fix code format

- Workspace support (`[workspace]` with deps ordering)
- `clean --all` for workspace members
Changed:
- Project root discovery for `build/run/clean` (searches parent dirs)
- Workspace paths are excluded from root source scan
- Build output now uses a Cargo-style `Compiling <name> v<version>` line
- Build time now reports total time for the whole build stage (workspace included)
- Cache hits are silent (no compile line when nothing is rebuilt)
- Safer build cache: fingerprints include headers and resolved library files

AGENT.md

@@ -0,0 +1,126 @@
+# AGENT.md
+
+## Project Overview
+
+**DCR (Dexoron Cargo Realization)** — CLI-утилита для управления C/C++/ASM проектами в стиле Cargo.
+
+- **Язык реализации**: Rust (edition 2024)
+- **Лицензия**: MIT
+- **Репозиторий**: [github.com/dexoron/dcr](https://github.com/dexoron/dcr)
+
+## Architecture
+
+### Source Tree (`src/`)
+
+```
+src/
+├── main.rs          # Точка входа, маршрутизация CLI-команд
+├── config.rs        # Глобальные константы: профили сборки, шаблон main.c
+├── cli/             # Реализация CLI-команд
+│   ├── new.rs       # dcr new <name>
+│   ├── init.rs      # dcr init
+│   ├── build.rs     # dcr build [--debug|--release]
+│   ├── run.rs       # dcr run [--debug|--release]
+│   ├── clean.rs     # dcr clean [--all]
+│   ├── help.rs      # dcr --help
+│   └── flag_update.rs  # dcr --update (self-update через GitHub Releases)
+├── core/            # Бизнес-логика
+│   ├── config.rs    # Парсинг/валидация/форматирование dcr.toml (struct Config)
+│   ├── deps.rs      # Разрешение path-зависимостей, генерация dcr.lock
+│   ├── runner.rs    # Запуск скомпилированного бинарника
+│   ├── workspace.rs # Поддержка [workspace] и упорядочивание сборки
+│   └── builder/     # Бэкенды компиляторов/ассемблеров
+│       ├── mod.rs   # Общий интерфейс сборки
+│       ├── gcc.rs   # GCC backend
+│       ├── clang.rs # Clang backend
+│       ├── msvc.rs  # MSVC backend
+│       ├── nasm.rs  # NASM backend (ASM)
+│       └── gas.rs   # GAS backend (ASM)
+├── platform/        # Платформенно-зависимая логика
+│   ├── mod.rs       # Общий интерфейс платформ
+│   ├── linux.rs
+│   ├── macos.rs
+│   └── windows.rs
+└── utils/           # Вспомогательные утилиты
+    ├── fs.rs        # Работа с файловой системой
+    ├── log.rs       # Логирование (error, warn)
+    └── text.rs      # Форматирование текста / цвета
+```
+
+### Key Concepts
+
+- **`dcr.toml`** — конфигурационный файл проекта (аналог `Cargo.toml`). Секции: `[package]`, `[build]`, `[toolchain]`, `[dependencies]`, `[workspace]`.
+- **Профили сборки**: `debug` (по умолчанию) и `release`. Встроенные флаги зависят от компилятора. Пользовательские флаги через `build.cflags` / `build.ldflags`.
+- **Инкрементальная сборка**: объектные файлы кешируются по mtime. Отслеживание заголовков пока не реализовано (см. `TODO.md`).
+- **Workspace**: корневой `dcr.toml` с секцией `[workspace]` описывает member-проекты и их зависимости; сборка происходит в топологическом порядке.
+- **Path dependencies**: зависимости по путям автоматически добавляют include/lib-пути; генерируется `dcr.lock`.
+- **Build kinds**: `bin` (бинарник), `staticlib` (`.a`), `sharedlib` (`.so`/`.dylib`/`.dll`).
+
+## Supported Platforms
+
+| Platform | Target triple |
+|---|---|
+| Linux | `x86_64-unknown-linux-gnu` |
+| macOS Intel | `x86_64-apple-darwin` |
+| macOS ARM | `aarch64-apple-darwin` |
+| Windows | `x86_64-pc-windows-msvc` |
+
+## Dependencies (Cargo)
+
+| Crate | Purpose |
+|---|---|
+| `reqwest` | HTTP-запросы для `--update` (blocking, rustls-tls) |
+| `serde` | Сериализация/десериализация |
+| `toml` | Парсинг `dcr.toml` |
+| `sha2` | Хеширование при обновлении |
+| `self-replace` | Замена бинарника при `--update` |
+
+## Development
+
+### Build & Run
+
+```bash
+cargo build             # debug build
+cargo build --release   # release build
+cargo run -- new hello  # создать проект "hello"
+```
+
+### Code Quality
+
+```bash
+cargo fmt --all
+cargo clippy --all-targets --all-features -- -D warnings
+cargo check
+cargo test
+```
+
+### CI/CD
+
+- **CI**: `.github/workflows/ci.yml` — проверки при PR/push
+- **Release**: `.github/workflows/release.yml` — сборка бинарников при пуше тега `v*`
+
+### Tests
+
+- Интеграционные CLI-тесты: `tests/cli_basic.rs`
+
+## Code Conventions
+
+- Rust stable edition 2024
+- Форматирование: `cargo fmt`
+- Линтинг: `cargo clippy` без warnings
+- Функции — маленькие и сфокусированные
+- Имена — понятные и описательные
+- Пользовательские сообщения CLI — на английском языке
+- Вывод ошибок/предупреждений через `utils::log::{error, warn}`
+
+## TODO
+
+- В файле `TODO.md`
+
+## Useful Links
+
+- Документация проекта: `docs/`
+- Changelog: `CHANGELOG.md`
+- Contributing: `CONTRIBUTING.md`
+- FAQ: `FAQ.md`
+- Установка: `install.sh` (Linux/macOS), `install.ps1` (Windows)

