mirror of
https://codeberg.org/ziglings/exercises.git
synced 2025-11-04 04:35:38 +00:00
79 lines
2.5 KiB
Zig
79 lines
2.5 KiB
Zig
//
|
|
// Now that we've seen how methods work, let's see if we can help
|
|
// our elephants out a bit more with some Elephant methods.
|
|
//
|
|
const std = @import("std");
|
|
|
|
const Elephant = struct {
|
|
letter: u8,
|
|
tail: ?*Elephant = null,
|
|
visited: bool = false,
|
|
|
|
// New Elephant methods!
|
|
pub fn getTail(self: *Elephant) *Elephant {
|
|
return self.tail.?; // Remember, this means "orelse unreachable"
|
|
}
|
|
|
|
pub fn hasTail(self: *Elephant) bool {
|
|
return (self.tail != null);
|
|
}
|
|
|
|
pub fn visit(self: *Elephant) void {
|
|
self.visited = true;
|
|
}
|
|
|
|
pub fn print(self: *Elephant) void {
|
|
// Prints elephant letter and [v]isited
|
|
const v: u8 = if (self.visited) 'v' else ' ';
|
|
std.debug.print("{u}{u} ", .{ self.letter, v });
|
|
}
|
|
};
|
|
|
|
pub fn main() void {
|
|
var elephantA = Elephant{ .letter = 'A' };
|
|
var elephantB = Elephant{ .letter = 'B' };
|
|
var elephantC = Elephant{ .letter = 'C' };
|
|
|
|
// This links the elephants so that each tail "points" to the next.
|
|
elephantA.tail = &elephantB;
|
|
elephantB.tail = &elephantC;
|
|
|
|
visitElephants(&elephantA);
|
|
|
|
std.debug.print("\n", .{});
|
|
}
|
|
|
|
// This function visits all elephants once, starting with the
|
|
// first elephant and following the tails to the next elephant.
|
|
fn visitElephants(first_elephant: *Elephant) void {
|
|
var e = first_elephant;
|
|
|
|
while (true) {
|
|
e.print();
|
|
e.visit();
|
|
|
|
// This gets the next elephant or stops:
|
|
// which method do we want here?
|
|
e = if (e.hasTail()) e.??? else break;
|
|
}
|
|
}
|
|
|
|
// Zig's enums can also have methods! This comment originally asked
|
|
// if anyone could find instances of enum methods in the wild. The
|
|
// first five pull requests were accepted and here they are:
|
|
//
|
|
// 1) drforester - I found one in the Zig source:
|
|
// https://github.com/ziglang/zig/blob/041212a41cfaf029dc3eb9740467b721c76f406c/src/Compilation.zig#L2495
|
|
//
|
|
// 2) bbuccianti - I found one!
|
|
// https://github.com/ziglang/zig/blob/6787f163eb6db2b8b89c2ea6cb51d63606487e12/lib/std/debug.zig#L477
|
|
//
|
|
// 3) GoldsteinE - Found many, here's one
|
|
// https://github.com/ziglang/zig/blob/ce14bc7176f9e441064ffdde2d85e35fd78977f2/lib/std/target.zig#L65
|
|
//
|
|
// 4) SpencerCDixon - Love this language so far :-)
|
|
// https://github.com/ziglang/zig/blob/a502c160cd51ce3de80b3be945245b7a91967a85/src/zir.zig#L530
|
|
//
|
|
// 5) tomkun - here's another enum method
|
|
// https://github.com/ziglang/zig/blob/4ca1f4ec2e3ae1a08295bc6ed03c235cb7700ab9/src/codegen/aarch64.zig#L24
|