Advanced Build Patterns

As your Chemical projects grow, you can use advanced patterns in build.lab to manage complexity, integrate C/C++ code, and automate post-build actions.

Multi-Module Orchestration

You can import other build.lab files to organize your build logic. This is commonly used in monorepos or when building complex test suites.

// build.lab

import lab

import "./libs/my_lib/build.lab" as myLib



func build(ctx : *mut AppBuildContext) {

    var exe = ctx.build_exe("my_app")

    

    // Add module defined in another build.lab

    ctx.add_module(exe, myLib.build(ctx, exe))

}

Build Hooks

The on_finished hook allows you to run code after a build job completes. This is useful for launching the executable immediately or performing cleanup.

var jc = JobContext { ctx: ctx, job: exe }



ctx.on_finished((data : *void) => {

    const j = data as *mut JobContext

    if (j.job.getStatus() == LabJobStatus.Success) {

        printf("Build succeeded! Launching...\n")

        j.ctx.launch_executable(j.job.getAbsPath(), true)

    }

}, &jc)

C/C++ Interoperability

The lab engine makes it easy to combine Chemical code with existing C or C++ modules.

Including C Files

const c_mod = ctx.c_file_module(

    std::string_view(""), 

    std::string_view("my_c_logic"), 

    std::string_view("src/logic.c"), 

    []

)

ctx.add_module(exe_job, c_mod)

Translating C to Chemical

You can even translate C files to Chemical at build time to facilitate easier integration.

const input_c = "src/legacy.c"

const output_ch = ctx.build_mod_file_path(exe_name, "", "translated", "legacy.ch")

ctx.translate_file_to_chemical(input_c, output_ch)

Custom CLI Arguments

You can pass custom flags to your build.lab script from the command line using the --arg- prefix.

chemical build.lab --arg-my_custom_flag=true

if (ctx.has_arg("my_custom_flag")) {

    printf("Custom flag value: %s\n", ctx.get_arg("my_custom_flag").data())

}

Environment Flags

Use ctx.define to set compile-time definitions (equivalent to #define in C or def.OS in Chemical).

ctx.define(exe_job, "EXPERIMENTAL_FEATURE")