CHANGELOG.md

@@ -1,5 +1,32 @@
 # Changelog
 
+## [0.2.9] - 2026-03-14
+Added:
+- Header dependency tracking for fine-grained incremental builds (rebuilds when `#include` files change)
+- Complete internal rewrite of the builder module: merged duplicate compilation backends
+
+Changed:
+- `cflags` and `default_flags` no longer incorrectly leak to the linker stage in GCC/Clang
+- Reduced builder codebase size by over 20% while increasing reliability
+- Greatly expanded test suite with 34 new tests covering configuration, CLI errors, and path operations
+
+## [0.2.8] - 2026-03-06
+Added:
+- Workspace support (`[workspace]` with deps ordering)
+- `clean --all` for workspace members
+Changed:
+- Project root discovery for `build/run/clean` (searches parent dirs)
+- Workspace paths are excluded from root source scan
+- Build output now uses a Cargo-style `Compiling <name> v<version>` line
+- Build time now reports total time for the whole build stage (workspace included)
+- Cache hits are silent (no compile line when nothing is rebuilt)
+- Safer build cache: fingerprints include headers and resolved library files
+
+## [0.2.7] - 2026-03-03
+Added:
+- Toolchain overrides via `[toolchain]` and env (`DCR_*`)
+- ASM `.S` preprocessing via GCC/Clang (`-x assembler-with-cpp`)
+
 ## [0.2.6] - 2026-03-01
 Added:
 - `sharedlib` build kind (shared library output)

Cargo.lock

@@ -90,7 +90,7 @@ dependencies = [
 
 [[package]]
 name = "dcr"
-version = "0.2.6"
+version = "0.2.9"
 dependencies = [
  "reqwest",
  "self-replace",

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "dcr"
-version = "0.2.6"
+version = "0.2.9"
 edition = "2024"
 build = "build.rs"
 

README.md

@@ -113,6 +113,7 @@ Run manually:
 
 ### `dcr clean`
 Removes the `target` directory in the project root.
+Use `dcr clean --all` in a workspace root to clean all member projects.
 
