§ Learn Zig in Y minutes

const std = @import("std");

// global variables.
const x = 1234;

//! Top level comments are setup using //!
//! This module provides functions for retrieving the current date and
//! time with varying degrees of precision and accuracy. It does not
//! depend on libc, but will use functions from it if available.
pub fn main() !void {
    const stdout = std.io.getStdOut().writer();
    try stdout.print("Hello, {}!\n", .{"world"});
    // Comments in Zig start with "//" and end at the next LF byte (end of line).
    // The below line is a comment, and won't be executed.

    // integers
    const one_plus_one: i32 = 1 + 1;
    print("1 + 1 = {}\n", .{one_plus_one});

    // floats
    const seven_div_three: f32 = 7.0 / 3.0;
    print("7.0 / 3.0 = {}\n", .{seven_div_three});

    // boolean
    print("{}\n{}\n{}\n", .{
        true and false,
        true or false,
        !true,
    });

    // optional
    var optional_value: ?[]const u8 = null;
    assert(optional_value == null);

    print("\noptional 1\ntype: {}\nvalue: {}\n", .{
        @typeName(@TypeOf(optional_value)),
        optional_value,
    });

    optional_value = "hi";
    assert(optional_value != null);

    print("\noptional 2\ntype: {}\nvalue: {}\n", .{
        @typeName(@TypeOf(optional_value)),
        optional_value,
    });

    // error union
    var number_or_error: anyerror!i32 = error.ArgNotFound;

    print("\nerror union 1\ntype: {}\nvalue: {}\n", .{
        @typeName(@TypeOf(number_or_error)),
        number_or_error,
    });

    number_or_error = 1234;

    print("\nerror union 2\ntype: {}\nvalue: {}\n", .{
        @typeName(@TypeOf(number_or_error)),
        number_or_error,
    });

    // It works at global scope as well as inside functions.
    const y = 5678;


}



// Top-level declarations are order-independent:
pub fn g() { f(); }
pub fn f() {}

test "string literals" {
    const bytes = "hello";
    assert(@TypeOf(bytes) == *const [5:0]u8);
    assert(bytes.len == 5);
    assert(bytes[1] == 'e');
    assert(bytes[5] == 0);
    assert('e' == '\x65');
    assert('\u{1f4a9}' == 128169);
    assert('💯' == 128175);
    assert(mem.eql(u8, "hello", "h\x65llo"));
}