如何在build.zig中以惯用方式调用C代码生成器？

我正在推进一个结合gSOAP与Zig的项目：从纯C代码起步，逐步用Zig进行替换。项目核心是使用gSOAP的WSDL转C代码生成器，原本驱动该流程的Makefile代码如下：

gen: addition.wsdl
    mkdir -p $@
    wsdl2h ./$< -c  -o $@/addition.h
    soapcpp2 -c -r -dgen/ $@/addition.h

我已用Zig实现了等效逻辑，但代码冗长且需手动控制命令执行顺序：

// Generate gSOAP artefacts
{
    const wsdl_input = "addition.wsdl";
    const gen_step = b.step("gen", "Generate gSOAP artefacts");

    const gen_run0 = b.addSystemCommand(&.{ "mkdir", "-p", generated_sources });
    const gen_run1 = b.addSystemCommand(&.{ "wsdl2h", wsdl_input, "-c", "-o", generated_sources ++ "/addition.h" });
    const gen_run2 = b.addSystemCommand(&.{ "soapcpp2", "-c", "-r", "-d" ++ generated_sources, generated_sources ++ "/addition.h" });

    // Ensure the commands run in order .. not a given otherwise
    gen_run1.step.dependOn(&gen_run0.step);
    gen_run2.step.dependOn(&gen_run1.step);
    gen_step.dependOn(&gen_run2.step);

    b.default_step.dependOn(gen_step);
}

想了解是否存在更简便、更符合Zig惯用风格的方式来创建子目录并按顺序运行这两个代码生成器？

1. 简化依赖链与字符串处理 #

Zig Build System支持更简洁的依赖绑定，同时用b.fmt替代手动字符串拼接（更符合Zig惯用写法，避免拼接错误）：

// Generate gSOAP artefacts
{
    const wsdl_input = "addition.wsdl";
    const gen_step = b.step("gen", "Generate gSOAP artefacts");

    // 创建输出目录
    const mkdir_step = b.addSystemCommand(&.{ "mkdir", "-p", generated_sources });
    // 生成头文件，依赖目录创建完成
    const header_path = b.fmt("{s}/addition.h", .{generated_sources});
    const wsdl2h_step = b.addSystemCommand(&.{ "wsdl2h", wsdl_input, "-c", "-o", header_path });
    wsdl2h_step.step.dependOn(&mkdir_step.step);
    // 生成gSOAP代码，依赖头文件生成完成
    const soapcpp2_step = b.addSystemCommand(&.{ "soapcpp2", "-c", "-r", "-d", generated_sources, header_path });
    soapcpp2_step.step.dependOn(&wsdl2h_step.step);

    // 绑定到gen目标与默认步骤
    gen_step.dependOn(&soapcpp2_step.step);
    b.default_step.dependOn(gen_step);
}

2. 用Zig原生API替代外部mkdir命令 #

Zig 0.11+版本提供了addMakeDirStep，可以直接通过Build System创建目录，无需调用外部mkdir命令，更贴合Zig生态：

// Generate gSOAP artefacts
{
    const wsdl_input = "addition.wsdl";
    const gen_step = b.step("gen", "Generate gSOAP artefacts");

    // 用Zig原生API创建目录（自动处理父目录）
    const make_dir_step = b.addMakeDirStep(generated_sources);
    
    // 生成头文件
    const header_path = b.fmt("{s}/addition.h", .{generated_sources});
    const wsdl2h_step = b.addSystemCommand(&.{ "wsdl2h", wsdl_input, "-c", "-o", header_path });
    wsdl2h_step.step.dependOn(&make_dir_step.step);

    // 生成gSOAP代码
    const soapcpp2_step = b.addSystemCommand(&.{ "soapcpp2", "-c", "-r", "-d", generated_sources, header_path });
    soapcpp2_step.step.dependOn(&wsdl2h_step.step);

    gen_step.dependOn(&soapcpp2_step.step);
    b.default_step.dependOn(gen_step);
}

如果需要先清理旧目录，可以在创建目录前添加b.addRemoveDirStep(generated_sources)，并让make_dir_step依赖它。

3. 封装成可复用函数 #

如果后续需要处理多个WSDL文件，把生成逻辑封装成函数能大幅提升代码复用性：

const std = @import("std");

fn generateGsoapArtifacts(b: *std.Build, wsdl_path: []const u8, output_dir: []const u8) *std.Build.Step {
    const gen_step = b.step("gen", "Generate gSOAP artefacts");

    // 创建输出目录
    const make_dir_step = b.addMakeDirStep(output_dir);

    // 生成头文件
    const header_path = b.fmt("{s}/addition.h", .{output_dir});
    const wsdl2h_step = b.addSystemCommand(&.{ "wsdl2h", wsdl_path, "-c", "-o", header_path });
    wsdl2h_step.step.dependOn(&make_dir_step.step);

    // 生成gSOAP代码
    const soapcpp2_step = b.addSystemCommand(&.{ "soapcpp2", "-c", "-r", "-d", output_dir, header_path });
    soapcpp2_step.step.dependOn(&wsdl2h_step.step);

    gen_step.dependOn(&soapcpp2_step.step);
    return gen_step;
}

// 在build函数中调用
pub fn build(b: *std.Build) void {
    const generated_sources = "gen";
    const gen_step = generateGsoapArtifacts(b, "addition.wsdl", generated_sources);
    b.default_step.dependOn(gen_step);
}

内容的提问来源于stack exchange，提问作者Martin Cowie