 ## Build Profiles
 Two profiles are supported:
@@ -146,9 +147,26 @@ compiler = "clang"
 cflags = ["-Wall", "-Wextra"]
 ldflags = ["-lm"]
 
+[toolchain]
+# Optional tool overrides:
+# cc = "clang"
+# cxx = "clang++"
+# as = "as"
+# ar = "ar"
+# ld = "ld"
+
 [dependencies]
 ```
 
+Workspace example:
+
+```toml
+[workspace]
+kernel = { path = "src/kernel", deps = ["core", "userspace"] }
+core = { path = "src/core", deps = ["userspace"] }
+userspace = { path = "src/userspace" }
+```
+
 Path dependencies are supported. DCR will resolve them on build and generate `dcr.lock`.
 
 Incremental build note: object files are rebuilt when source `.c/.cpp` files change. Header dependency tracking is not implemented yet.

TODO.md

@@ -1,9 +1,9 @@
 # TODO
 
-- Add header dependency tracking for incremental builds (GCC/Clang: -MMD, MSVC: /showIncludes)
 - Add external package managers (Conan, vcpkg)
-- Multi-target
-- ASM support
 - Linker script + direct linker control
 - Custom targets/steps
-- Tool overrides and env vars
+- Cross-compilation and freestanding targets (-nostdinc, -nostdlib, custom target triple like i686-elf)
+- Mixed C + ASM in one project (compile .c and .s/.S sources together)
+- Per-member include directories in workspace (e.g. include paths for subprojects)
+- Build-time code generation (auto-generated headers, pre-build scripts)

docs/README.md

@@ -24,6 +24,7 @@ Current DCR focuses on a simple, predictable workflow:
   - `sharedlib`
 - Optional custom output directory via `build.target`.
 - Optional `build.platform` to pass architecture hints (`-march` / `/arch`).
+- Workspace builds via `[workspace]` with per-project `dcr.toml`.
 - Path dependencies with include/lib resolution and `dcr.lock` generation.
 
 ## Important behavior notes

docs/commands/dcr-build.md

@@ -43,3 +43,4 @@ dcr build --release
 - Unknown profile flags return an error.
 - Incremental rebuild is based on source/object mtime comparison.
 - For `language = "asm"` with `compiler = "as"`/`"gas"`, use `.s` files (no preprocessing). For `.S`, use `gcc` or `clang`.
+- In workspace root, `dcr build` builds all members in dependency order.

docs/commands/dcr-clean.md

@@ -8,16 +8,18 @@ Removes build artifacts in `target/`.
 dcr clean
 dcr clean --debug
 dcr clean --release
+dcr clean --all
+dcr clean --release --all
 ```
 
 ## Behavior
 
 - Without arguments: removes entire `target/`.
 - With profile: removes only `target/<profile>/`.
+- With `--all`: also cleans all workspace members.
 
 ## Validation
 
 - `dcr.toml` must exist.
-- More than one argument is treated as error.
+- Unknown flags are treated as error.
-- Unknown profile is treated as error.
 - If `target` or selected profile directory does not exist, command prints a warning.

docs/configuration/build-section.md

@@ -26,6 +26,17 @@ kind = "bin"
 - `cflags` (string array, optional): extra compile flags.
 - `ldflags` (string array, optional): extra link flags.
 
+## Toolchain section
+
+```toml
+[toolchain]
+cc = "clang"
+cxx = "clang++"
+as = "as"
+ar = "ar"
+ld = "ld"
+```
+
 ## Behavior notes
 
 - Compiler backend is selected by compiler string (`gcc`, `clang`, `cl`, `clang-cl`).

docs/configuration/dcr.toml-overview.md

@@ -26,6 +26,9 @@ kind = "bin"
 - `[build]`
 - `[dependencies]`
 
+Workspace-only root:
+- `[workspace]` may be used instead of `[package]`/`[build]` for a workspace root.
+
 ## Required keys
 
 - `package.name`
@@ -43,3 +46,5 @@ kind = "bin"
 - `build.cflags`
 - `build.ldflags`
 - dependency fields (`include`, `lib`, `libs`, `system`)
+- `[toolchain]` overrides (`cc`, `cxx`, `as`, `ar`, `ld`)
+- `[workspace]` members

docs/dependencies-and-build/compilers-and-linking.md

@@ -39,6 +39,18 @@ If `build.platform` is set, DCR passes it as an architecture hint:
 - GCC/Clang: `-march=<platform>`
 - MSVC: maps to `/arch:*` for known values (`x86`, `i386`, `i486`, `i586`, `i686`, `sse2`, `avx`, `avx2`)
 
