From 1c6487c1e79cbe0d59a39b483af8ec44b59c586e Mon Sep 17 00:00:00 2001
From: Chris Boesch <chrboesch@noreply.codeberg.org>
Date: Fri, 3 Apr 2026 18:11:00 +0200
Subject: added async-io quiz

---
 exercises/090_async6.zig | 71 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 71 insertions(+)
 create mode 100644 exercises/090_async6.zig

(limited to 'exercises/090_async6.zig')

diff --git a/exercises/090_async6.zig b/exercises/090_async6.zig
new file mode 100644
index 0000000..eab03c9
--- /dev/null
+++ b/exercises/090_async6.zig
@@ -0,0 +1,71 @@
+//
+// Sometimes you want to race multiple tasks and act on whichever
+// finishes first. That's what Select is for!
+//
+// Select is like a Group, but lets you receive individual results
+// as tasks complete — one at a time:
+//
+//     const Race = std.Io.Select(union(enum) {
+//         fast: u32,
+//         slow: u32,
+//     });
+//
+//     var buffer: [2]Race.Union = undefined;
+//     var sel = Race.init(io, &buffer);
+//
+//     sel.async(.fast, fastFn, .{io});
+//     sel.async(.slow, slowFn, .{io});
+//
+//     const winner = try sel.await();  // returns first completed
+//     switch (winner) {
+//         .fast => |val| ...,
+//         .slow => |val| ...,
+//     }
+//     sel.cancelDiscard();  // cancel remaining, discard results
+//
+// The buffer must be large enough for all tasks that might
+// complete before you call cancelDiscard().
+//
+// Fix this program to receive the winner of the race.
+//
+const std = @import("std");
+const print = std.debug.print;
+
+const RaceResult = std.Io.Select(union(enum) {
+    hare: []const u8,
+    tortoise: []const u8,
+});
+
+pub fn main(init: std.process.Init) !void {
+    const io = init.io;
+
+    var buffer: [2]RaceResult.Union = undefined;
+    var sel = RaceResult.init(io, &buffer);
+
+    sel.async(.hare, runHare, .{io});
+    sel.async(.tortoise, runTortoise, .{io});
+
+    // Wait for the first finisher.
+    // What Select method returns the first completed result?
+    const winner = ???;
+
+    switch (winner) {
+        .hare => |msg| print("Hare: {s}\n", .{msg}),
+        .tortoise => |msg| print("Tortoise: {s}\n", .{msg}),
+    }
+
+    // Clean up the loser — we don't need their result.
+    sel.cancelDiscard();
+}
+
+fn runHare(io: std.Io) []const u8 {
+    // The hare is fast — only 1 second!
+    io.sleep(std.Io.Duration.fromSeconds(1), .awake) catch return "I got canceled!";
+    return "I'm fast!";
+}
+
+fn runTortoise(io: std.Io) []const u8 {
+    // The tortoise is slow — 10 seconds.
+    io.sleep(std.Io.Duration.fromSeconds(10), .awake) catch return "I got canceled!";
+    return "Slow and steady...";
+}
-- 
cgit v1.2.3


From aeeb18931da3c8444fc85db4da43e72a0ad2a46a Mon Sep 17 00:00:00 2001
From: Chris Boesch <chrboesch@noreply.codeberg.org>
Date: Mon, 6 Apr 2026 18:50:57 +0200
Subject: improvements for async-io

---
 exercises/090_async6.zig         | 7 ++++++-
 patches/patches/090_async6.patch | 8 ++++----
 2 files changed, 10 insertions(+), 5 deletions(-)

(limited to 'exercises/090_async6.zig')

diff --git a/exercises/090_async6.zig b/exercises/090_async6.zig
index eab03c9..16fb75f 100644
--- a/exercises/090_async6.zig
+++ b/exercises/090_async6.zig
@@ -23,6 +23,11 @@
 //     }
 //     sel.cancelDiscard();  // cancel remaining, discard results
 //
+// As with all async primitives: tasks spawned in a Select MUST
+// be cleaned up. Use sel.cancel() to get remaining results one
+// by one (for resource cleanup), or sel.cancelDiscard() if you
+// don't need them.
+//
 // The buffer must be large enough for all tasks that might
 // complete before you call cancelDiscard().
 //
@@ -47,7 +52,7 @@ pub fn main(init: std.process.Init) !void {
 
     // Wait for the first finisher.
     // What Select method returns the first completed result?
-    const winner = ???;
+    const winner = try sel.???();
 
     switch (winner) {
         .hare => |msg| print("Hare: {s}\n", .{msg}),
diff --git a/patches/patches/090_async6.patch b/patches/patches/090_async6.patch
index 5ac777b..6289708 100644
--- a/patches/patches/090_async6.patch
+++ b/patches/patches/090_async6.patch
@@ -1,10 +1,10 @@
---- exercises/090_async6.zig	2026-04-02 10:25:34.016616118 +0200
-+++ answers/090_async6.zig	2026-04-02 10:27:48.827144051 +0200
-@@ -47,7 +47,7 @@
+--- exercises/090_async6.zig	2026-04-06 18:49:37.232023422 +0200
++++ answers/090_async6.zig	2026-04-06 18:49:22.189720687 +0200
+@@ -52,7 +52,7 @@
  
      // Wait for the first finisher.
      // What Select method returns the first completed result?
--    const winner = ???;
+-    const winner = try sel.???();
 +    const winner = try sel.await();
  
      switch (winner) {
-- 
cgit v1.2.3