11 files changed, 50 insertions, 27 deletions
diff --git a/aoc-2020-gleam/manifest.toml b/aoc-2020-gleam/manifest.toml
index 2b3dceb..e349bd0 100644
--- a/aoc-2020-gleam/manifest.toml
+++ b/aoc-2020-gleam/manifest.toml
@@ -2,8 +2,8 @@
 # You typically do not need to edit this file
 
 packages = [
-  { name = "gleam_erlang", version = "0.18.0", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "gleam_erlang", source = "hex", outer_checksum = "14ABC93A7975369CCDDC0C4D9A34C0E0FE99CA3AD336BE6A17299EC0285B7107" },
-  { name = "gleam_stdlib", version = "0.26.1", build_tools = ["gleam"], requirements = [], otp_app = "gleam_stdlib", source = "hex", outer_checksum = "B17BBE8A78F3909D93BCC6C24F531673A7E328A61F24222EB1E58D0A7552B1FE" },
+  { name = "gleam_erlang", version = "0.18.1", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "gleam_erlang", source = "hex", outer_checksum = "C69F59D086AD50B80DE294FB0963550630971C9DC04E92B1F7AEEDD2C0BE226C" },
+  { name = "gleam_stdlib", version = "0.27.0", build_tools = ["gleam"], requirements = [], otp_app = "gleam_stdlib", source = "hex", outer_checksum = "9DBDD21B48C654182CDD8AA15ACF85E8E74A0438583C68BD7EF08BE89F999C6F" },
 ]
 
 [requirements]
diff --git a/aoc-2020-gleam/src/days/day02.gleam b/aoc-2020-gleam/src/days/day02.gleam
index cedb604..530ab0f 100644
--- a/aoc-2020-gleam/src/days/day02.gleam
+++ b/aoc-2020-gleam/src/days/day02.gleam
@@ -3,6 +3,8 @@ import gleam/list
 import gleam/bool
 import gleam/string as str
 import ext/listx
+import ext/intx
+import ext/genericx as genx
 import ext/resultx as resx
 import util/input_util
 import util/parser as p
@@ -50,8 +52,8 @@ fn part1(lines: List(String)) -> Int {
     fn(line) {
       line.password
       |> str.to_graphemes
-      |> listx.count(satisfying: fn(g) { g == line.policy.grapheme })
-      |> fn(l) { line.policy.min <= l && l <= line.policy.max }
+      |> listx.count(satisfying: genx.equals(_, line.policy.grapheme))
+      |> intx.is_between(line.policy.min, and: line.policy.max)
     },
   )
 }
@@ -64,7 +66,8 @@ fn part2(lines: List(String)) -> Int {
         line.password
         |> str.to_graphemes
         |> list.at(index - 1)
-        |> resx.assert_unwrap == line.policy.grapheme
+        |> resx.assert_unwrap
+        |> genx.equals(line.policy.grapheme)
       }
       bool.exclusive_or(
         grapheme_matches(line.policy.min),
diff --git a/aoc-2020-gleam/src/days/day03.gleam b/aoc-2020-gleam/src/days/day03.gleam
index e4cecda..4c1ef59 100644
--- a/aoc-2020-gleam/src/days/day03.gleam
+++ b/aoc-2020-gleam/src/days/day03.gleam
@@ -5,6 +5,7 @@ import gleam/string as str
 import gleam/function as fun
 import gleam/iterator as iter
 import gleam/set.{Set}
+import ext/intx
 import ext/resultx as resx
 import ext/iteratorx as iterx
 import util/input_util
@@ -62,7 +63,7 @@ fn has_tree(in area: Area, at pos: Pos) -> Bool {
 }
 
 fn is_valid(pos: Pos, in area: Area) -> Bool {
-  0 <= pos.1 && pos.1 < area.height
+  intx.is_between(pos.1, 0, and: area.height - 1)
 }
 
