1const std = @import("std");
 2
 3// Although this function looks imperative, note that its job is to
 4// declaratively construct a build graph that will be executed by an external
 5// runner.
 6pub fn build(b: *std.Build) void {
 7    // Standard target options allows the person running `zig build` to choose
 8    // what target to build for. Here we do not override the defaults, which
 9    // means any target is allowed, and the default is native. Other options
10    // for restricting supported target set are available.
11    const target = b.standardTargetOptions(.{});
12
13    // Standard optimization options allow the person running `zig build` to select
14    // between Debug, ReleaseSafe, ReleaseFast, and ReleaseSmall. Here we do not
15    // set a preferred release mode, allowing the user to decide how to optimize.
16    const optimize = b.standardOptimizeOption(.{});
17
18    const exe = b.addExecutable(.{
19        .name = "hello-world",
20        // In this case the main source file is merely a path, however, in more
21        // complicated build scripts, this could be a generated file.
22        .root_source_file = .{ .path = "src/main.zig" },
23        .target = target,
24        .optimize = optimize,
25    });
26
27    // This declares intent for the executable to be installed into the
28    // standard location when the user invokes the "install" step (the default
29    // step when running `zig build`).
30    b.installArtifact(exe);
31
32    // This *creates* a Run step in the build graph, to be executed when another
33    // step is evaluated that depends on it. The next line below will establish
34    // such a dependency.
35    const run_cmd = b.addRunArtifact(exe);
36
37    // By making the run step depend on the install step, it will be run from the
38    // installation directory rather than directly from within the cache directory.
39    // This is not necessary, however, if the application depends on other installed
40    // files, this ensures they will be present and in the expected location.
41    run_cmd.step.dependOn(b.getInstallStep());
42
43    // This allows the user to pass arguments to the application in the build
44    // command itself, like this: `zig build run -- arg1 arg2 etc`
45    if (b.args) |args| {
46        run_cmd.addArgs(args);
47    }
48
49    // This creates a build step. It will be visible in the `zig build --help` menu,
50    // and can be selected like this: `zig build run`
51    // This will evaluate the `run` step rather than the default, which is "install".
52    const run_step = b.step("run", "Run the app");
53    run_step.dependOn(&run_cmd.step);
54
55    // Creates a step for unit testing. This only builds the test executable
56    // but does not run it.
57    const unit_tests = b.addTest(.{
58        .root_source_file = .{ .path = "src/main.zig" },
59        .target = target,
60        .optimize = optimize,
61    });
62
63    const run_unit_tests = b.addRunArtifact(unit_tests);
64
65    // Similar to creating the run step earlier, this exposes a `test` step to
66    // the `zig build --help` menu, providing a way for the user to request
67    // running the unit tests.
68    const test_step = b.step("test", "Run unit tests");
69    test_step.dependOn(&run_unit_tests.step);
70}