anyhow::Result<i64> {
         .unwrap())
 }
 
-pub fn part2() -> anyhow::Result<i64> {
-    let crabs: Vec<_> = data_ints!(b',')?.collect();
+pub fn part2(crabs: Vec<i64>) -> anyhow::Result<i64> {
     Ok((0..=crabs.iter().copied().max().unwrap())
         .map(|start| {
             crabs
@@ -27,6 +32,12 @@ pub fn part2() -> anyhow::Result<i64> {
 
 #[test]
 fn test() {
-    assert_eq!(part1().unwrap(), 333755);
-    assert_eq!(part2().unwrap(), 94017638);
+    assert_eq!(
+        part1(parse(crate::util::data(2021, 7).unwrap()).unwrap()).unwrap(),
+        333755
+    );
+    assert_eq!(
+        part2(parse(crate::util::data(2021, 7).unwrap()).unwrap()).unwrap(),
+        94017638
+    );
 }
diff --git a/src/2021/8/mod.rs b/src/2021/8/mod.rs
index 7244524..8544247 100644
--- a/src/2021/8/mod.rs
+++ b/src/2021/8/mod.rs
@@ -1,10 +1,22 @@
-pub fn part1() -> anyhow::Result<i64> {
+pub fn parse(
+    fh: std::fs::File,
+) -> anyhow::Result<impl Iterator<Item = (Vec<String>, Vec<String>)>> {
+    Ok(crate::util::parse::lines(fh).map(|line| {
+        let parts: Vec<_> = line.split(" | ").collect();
+        (
+            parts[0].split(' ').map(str::to_string).collect(),
+            parts[1].split(' ').map(str::to_string).collect(),
+        )
+    }))
+}
+
+pub fn part1(
+    lines: impl Iterator<Item = (Vec<String>, Vec<String>)>,
+) -> anyhow::Result<i64> {
     let mut count = 0i64;
-    for line in data_lines!()? {
-        let mut parts = line.split(" | ");
-        let output = parts.nth(1).unwrap();
+    for (_, output) in lines {
         let line_count: i64 = output
-            .split(' ')
+            .iter()
             .filter(|s| [2, 3, 4, 7].contains(&s.len()))
             .count()
             .try_into()
@@ -21,13 +33,11 @@ pub fn part1() -> anyhow::Result<i64> {
 // 4  5
 // 4  5
 //  66
-pub fn part2() -> anyhow::Result<i64> {
+pub fn part2(
+    lines: impl Iterator<Item = (Vec<String>, Vec<String>)>,
+) -> anyhow::Result<i64> {
     let mut total = 0;
-    for line in data_lines!()? {
-        let mut parts = line.split(" | ");
-        let numbers = parts.next().unwrap();
-        let numbers: Vec<_> = numbers.split(' ').collect();
-
+    for (numbers, output) in lines {
         let mut segments = ['x'; 7];
 
         // zero: 6
@@ -150,9 +160,8 @@ pub fn part2() -> anyhow::Result<i64> {
         let numbers =
             [zero, one, two, three, four, five, six, seven, eight, nine];
 
-        let output = parts.next().unwrap();
         let value: Vec<_> = output
-            .split(' ')
+            .iter()
             .map(|s| s.chars().collect::<std::collections::HashSet<_>>())
             .map(|set| numbers.iter().position(|num| &set == num).unwrap())
             .collect();
@@ -165,6 +174,12 @@ pub fn part2() -> anyhow::Result<i64> {
 
 #[test]
 fn test() {
-    assert_eq!(part1().unwrap(), 355);
-    assert_eq!(part2().unwrap(), 983030);
+    assert_eq!(
+        part1(parse(crate::util::data(2021, 8).unwrap()).unwrap()).unwrap(),
+        355
+    );
+    assert_eq!(
+        part2(parse(crate::util::data(2021, 8).unwrap()).unwrap()).unwrap(),
+        983030
+    );
 }
diff --git a/src/2021/9/mod.rs b/src/2021/9/mod.rs
index 7c937a5..184c245 100644
--- a/src/2021/9/mod.rs
+++ b/src/2021/9/mod.rs
@@ -1,7 +1,12 @@
 use crate::util::grid::*;
 
-pub fn part1() -> anyhow::Result<i64> {
-    let map = data_digit_grid!();
+pub fn parse(fh: std::fs::File) -> anyhow::Result<Grid<u8>> {
+    Ok(crate::util::parse::digit_grid(crate::util::parse::lines(
+        fh,
+    )))
+}
+
+pub fn part1(map: Grid<u8>) -> anyhow::Result<i64> {
     let mut risk = 0;
     for ((row, col), pos) in map.indexed_cells() {
         if map
@@ -15,8 +20,7 @@ pub fn part1() -> anyhow::Result<i64> {
     Ok(risk)
 }
 