 fn tree_count(in area: Area, with slope: Pos) -> Int {
diff --git a/aoc-2020-gleam/src/days/day04.gleam b/aoc-2020-gleam/src/days/day04.gleam
index 21998e2..305cfa1 100644
--- a/aoc-2020-gleam/src/days/day04.gleam
+++ b/aoc-2020-gleam/src/days/day04.gleam
@@ -4,6 +4,7 @@ import gleam/function as fun
 import gleam/result as res
 import gleam/map.{Map}
 import ext/listx
+import ext/intx
 import ext/resultx as resx
 import util/input_util
 import util/parser as p
@@ -61,7 +62,7 @@ fn is_valid1(passport: Passport) -> Bool {
 fn is_valid2(passport: Passport) -> Bool {
   let int_between = fn(min, max) {
     p.int()
-    |> p.satisfying(rule: fn(num) { min <= num && num <= max })
+    |> p.satisfying(rule: intx.is_between(_, min, and: max))
     |> p.ignore
   }
 
diff --git a/aoc-2020-gleam/src/days/day05.gleam b/aoc-2020-gleam/src/days/day05.gleam
index 8eeb94b..b3448a8 100644
--- a/aoc-2020-gleam/src/days/day05.gleam
+++ b/aoc-2020-gleam/src/days/day05.gleam
@@ -34,7 +34,7 @@ fn part2(lines: List(String)) -> Int {
     |> list.map(with: get_seat_id)
     |> set.from_list
 
-  let occupied = fn(id) { set.contains(in: seat_ids, this: id) }
+  let occupied = set.contains(in: seat_ids, this: _)
 
   iter.find(
     in: iter.range(from: 1, to: 1023),
diff --git a/aoc-2020-gleam/src/days/day07.gleam b/aoc-2020-gleam/src/days/day07.gleam
index 2e7c890..fb5949c 100644
--- a/aoc-2020-gleam/src/days/day07.gleam
+++ b/aoc-2020-gleam/src/days/day07.gleam
@@ -1,10 +1,12 @@
 import gleam/io
+import gleam/int
 import gleam/list
 import gleam/pair
 import gleam/result as res
 import gleam/function as fun
 import gleam/map.{Map}
 import gleam/iterator.{Iterator} as iter
+import ext/genericx as genx
 import ext/resultx as resx
 import ext/iteratorx as iterx
 import util/graph
@@ -85,16 +87,18 @@ fn part1(lines: List(String)) -> Int {
   graph
   |> map.keys
   |> iter.from_list
-  |> iter.filter(for: fn(bag) { bag != special_bag })
+  |> iter.filter(for: genx.different(_, than: special_bag))
   |> iterx.count(satisfying: fn(start) {
     start
     |> graph.dfs(with: neighbours)
-    |> iter.any(fn(bag) { bag == special_bag })
+    |> iter.any(satisfying: genx.equals(_, special_bag))
   })
 }
 
 fn part2(lines: List(String)) -> Int {
-  bag_count(of: special_bag, in: parse_graph(lines)) - 1
+  special_bag
+  |> bag_count(in: parse_graph(lines))
+  |> int.subtract(1)
 }
 
 pub fn run() -> Nil {
diff --git a/aoc-2020-gleam/src/days/day08.gleam b/aoc-2020-gleam/src/days/day08.gleam
index 6f074cf..9ef430b 100644
--- a/aoc-2020-gleam/src/days/day08.gleam
+++ b/aoc-2020-gleam/src/days/day08.gleam
@@ -1,5 +1,7 @@
 import gleam/io
+import gleam/int
 import gleam/list
+import gleam/bool
 import gleam/set.{Set}
 import gleam/iterator.{Iterator} as iter
 import gleam/option.{None, Option, Some} as opt
@@ -35,7 +37,7 @@ fn parse_program(lines: List(String)) -> Program {
       p.replace(p.literal("-"), with: -1),
     ])
     |> p.then(p.int())
-    |> p.map2(with: fn(sign, magnitude) { sign * magnitude })
+    |> p.map2(with: int.multiply)
 