+## Toolchain overrides
+
+If `[toolchain]` is set, DCR uses its values to override compiler/linker tools:
+
+- `cc`, `cxx`, `as` override compilers for C/C++/ASM
+- `ar` overrides the archiver (used for `staticlib`)
+- `ld` overrides the linker (used by GCC/Clang/NASM/GAS backends)
+
+Environment overrides (highest priority):
+- `DCR_COMPILER` (all languages)
+- `DCR_CC`, `DCR_CXX`, `DCR_AS`, `DCR_AR`, `DCR_LD`
+
 ## Linking
 
 For `kind = "bin"`:

docs/getting-started/build-and-run.md

@@ -37,6 +37,8 @@ Profile-only cleanup:
 ```sh
 dcr clean --debug
 dcr clean --release
+dcr clean --all
+dcr clean --release --all
 ```
 
 ## Notes
@@ -44,3 +46,4 @@ dcr clean --release
 - `run` is unavailable for `build.kind = "staticlib"` and `build.kind = "sharedlib"`.
 - Build profile flag is parsed from the first command argument.
 - Unknown profile flags produce an error.
+- In workspace root, `clean --all` cleans all member projects.

docs/reference-and-help/cli-reference.md

@@ -7,7 +7,7 @@ dcr new <name>
 dcr init
 dcr build [--debug|--release]
 dcr run [--debug|--release]
-dcr clean [--debug|--release]
+dcr clean [--debug|--release] [--all]
 dcr --help
 dcr --version
 dcr --update
@@ -18,7 +18,7 @@ dcr --update
 - Most commands parse profile from the first argument.
 - `new` requires exactly one argument.
 - `init` and `--update` do not accept extra arguments.
-- `clean` accepts at most one argument.
+- `clean` accepts `--debug|--release` and optional `--all`.
 
 ## Exit behavior overview
 

docs/reference-and-help/config-reference.md

@@ -17,6 +17,16 @@ platform = "string"            # optional
 cflags = ["string", "..."]     # optional
 ldflags = ["string", "..."]    # optional
 
+[toolchain]
+cc = "string"   # optional
+cxx = "string"  # optional
+as = "string"   # optional
+ar = "string"   # optional
+ld = "string"   # optional
+
+[workspace]
+name = { path = "string", deps = ["string", "..."] }
+
 [dependencies]
 name = {
   path = "string",              # required for each dependency

src/cli/build.rs

@@ -1,24 +1,32 @@
 use crate::config::{PROFILE, flags};
-use crate::core::builder::{BuildContext, build as build_project};
+use crate::core::builder::{BuildContext, build as build_project, collect_sources};
 use crate::core::config::Config;
 use crate::core::deps::resolve_deps;
-use crate::utils::fs::check_dir;
+use crate::core::workspace::parse_workspace;
+use crate::utils::fs::{check_dir, find_project_root};
 use crate::utils::log::{error, warn};
 use crate::utils::text::{BOLD_GREEN, colored};
+use sha2::{Digest, Sha256};
 use std::fs;
+use std::path::Path;
 use std::time::Instant;
 
