add ex090 async 7

1 files changed, 43 insertions, 0 deletions

diff --git a/exercises/090_async7.zig b/exercises/090_async7.zig
new file mode 100644
index 0000000..89113bd
--- /dev/null
+++ b/exercises/090_async7.zig
@@ -0,0 +1,43 @@
+//
+// Remember how a function with 'suspend' is async and calling an
+// async function without the 'async' keyword makes the CALLING
+// function async?
+//
+//     fn fooThatMightSuspend(maybe: bool) void {
+//         if (maybe) suspend {}
+//     }
+//
+//     fn bar() void {
+//         fooThatMightSuspend(true); // Now bar() is async!
+//     }
+// 
+// But if you KNOW the function won't suspend, you can make a
+// promise to the compiler with the 'nosuspend' keyword:
+//
+//     fn bar() void {
+//         nosuspend fooThatMightSuspend(false);
+//     }
+//
+// If the function does suspend and YOUR PROMISE TO THE COMPILER
+// IS BROKEN, the program will panic at runtime, which is
+// probably better than you deserve, you oathbreaker! >:-(
+//
+const print = @import("std").debug.print;
+
+pub fn main() void {
+
+    // The main() function can not be async. But we know
+    // getBeef() will not suspend with this particular
+    // invocation. Please make this okay:
+    var my_beef = getBeef(0);
+
+    print("beef? {X}!\n", .{my_beef});
+}
+
+fn getBeef(input: u32) u32 {
+    if (input > 0xDEAD) {
+        suspend {}
+    }
+
+    return 0xBEEF;
+}