-pub fn part2() -> anyhow::Result<i64> {
-    let map = data_digit_grid!();
+pub fn part2(map: Grid<u8>) -> anyhow::Result<i64> {
     let mut low = vec![];
     for ((row, col), pos) in map.indexed_cells() {
         if map
@@ -58,6 +62,12 @@ pub fn part2() -> anyhow::Result<i64> {
 
 #[test]
 fn test() {
-    assert_eq!(part1().unwrap(), 570);
-    assert_eq!(part2().unwrap(), 899392);
+    assert_eq!(
+        part1(parse(crate::util::data(2021, 9).unwrap()).unwrap()).unwrap(),
+        570
+    );
+    assert_eq!(
+        part2(parse(crate::util::data(2021, 9).unwrap()).unwrap()).unwrap(),
+        899392
+    );
 }
diff --git a/src/2021/mod.rs b/src/2021/mod.rs
index b66f03e..507251e 100644
--- a/src/2021/mod.rs
+++ b/src/2021/mod.rs
@@ -38,42 +38,42 @@ mod day18;
 
 pub fn run(day: u8, puzzle: u8) -> anyhow::Result<i64> {
     match (day, puzzle) {
-        (1, 1) => day1::part1(),
-        (1, 2) => day1::part2(),
-        (2, 1) => day2::part1(),
-        (2, 2) => day2::part2(),
-        (3, 1) => day3::part1(),
-        (3, 2) => day3::part2(),
-        (4, 1) => day4::part1(),
-        (4, 2) => day4::part2(),
-        (5, 1) => day5::part1(),
-        (5, 2) => day5::part2(),
-        (6, 1) => day6::part1(),
-        (6, 2) => day6::part2(),
-        (7, 1) => day7::part1(),
-        (7, 2) => day7::part2(),
-        (8, 1) => day8::part1(),
-        (8, 2) => day8::part2(),
-        (9, 1) => day9::part1(),
-        (9, 2) => day9::part2(),
-        (10, 1) => day10::part1(),
-        (10, 2) => day10::part2(),
-        (11, 1) => day11::part1(),
-        (11, 2) => day11::part2(),
-        (12, 1) => day12::part1(),
-        (12, 2) => day12::part2(),
-        (13, 1) => day13::part1(),
-        (13, 2) => day13::part2(),
-        (14, 1) => day14::part1(),
-        (14, 2) => day14::part2(),
-        (15, 1) => day15::part1(),
-        (15, 2) => day15::part2(),
-        (16, 1) => day16::part1(),
-        (16, 2) => day16::part2(),
-        (17, 1) => day17::part1(),
-        (17, 2) => day17::part2(),
-        (18, 1) => day18::part1(),
-        (18, 2) => day18::part2(),
+        (1, 1) => day1::part1(day1::parse(crate::util::data(2021, 1)?)?),
+        (1, 2) => day1::part2(day1::parse(crate::util::data(2021, 1)?)?),
+        (2, 1) => day2::part1(day2::parse(crate::util::data(2021, 2)?)?),
+        (2, 2) => day2::part2(day2::parse(crate::util::data(2021, 2)?)?),
+        (3, 1) => day3::part1(day3::parse(crate::util::data(2021, 3)?)?),
+        (3, 2) => day3::part2(day3::parse(crate::util::data(2021, 3)?)?),
+        (4, 1) => day4::part1(day4::parse(crate::util::data(2021, 4)?)?),
+        (4, 2) => day4::part2(day4::parse(crate::util::data(2021, 4)?)?),
+        (5, 1) => day5::part1(day5::parse(crate::util::data(2021, 5)?)?),
+        (5, 2) => day5::part2(day5::parse(crate::util::data(2021, 5)?)?),
+        (6, 1) => day6::part1(day6::parse(crate::util::data(2021, 6)?)?),
+        (6, 2) => day6::part2(day6::parse(crate::util::data(2021, 6)?)?),
+        (7, 1) => day7::part1(day7::parse(crate::util::data(2021, 7)?)?),
+        (7, 2) => day7::part2(day7::parse(crate::util::data(2021, 7)?)?),
+        (8, 1) => day8::part1(day8::parse(crate::util::data(2021, 8)?)?),
+        (8, 2) => day8::part2(day8::parse(crate::util::data(2021, 8)?)?),
+        (9, 1) => day9::part1(day9::parse(crate::util::data(2021, 9)?)?),
+        (9, 2) => day9::part2(day9::parse(crate::util::data(2021, 9)?)?),
+        (10, 1) => day10::part1(day10::parse(crate::util::data(2021, 10)?)?),
+        (10, 2) => day10::part2(day10::parse(crate::util::data(2021, 10)?)?),
+        (11, 1) => day11::part1(day11::parse(crate::util::data(2021, 11)?)?),
+        (11, 2) => day11::part2(day11::parse(crate::util::data(2021, 11)?)?),
+        (12, 1) => day12::part1(day12::parse(crate::util::data(2021, 12)?)?),
+        (12, 2) => day12::part2(day12::parse(crate::util::data(2021, 12)?)?),
+        (13, 1) => day13::part1(day13::parse(crate::util::data(2021, 13)?)?),
+        (13, 2) => day13::part2(day13::parse(crate::util::data(2021, 13)?)?),
+        (14, 1) => day14::part1(day14::parse(crate::util::data(2021, 14)?)?),
+        (14, 2) => day14::part2(day14::parse(crate::util::data(2021, 14)?)?),
+        (15, 1) => day15::part1(day15::parse(crate::util::data(2021, 15)?)?),
+        (15, 2) => day15::part2(day15::parse(crate::util::data(2021, 15)?)?),
+        (16, 1) => day16::part1(day16::parse(crate::util::data(2021, 16)?)?),
+        (16, 2) => day16::part2(day16::parse(crate::util::data(2021, 16)?)?),
+        (17, 1) => day17::part1(day17::parse(crate::util::data(2021, 17)?)?),
+        (17, 2) => day17::part2(day17::parse(crate::util::data(2021, 17)?)?),
+        (18, 1) => day18::part1(day18::parse(crate::util::data(2021, 18)?)?),
+        (18, 2) => day18::part2(day18::parse(crate::util::data(2021, 18)?)?),
         // NEXT PART
         _ => Err(anyhow::anyhow!("unknown puzzle {}-{}", day, puzzle)),
     }
diff --git a/src/util.rs b/src/util.rs
index f60e78d..0bd31e5 100644
--- a/src/util.rs
+++ b/src/util.rs
@@ -5,3 +5,8 @@
 pub mod parse;
 