 pub fn build(args: &[String]) -> i32 {
-    let items = check_dir(None).unwrap_or_default();
+    let start_dir = match std::env::current_dir() {
-    if !items.contains(&"dcr.toml".to_string()) {
+        Ok(dir) => dir,
+        Err(_) => {
+            error("Failed to determine current directory");
+            return 1;
+        }
+    };
+    let root = match find_project_root(&start_dir) {
+        Ok(Some(dir)) => dir,
+        Ok(None) => {
             error("dcr.toml file not found");
             return 1;
         }
-
-    let config = match Config::open("./dcr.toml") {
-        Ok(cfg) => cfg,
         Err(_) => {
-            error("dcr.toml file not found");
+            error("Failed to find project root");
             return 1;
         }
     };
@@ -26,75 +34,8 @@ pub fn build(args: &[String]) -> i32 {
         Ok(profile) => profile,
         Err(code) => return code,
     };
-    let project_name = get_config_str(&config, "package.name");
+    match with_dir(&root, || build_from_root(&root, &active_profile)) {
-    let project_compiler = get_config_str(&config, "build.compiler");
+        Ok(()) => 0,
-    let build_language = get_config_str(&config, "build.language");
-    let build_standard = get_config_str(&config, "build.standard");
-    let build_target = get_config_str(&config, "build.target");
-    let build_kind = get_config_str(&config, "build.kind");
-    let build_platform = get_config_str(&config, "build.platform");
-    let build_cflags = match get_config_list(&config, "build.cflags") {
-        Ok(v) => v,
-        Err(msg) => {
-            error(&msg);
-            return 1;
-        }
-    };
-    let build_ldflags = match get_config_list(&config, "build.ldflags") {
-        Ok(v) => v,
-        Err(msg) => {
-            error(&msg);
-            return 1;
-        }
-    };
-
-    println!(
-        "    Building project `{}`\n    Profile: {}\n    Compiler: {}\n",
-        colored(&project_name, BOLD_GREEN),
-        colored(&active_profile, BOLD_GREEN),
-        colored(&project_compiler, BOLD_GREEN)
-    );
-
-    ensure_target_dirs(&items, &active_profile, normalize_target(&build_target));
-
-    let project_root = match std::env::current_dir() {
-        Ok(p) => p,
-        Err(_) => {
-            error("Failed to determine project root");
-            return 1;
-        }
-    };
-    let resolved = match resolve_deps(&config, &active_profile, &project_root) {
-        Ok(r) => r,
-        Err(msg) => {
-            error(&msg);
-            return 1;
-        }
-    };
-    let ctx = BuildContext {
-        profile: &active_profile,
-        project_name: &project_name,
-        compiler: &project_compiler,
-        language: &build_language,
-        standard: &build_standard,
-        target_dir: normalize_target(&build_target),
-        kind: normalize_kind(&build_kind),
-        platform: normalize_platform(&build_platform),
-        include_dirs: &resolved.include_dirs,
-        lib_dirs: &resolved.lib_dirs,
-        libs: &resolved.libs,
-        cflags: &build_cflags,
-        ldflags: &build_ldflags,
-    };
-    match run_build(&ctx) {
-        Ok(times) => {
-            println!(
-                "    {} Build completed successfully in {} seconds",
-                colored("✔", BOLD_GREEN),
-                colored(&times.to_string(), BOLD_GREEN)
-            );
-            0
-        }
         Err(msg) => {
             error(&msg);
             1
@@ -126,6 +67,16 @@ fn get_config_str(config: &Config, key: &str) -> String {
         .to_string()
 }
 
+fn get_config_opt(config: &Config, key: &str) -> Option<String> {
+    let value = config.get(key)?.as_str()?;
+    let trimmed = value.trim();
+    if trimmed.is_empty() {
+        None
+    } else {
+        Some(trimmed.to_string())
+    }
+}
+
 fn get_config_list(config: &Config, key: &str) -> Result<Vec<String>, String> {
     let value = match config.get(key) {
         Some(v) => v,
@@ -173,6 +124,136 @@ fn run_build(ctx: &BuildContext) -> Result<f64, String> {
     }
 }
 
