add ex090 async 7
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commit
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//
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// Remember how a function with 'suspend' is async and calling an
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// async function without the 'async' keyword makes the CALLING
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// function async?
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//
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// fn fooThatMightSuspend(maybe: bool) void {
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// if (maybe) suspend {}
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// }
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//
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// fn bar() void {
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// fooThatMightSuspend(true); // Now bar() is async!
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// }
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//
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// But if you KNOW the function won't suspend, you can make a
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// promise to the compiler with the 'nosuspend' keyword:
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//
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// fn bar() void {
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// nosuspend fooThatMightSuspend(false);
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// }
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//
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// If the function does suspend and YOUR PROMISE TO THE COMPILER
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// IS BROKEN, the program will panic at runtime, which is
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// probably better than you deserve, you oathbreaker! >:-(
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//
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const print = @import("std").debug.print;
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pub fn main() void {
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// The main() function can not be async. But we know
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// getBeef() will not suspend with this particular
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// invocation. Please make this okay:
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var my_beef = getBeef(0);
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print("beef? {X}!\n", .{my_beef});
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}
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fn getBeef(input: u32) u32 {
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if (input > 0xDEAD) {
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suspend {}
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}
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return 0xBEEF;
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}
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@ -0,0 +1,4 @@
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32c32
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< var my_beef = getBeef(0);
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---
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> var my_beef = nosuspend getBeef(0);
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