 pub mod grid;
+
+pub fn data(year: u16, day: u16) -> anyhow::Result<std::fs::File> {
+    std::fs::File::open(format!("data/{}/{}.txt", year, day))
+        .map_err(|e| anyhow::anyhow!(e))
+}
diff --git a/src/util/parse.rs b/src/util/parse.rs
index 08d35cc..5f42565 100644
--- a/src/util/parse.rs
+++ b/src/util/parse.rs
@@ -17,10 +17,13 @@ macro_rules! data_lines {
 
 macro_rules! data_ints {
     () => {
-        data!().map(|fh| crate::util::parse::ints_by_line(fh))
+        data!()
+            .map(|fh| crate::util::parse::ints(crate::util::parse::lines(fh)))
     };
     ($sep:expr) => {
-        data!().map(|fh| crate::util::parse::ints_by_split(fh, $sep))
+        data!().map(|fh| {
+            crate::util::parse::ints(crate::util::parse::split(fh, $sep))
+        })
     };
 }
 
@@ -62,24 +65,14 @@ pub fn lines(fh: std::fs::File) -> impl Iterator<Item = String> {
     fh.lines().map(|res| res.unwrap())
 }
 
-pub fn ints_by_line(fh: std::fs::File) -> impl Iterator<Item = i64> {
-    lines(fh).map(|l| l.parse().unwrap())
+pub fn split(fh: std::fs::File, sep: u8) -> impl Iterator<Item = String> {
+    let fh = std::io::BufReader::new(fh);
+    fh.split(sep)
+        .map(|res| String::from_utf8(res.unwrap()).unwrap())
 }
 
-pub fn ints_by_split(
-    fh: std::fs::File,
-    sep: u8,
-) -> impl Iterator<Item = i64> {
-    let fh = std::io::BufReader::new(fh);
-    fh.split(sep).filter_map(|res| {
-        let res = res.unwrap();
-        let s = std::str::from_utf8(&res).unwrap().trim();
-        if s.is_empty() {
-            None
-        } else {
-            Some(s.parse().unwrap())
-        }
-    })
+pub fn ints(iter: impl Iterator<Item = String>) -> impl Iterator<Item = i64> {
+    iter.map(|s| s.trim().parse().unwrap())
 }
 
 pub fn bytes(fh: std::fs::File) -> impl Iterator<Item = u8> {
@@ -88,7 +81,7 @@ pub fn bytes(fh: std::fs::File) -> impl Iterator<Item = u8> {
 
 pub fn string(fh: std::fs::File) -> String {
     let bytes: Vec<_> = bytes(fh).collect();
-    std::string::String::from_utf8(bytes).unwrap()
+    String::from_utf8(bytes).unwrap()
 }
 
 pub fn bool_grid(