+fn build_from_root(root: &Path, profile: &str) -> Result<(), String> {
+    let config = Config::open("./dcr.toml").map_err(|err| err.to_string())?;
+    let project_name = get_config_str(&config, "package.name");
+    let start_time = Instant::now();
+    println!(
+        "    Building project `{}`\n    Profile: {}",
+        colored(&project_name, BOLD_GREEN),
+        colored(profile, BOLD_GREEN)
+    );
+    if let Some(workspace) = parse_workspace(&config, root)? {
+        build_workspace(&workspace, profile)?;
+        let excludes: Vec<std::path::PathBuf> =
+            workspace.members.iter().map(|m| m.path.clone()).collect();
+        build_project_at(root, profile, &excludes)?;
+        let elapsed = ((start_time.elapsed().as_secs_f64() * 100.0).trunc()) / 100.0;
+        println!(
+            "    {} Build completed successfully in {} seconds",
+            colored("✔", BOLD_GREEN),
+            colored(&elapsed.to_string(), BOLD_GREEN)
+        );
+        return Ok(());
+    }
+    build_project_at(root, profile, &[])?;
+    let elapsed = ((start_time.elapsed().as_secs_f64() * 100.0).trunc()) / 100.0;
+    println!(
+        "    {} Build completed successfully in {} seconds",
+        colored("✔", BOLD_GREEN),
+        colored(&elapsed.to_string(), BOLD_GREEN)
+    );
+    Ok(())
+}
+
+fn build_workspace(
+    workspace: &crate::core::workspace::Workspace,
+    profile: &str,
+) -> Result<(), String> {
+    for member in &workspace.members {
+        build_project_at(&member.path, profile, &[])?;
+    }
+    Ok(())
+}
+
+fn build_project_at(
+    project_root: &Path,
+    profile: &str,
+    exclude_dirs: &[std::path::PathBuf],
+) -> Result<(), String> {
+    with_dir(project_root, || {
+        let items = check_dir(None).map_err(|_| "Failed to read project directory".to_string())?;
+        if !items.contains(&"dcr.toml".to_string()) {
+            return Err("dcr.toml file not found".to_string());
+        }
+        let config = Config::open("./dcr.toml").map_err(|err| err.to_string())?;
+        let project_name = get_config_str(&config, "package.name");
+        let project_version = get_config_str(&config, "package.version");
+        let project_compiler = get_config_str(&config, "build.compiler");
+        let build_language = get_config_str(&config, "build.language");
+        let build_standard = get_config_str(&config, "build.standard");
+        let build_target = get_config_str(&config, "build.target");
+        let build_kind = get_config_str(&config, "build.kind");
+        let build_platform = get_config_str(&config, "build.platform");
+        let tc_cc = get_config_opt(&config, "toolchain.cc");
+        let tc_cxx = get_config_opt(&config, "toolchain.cxx");
+        let tc_as = get_config_opt(&config, "toolchain.as");
+        let tc_ar = get_config_opt(&config, "toolchain.ar");
+        let tc_ld = get_config_opt(&config, "toolchain.ld");
+        let build_cflags = get_config_list(&config, "build.cflags")?;
+        let build_ldflags = get_config_list(&config, "build.ldflags")?;
+
+        let resolved_compiler = resolve_compiler(
+            &build_language,
+            &project_compiler,
+            tc_cc.as_deref(),
+            tc_cxx.as_deref(),
+            tc_as.as_deref(),
+        );
+        let resolved_linker = resolve_tool("DCR_LD", tc_ld.as_deref());
+        let resolved_archiver = resolve_tool("DCR_AR", tc_ar.as_deref());
+
+        ensure_target_dirs(&items, profile, normalize_target(&build_target));
+
+        let resolved = resolve_deps(&config, profile, project_root)?;
+        let ctx = BuildContext {
+            profile,
+            project_name: &project_name,
+            compiler: &resolved_compiler,
+            language: &build_language,
+            standard: &build_standard,
+            target_dir: normalize_target(&build_target),
+            kind: normalize_kind(&build_kind),
+            platform: normalize_platform(&build_platform),
+            linker: resolved_linker.as_deref(),
