Solve day 1 of 2020 in Gleam

2 files changed, 58 insertions, 0 deletions

diff --git a/aoc-2020-gleam/src/util/input_util.gleam b/aoc-2020-gleam/src/util/input_util.gleam
new file mode 100644
index 0000000..3e6b076
--- /dev/null
+++ b/aoc-2020-gleam/src/util/input_util.gleam
@@ -0,0 +1,26 @@
+import gleam/list
+import gleam/string
+import gleam/erlang/file
+import ext/intx
+import ext/stringx
+import ext/resultx
+
+pub fn read_text(filename: String) -> String {
+  "data/" <> filename <> ".txt"
+  |> file.read()
+  |> resultx.force_unwrap()
+}
+
+pub fn read_lines(filename: String) -> List(String) {
+  filename
+  |> read_text()
+  |> string.split(on: "\n")
+  |> list.map(with: string.trim)
+  |> list.filter(for: stringx.is_not_empty)
+}
+
+pub fn read_numbers(filename: String) -> List(Int) {
+  filename
+  |> read_lines()
+  |> list.map(with: intx.force_parse)
+}
diff --git a/aoc-2020-gleam/src/util/runner.gleam b/aoc-2020-gleam/src/util/runner.gleam
new file mode 100644
index 0000000..0ff0a41
--- /dev/null
+++ b/aoc-2020-gleam/src/util/runner.gleam
@@ -0,0 +1,32 @@
+import gleam/list
+import gleam/int
+import gleam/io
+import gleam/result
+import gleam/erlang.{start_arguments}
+
+fn get_day(handler: fn(Int) -> Nil) -> Result(Nil, String) {
+  let args = start_arguments()
+
+  use first <- result.then(
+    args
+    |> list.first()
+    |> result.replace_error("Pass the day as first argument!"),
+  )
+
+  use day <- result.then(
+    first
+    |> int.parse()
+    |> result.replace_error("The day argument must be a number!"),
+  )
+
+  handler(day)
+
+  Ok(Nil)
+}
+
+pub fn with_day(handler: fn(Int) -> Nil) -> Nil {
+  handler
+  |> get_day()
+  |> result.map_error(io.println)
+  |> result.unwrap(Nil)
+}