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//
// Remember that little mathematical virtual machine we made using the
// "unreachable" statement? Well, there were two problems with the
// way we were using op codes:
//
// 1. Having to remember op codes by number is no good.
// 2. We had to use "unreachable" because Zig had no way of knowing
// how many valid op codes there were.
//
// An "enum" is a Zig construct that lets you give names to numeric
// values and store them in a set. They look a lot like error sets:
//
// const Fruit = enum{ apple, pear, orange };
//
// const my_fruit = Fruit.apple;
//
// Let's use an enum in place of the numbers we were using in the
// previous version!
//
const std = @import("std");
// Please complete the enum!
const Ops = enum { inc, pow, dec };
pub fn main() void {
const operations = [_]Ops{
Ops.inc,
Ops.inc,
Ops.inc,
Ops.pow,
Ops.dec,
Ops.dec,
};
var current_value: u32 = 0;
for (operations) |op| {
switch (op) {
Ops.inc => {
current_value += 1;
},
Ops.dec => {
current_value -= 1;
},
Ops.pow => {
current_value *= current_value;
},
// No "else" needed! Why is that?
}
std.debug.print("{} ", .{current_value});
}
std.debug.print("\n", .{});
}
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