57 lines
1.4 KiB
Zig
57 lines
1.4 KiB
Zig
//
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// Let's revisit the very first error exercise. This time, we're going to
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// look at an error-handling variation of the "if" statement.
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//
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// if (foo) |value| {
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//
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// // foo was NOT an error; value is the non-error value of foo
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//
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// } else |err| {
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//
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// // foo WAS an error; err is the error value of foo
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//
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// }
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//
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// We'll take it even further and use a switch statement to handle
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// the error types.
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//
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// if (foo) |value| {
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// ...
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// } else |err| switch(err) {
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// ...
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// }
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//
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const MyNumberError = error{
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TooBig,
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TooSmall,
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};
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const std = @import("std");
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pub fn main() void {
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const nums = [_]u8{ 2, 3, 4, 5, 6 };
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for (nums) |num| {
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std.debug.print("{}", .{num});
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const n = numberMaybeFail(num);
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if (n) |value| {
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std.debug.print("={}. ", .{value});
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} else |err| switch (err) {
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MyNumberError.TooBig => std.debug.print(">4. ", .{}),
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// Please add a match for TooSmall here and have it print: "<4. "
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MyNumberError.TooSmall => std.debug.print("<4. ", .{}),
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}
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}
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std.debug.print("\n", .{});
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}
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// This time we'll have numberMaybeFail() return an error union rather
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// than a straight error.
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fn numberMaybeFail(n: u8) MyNumberError!u8 {
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if (n > 4) return MyNumberError.TooBig;
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if (n < 4) return MyNumberError.TooSmall;
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return n;
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}
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