···
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const std = @import("std");
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// Although this function looks imperative, it does not perform the build
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// directly and instead it mutates the build graph (`b`) that will be then
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// executed by an external runner. The functions in `std.Build` implement a DSL
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// for defining build steps and express dependencies between them, allowing the
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// build runner to parallelize the build automatically (and the cache system to
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// know when a step doesn't need to be re-run).
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pub fn build(b: *std.Build) void {
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// Standard target options allow the person running `zig build` to choose
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// what target to build for. Here we do not override the defaults, which
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// means any target is allowed, and the default is native. Other options
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// for restricting supported target set are available.
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const target = b.standardTargetOptions(.{});
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// Standard optimization options allow the person running `zig build` to select
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// between Debug, ReleaseSafe, ReleaseFast, and ReleaseSmall. Here we do not
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// set a preferred release mode, allowing the user to decide how to optimize.
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const optimize = b.standardOptimizeOption(.{});
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// It's also possible to define more custom flags to toggle optional features
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// of this build script using `b.option()`. All defined flags (including
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// target and optimize options) will be listed when running `zig build --help`
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// in this directory.
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// This creates a module, which represents a collection of source files alongside
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// some compilation options, such as optimization mode and linked system libraries.
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// Zig modules are the preferred way of making Zig code available to consumers.
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// addModule defines a module that we intend to make available for importing
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// to our consumers. We must give it a name because a Zig package can expose
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// multiple modules and consumers will need to be able to specify which
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// module they want to access.
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// Here we define an executable. An executable needs to have a root module
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// which needs to expose a `main` function. While we could add a main function
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// to the module defined above, it's sometimes preferable to split business
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// logic and the CLI into two separate modules.
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// If your goal is to create a Zig library for others to use, consider if
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// it might benefit from also exposing a CLI tool. A parser library for a
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// data serialization format could also bundle a CLI syntax checker, for example.
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// If instead your goal is to create an executable, consider if users might
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// be interested in also being able to embed the core functionality of your
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// program in their own executable in order to avoid the overhead involved in
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// subprocessing your CLI tool.
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// If neither case applies to you, feel free to delete the declaration you
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// don't need and to put everything under a single module.
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const exe = b.addExecutable(.{
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.root_module = b.createModule(.{
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// b.createModule defines a new module just like b.addModule but,
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// unlike b.addModule, it does not expose the module to consumers of
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// this package, which is why in this case we don't have to give it a name.
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.root_source_file = b.path("src/main.zig"),
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// Target and optimization levels must be explicitly wired in when
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// defining an executable or library (in the root module), and you
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// can also hardcode a specific target for an executable or library
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// definition if desireable (e.g. firmware for embedded devices).
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.optimize = optimize,
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// List of modules available for import in source files part of the
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// This declares intent for the executable to be installed into the
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// install prefix when running `zig build` (i.e. when executing the default
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// step). By default the install prefix is `zig-out/` but can be overridden
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// by passing `--prefix` or `-p`.
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b.installArtifact(exe);
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// This creates a top level step. Top level steps have a name and can be
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// invoked by name when running `zig build` (e.g. `zig build run`).
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// This will evaluate the `run` step rather than the default step.
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// For a top level step to actually do something, it must depend on other
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// steps (e.g. a Run step, as we will see in a moment).
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const run_step = b.step("run", "Run the app");
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// This creates a RunArtifact step in the build graph. A RunArtifact step
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// invokes an executable compiled by Zig. Steps will only be executed by the
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// runner if invoked directly by the user (in the case of top level steps)
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// or if another step depends on it, so it's up to you to define when and
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// how this Run step will be executed. In our case we want to run it when
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// the user runs `zig build run`, so we create a dependency link.
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const run_cmd = b.addRunArtifact(exe);
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run_step.dependOn(&run_cmd.step);
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// By making the run step depend on the default step, it will be run from the
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// installation directory rather than directly from within the cache directory.
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run_cmd.step.dependOn(b.getInstallStep());
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// This allows the user to pass arguments to the application in the build
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// command itself, like this: `zig build run -- arg1 arg2 etc`
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if (b.args) |args| {
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run_cmd.addArgs(args);
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// Creates an executable that will run `test` blocks from the executable's
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// root module. Note that test executables only test one module at a time,
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// hence why we have to create two separate ones.
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const exe_tests = b.addTest(.{
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.root_module = exe.root_module,
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// A run step that will run the second test executable.
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const run_exe_tests = b.addRunArtifact(exe_tests);
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// A top level step for running all tests. dependOn can be called multiple
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// times and since the two run steps do not depend on one another, this will
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// make the two of them run in parallel.
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const test_step = b.step("test", "Run tests");
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test_step.dependOn(&run_exe_tests.step);
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// Just like flags, top level steps are also listed in the `--help` menu.
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// The Zig build system is entirely implemented in userland, which means
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// that it cannot hook into private compiler APIs. All compilation work
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// orchestrated by the build system will result in other Zig compiler
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// subcommands being invoked with the right flags defined. You can observe
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// these invocations when one fails (or you pass a flag to increase
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// verbosity) to validate assumptions and diagnose problems.
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// Lastly, the Zig build system is relatively simple and self-contained,
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// and reading its source code will allow you to master it.
aylac.top