add ex084 async

This commit is contained in:
Dave Gauer 2021-05-12 20:35:29 -04:00
parent 03eb291d39
commit 3b08761532
4 changed files with 67 additions and 5 deletions

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@ -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

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@ -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.

56
exercises/084_async.zig Normal file
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@ -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", .{});
}

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@ -0,0 +1,4 @@
49c49
< foo();
---
> var foo_frame = async foo();