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const std = @import("std");
const builtin = @import("builtin");
const expect = std.testing.expect;
test "switch simple" {
const a: u64 = 10;
const zz: u64 = 103;
// All branches of a switch expression must be able to be coerced to a
// common type.
//
// Branches cannot fallthrough. If fallthrough behavior is desired, combine
// the cases and use an if.
const b = switch (a) {
// Multiple cases can be combined via a ','
1, 2, 3 => 0,
// Ranges can be specified using the ... syntax. These are inclusive
// of both ends.
5...100 => 1,
// Branches can be arbitrarily complex.
101 => blk: {
const c: u64 = 5;
break :blk c * 2 + 1;
},
// Switching on arbitrary expressions is allowed as long as the
// expression is known at compile-time.
zz => zz,
blk: {
const d: u32 = 5;
const e: u32 = 100;
break :blk d + e;
} => 107,
// The else branch catches everything not already captured.
// Else branches are mandatory unless the entire range of values
// is handled.
else => 9,
};
try expect(b == 1);
}
// Switch expressions can be used outside a function:
const os_msg = switch (builtin.target.os.tag) {
.linux => "we found a linux user",
else => "not a linux user",
};
// Inside a function, switch statements implicitly are compile-time
// evaluated if the target expression is compile-time known.
test "switch inside function" {
switch (builtin.target.os.tag) {
.fuchsia => {
// On an OS other than fuchsia, block is not even analyzed,
// so this compile error is not triggered.
// On fuchsia this compile error would be triggered.
@compileError("fuchsia not supported");
},
else => {},
}
}
// test
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