diff --git a/README.md b/README.md index 7a44cf0..44ceb22 100644 --- a/README.md +++ b/README.md @@ -149,10 +149,7 @@ Core Language * [x] Sentinel termination * [x] Quoted identifiers @"" * [x] Anonymous structs/tuples/lists -* [ ] Suspend / Resume -* [ ] Async / Await -* [ ] Nosuspend -* [ ] Async Frames, Suspend Blocks +* [ ] Async * [ ] Working with C? Modules and the Zig Standard Library diff --git a/build.zig b/build.zig index 1269a0e..fc831b8 100644 --- a/build.zig +++ b/build.zig @@ -407,12 +407,17 @@ const exercises = [_]Exercise{ .{ .main_file = "082_anonymous_structs3.zig", .output = "\"0\"(bool):true \"1\"(bool):false \"2\"(i32):42 \"3\"(f32):3.14159202e+00", - .hint = "This one is a challenge! But you have everything you need." + .hint = "This one is a challenge! But you have everything you need.", }, .{ .main_file = "083_anonymous_lists.zig", .output = "I say hello!", }, + .{ + .main_file = "084_async.zig", + .output = "foo() A", + .hint = "Read the facts. Use the facts.", + }, }; /// Check the zig version to make sure it can compile the examples properly. diff --git a/exercises/084_async.zig b/exercises/084_async.zig new file mode 100644 index 0000000..fe68b03 --- /dev/null +++ b/exercises/084_async.zig @@ -0,0 +1,56 @@ +// +// Six Facts: +// +// 1. The memory space allocated to your program for the +// invocation of a function and all of its data is called a +// "stack frame". +// +// 2. The 'return' keyword "pops" the current function +// invocation's frame off of the stack (it is no longer needed) +// and returns control to the place where the function was +// called. +// +// fn foo() void { +// return; // Pop the frame and return control +// } +// +// 3. Like 'return', the 'suspend' keyword returns control to the +// place where the function was called BUT the function +// invocation's frame remains so that it can regain control again +// at a later time. Functions which do this are "async" +// functions. +// +// fn fooThatSuspends() void { +// suspend; // return control, but leave the frame alone +// } +// +// 4. To call any function in async context and get a reference +// to its frame for later use, use the 'async' keyword: +// +// var foo_frame = async fooThatSuspends(); +// +// 5. If you call an async function without the 'async' keyword, +// the function FROM WHICH you called the async function itself +// becomes async! In this example, the bar() function is now +// async because it calls fooThatSuspends(), which is async. +// +// fn bar() void { +// fooThatSuspends(); +// } +// +// 6. The main() function cannot be async! +// +// Given facts 3 and 4, how do we fix this program (broken by facts +// 5 and 6)? +// +const print = @import("std").debug.print; + +pub fn main() void { + foo(); +} + +fn foo() void { + print("foo() A\n", .{}); + suspend; + print("foo() B\n", .{}); +} diff --git a/patches/patches/084_async.patch b/patches/patches/084_async.patch new file mode 100644 index 0000000..6164775 --- /dev/null +++ b/patches/patches/084_async.patch @@ -0,0 +1,4 @@ +49c49 +< foo(); +--- +> var foo_frame = async foo();