   let instr_parser =
     p.any(of: [
@@ -77,10 +79,14 @@ fn execution_result_helper(
   cpu: Cpu,
   visited: Set(Int),
 ) -> ExecutionResult {
-  case set.contains(visited, cpu.pc), fetch(from: program, with: cpu) {
-    True, _ -> InfiniteLoop(acc_before_second: cpu.acc)
-    _, None -> Termination(acc_after: cpu.acc)
-    _, Some(instr) ->
+  use <- bool.guard(
+    when: set.contains(visited, cpu.pc),
+    return: InfiniteLoop(acc_before_second: cpu.acc),
+  )
+
+  case fetch(from: program, with: cpu) {
+    None -> Termination(acc_after: cpu.acc)
+    Some(instr) ->
       execution_result_helper(
         program,
         execute(instr, on: cpu),
diff --git a/aoc-2020-gleam/src/ext/genericx.gleam b/aoc-2020-gleam/src/ext/genericx.gleam
new file mode 100644
index 0000000..57ce450
--- /dev/null
+++ b/aoc-2020-gleam/src/ext/genericx.gleam
@@ -0,0 +1,7 @@
+pub fn equals(left: a, right: a) -> Bool {
+  left == right
+}
+
+pub fn different(left: a, than right: a) -> Bool {
+  left != right
+}
diff --git a/aoc-2020-gleam/src/ext/intx.gleam b/aoc-2020-gleam/src/ext/intx.gleam
new file mode 100644
index 0000000..9f06850
--- /dev/null
+++ b/aoc-2020-gleam/src/ext/intx.gleam
@@ -0,0 +1,3 @@
+pub fn is_between(number: Int, min: Int, and max: Int) {
+  min <= number && number <= max
+}
diff --git a/aoc-2020-gleam/src/ext/resultx.gleam b/aoc-2020-gleam/src/ext/resultx.gleam
index d354216..2067291 100644
--- a/aoc-2020-gleam/src/ext/resultx.gleam
+++ b/aoc-2020-gleam/src/ext/resultx.gleam
@@ -1,4 +1,6 @@
 pub fn assert_unwrap(result: Result(t, _)) -> t {
-  let assert Ok(value) = result
-  value
+  case result {
+    Ok(value) -> value
+    _ -> panic
+  }
 }
diff --git a/aoc-2020-gleam/src/util/parser.gleam b/aoc-2020-gleam/src/util/parser.gleam
index 1ca2447..f143c92 100644
--- a/aoc-2020-gleam/src/util/parser.gleam
+++ b/aoc-2020-gleam/src/util/parser.gleam
@@ -150,10 +150,8 @@ pub fn ignore(parser: Parser(a)) -> Parser(Nil) {
 
 pub fn then(first: Parser(a), second: Parser(b)) -> Parser(#(a, b)) {
   create(fn(input) {
-    use parsed1 <- res.then(run(first, on: input))
-    let #(value1, remaining1) = parsed1
-    use parsed2 <- res.then(run(second, on: remaining1))
-    let #(value2, remaining2) = parsed2
+    use #(value1, remaining1) <- res.then(run(first, on: input))
+    use #(value2, remaining2) <- res.then(run(second, on: remaining1))
     Ok(#(#(value1, value2), remaining2))
   })
   |> labeled(with: first.label <> " |> then(" <> second.label <> ")")
@@ -219,8 +217,7 @@ fn flat_map(
   with mapper: fn(a) -> Result(b, ParseError),
 ) -> Parser(b) {
   create(fn(input) {
-    use parsed <- res.then(run(parser, on: input))
-    let #(value, remaining) = parsed
+    use #(value, remaining) <- res.then(run(parser, on: input))
     value
     |> mapper
     |> res.map(with: fn(new_value) { #(new_value, remaining) })
@@ -248,7 +245,7 @@ fn succeeding(with value: a) -> Parser(a) {
 }
 
 fn failing(with error: ParseError) -> Parser(a) {
-  create(fn(_) { Error(error) })
+  create(fun.constant(Error(error)))
 }
 
 fn lift2(function: fn(a, b) -> c) -> fn(Parser(a), Parser(b)) -> Parser(c) {
@@ -308,8 +305,7 @@ pub fn str_of_many0(of parser: Parser(String)) -> Parser(String) {
 
 pub fn many1(of parser: Parser(a)) -> Parser(List(a)) {
   create(fn(input) {
-    use parsed <- res.then(run(parser, on: input))
-    let #(value, rest) = parsed
+    use #(value, rest) <- res.then(run(parser, on: input))
     let #(previous, rest) = do_zero_or_more(rest, with: parser)
     Ok(#([value, ..previous], rest))
   })