From c083395455b8ddcbce9cab89c0e41e7f0e9d1846 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Alexander=20W=C3=BChr?= <alex@pnyhf.eu>
Date: Fri, 13 Sep 2024 08:56:20 +0200
Subject: [PATCH] feat(iterator): implement `iterator_from_string` (closes #3)

---
 manifest.toml         | 11 +++++++++++
 src/brilo.gleam       | 24 +++++++++++++++++++++---
 test/brilo_test.gleam | 15 +++++++++++----
 3 files changed, 43 insertions(+), 7 deletions(-)
 create mode 100644 manifest.toml

diff --git a/manifest.toml b/manifest.toml
new file mode 100644
index 0000000..e851620
--- /dev/null
+++ b/manifest.toml
@@ -0,0 +1,11 @@
+# This file was generated by Gleam
+# You typically do not need to edit this file
+
+packages = [
+  { name = "gleam_stdlib", version = "0.40.0", build_tools = ["gleam"], requirements = [], otp_app = "gleam_stdlib", source = "hex", outer_checksum = "86606B75A600BBD05E539EB59FABC6E307EEEA7B1E5865AFB6D980A93BCB2181" },
+  { name = "gleeunit", version = "1.2.0", build_tools = ["gleam"], requirements = ["gleam_stdlib"], otp_app = "gleeunit", source = "hex", outer_checksum = "F7A7228925D3EE7D0813C922E062BFD6D7E9310F0BEE585D3A42F3307E3CFD13" },
+]
+
+[requirements]
+gleam_stdlib = { version = ">= 0.34.0 and < 2.0.0" }
+gleeunit = { version = ">= 1.0.0 and < 2.0.0" }
diff --git a/src/brilo.gleam b/src/brilo.gleam
index ca67592..6168981 100644
--- a/src/brilo.gleam
+++ b/src/brilo.gleam
@@ -1,5 +1,23 @@
-import gleam/io
+import gleam/iterator.{type Iterator, Done, Next}
+import gleam/string
 
-pub fn main() {
-  io.println("Hello from brilo!")
+/// Creates an iterator that yields each grapheme from the given string.
+///
+/// ## Examples
+///
+/// ```gleam
+/// iterator_from_string("abcd")
+/// |> to_list
+/// // -> ["a", "b", "c", "d"]
+/// ```
+///
+pub fn iterator_from_string(string: String) -> Iterator(String) {
+  let yield = fn(s) {
+    case s |> string.pop_grapheme {
+      Ok(#(x, xs)) -> Next(x, xs)
+      _ -> Done
+    }
+  }
+
+  iterator.unfold(from: string, with: yield)
 }
diff --git a/test/brilo_test.gleam b/test/brilo_test.gleam
index 3831e7a..627252e 100644
--- a/test/brilo_test.gleam
+++ b/test/brilo_test.gleam
@@ -1,3 +1,6 @@
+import brilo
+import gleam/iterator
+import gleam/string
 import gleeunit
 import gleeunit/should
 
@@ -5,8 +8,12 @@ pub fn main() {
   gleeunit.main()
 }
 
-// gleeunit test functions end in `_test`
-pub fn hello_world_test() {
-  1
-  |> should.equal(1)
+pub fn iterator_from_string_test() {
+  let string = "BRILO RULEZ! 🎆"
+
+  string
+  |> brilo.iterator_from_string
+  |> iterator.to_list
+  |> string.join("")
+  |> should.equal(string)
 }