+            archiver: resolved_archiver.as_deref(),
+            exclude_dirs,
+            include_dirs: &resolved.include_dirs,
+            lib_dirs: &resolved.lib_dirs,
+            libs: &resolved.libs,
+            cflags: &build_cflags,
+            ldflags: &build_ldflags,
+        };
+        let sources = collect_sources(&ctx)?;
+        let headers = collect_header_files(&ctx, project_root)?;
+        let lib_files = collect_lib_files(&ctx);
+        let fingerprint = compute_build_fingerprint(&ctx, &sources, &headers, &lib_files)?;
+        if should_skip_build(&ctx, &fingerprint) {
+            return Ok(());
+        }
+        println!(
+            "   {} {} v{}",
+            colored("Compiling", BOLD_GREEN),
+            project_name,
+            project_version
+        );
+        run_build(&ctx)?;
+        write_build_fingerprint(&ctx, &fingerprint)?;
+        Ok(())
+    })
+}
+
+fn with_dir<F, T>(dir: &Path, f: F) -> Result<T, String>
+where
+    F: FnOnce() -> Result<T, String>,
+{
+    let prev = std::env::current_dir().map_err(|_| "Failed to get current dir".to_string())?;
+    std::env::set_current_dir(dir).map_err(|_| "Failed to change directory".to_string())?;
+    let result = f();
+    let _ = std::env::set_current_dir(prev);
+    result
+}
+
 fn normalize_target(target: &str) -> Option<&str> {
     let trimmed = target.trim();
     if trimmed.is_empty() {
@@ -195,3 +276,283 @@ fn normalize_platform(platform: &str) -> Option<&str> {
         Some(trimmed)
     }
 }
+
+fn resolve_compiler(
+    language: &str,
+    compiler: &str,
+    tc_cc: Option<&str>,
+    tc_cxx: Option<&str>,
+    tc_as: Option<&str>,
+) -> String {
+    let lang = language.to_lowercase();
+    env_override_compiler(&lang)
+        .or_else(|| toolchain_override_compiler(&lang, tc_cc, tc_cxx, tc_as))
+        .unwrap_or_else(|| compiler.to_string())
+}
+
+fn env_override_compiler(lang: &str) -> Option<String> {
+    if let Ok(value) = std::env::var("DCR_COMPILER") {
+        let trimmed = value.trim();
+        if !trimmed.is_empty() {
+            return Some(trimmed.to_string());
+        }
+    }
+    if lang == "asm" {
+        if let Ok(value) = std::env::var("DCR_AS") {
+            let trimmed = value.trim();
+            if !trimmed.is_empty() {
+                return Some(trimmed.to_string());
+            }
+        }
+        return None;
+    }
+    if (lang == "c++" || lang == "cpp" || lang == "cxx")
+        && let Ok(value) = std::env::var("DCR_CXX")
+    {
+        let trimmed = value.trim();
+        if !trimmed.is_empty() {
+            return Some(trimmed.to_string());
+        }
+    }
+    if let Ok(value) = std::env::var("DCR_CC") {
+        let trimmed = value.trim();
+        if !trimmed.is_empty() {
+            return Some(trimmed.to_string());
+        }
+    }
+    None
+}
+
+fn toolchain_override_compiler(
+    lang: &str,
+    tc_cc: Option<&str>,
+    tc_cxx: Option<&str>,
+    tc_as: Option<&str>,
+) -> Option<String> {
+    if lang == "asm" {
+        return tc_as.map(|v| v.to_string());
+    }
+    if (lang == "c++" || lang == "cpp" || lang == "cxx")
+        && let Some(v) = tc_cxx
+    {
+        return Some(v.to_string());
+    }
+    tc_cc.map(|v| v.to_string())
+}
+
+fn resolve_tool(env_key: &str, fallback: Option<&str>) -> Option<String> {
+    if let Ok(value) = std::env::var(env_key) {
+        let trimmed = value.trim();
+        if !trimmed.is_empty() {
+            return Some(trimmed.to_string());
+        }
+    }
+    fallback.map(|v| v.to_string())
+}
+
+fn compute_build_fingerprint(
+    ctx: &BuildContext,
+    sources: &[String],
+    headers: &[std::path::PathBuf],
+    lib_files: &[std::path::PathBuf],
+) -> Result<String, String> {
+    let mut hasher = Sha256::new();
+    hasher.update(ctx.profile.as_bytes());
+    hasher.update(ctx.project_name.as_bytes());
+    hasher.update(ctx.compiler.as_bytes());
+    hasher.update(ctx.language.as_bytes());
+    hasher.update(ctx.standard.as_bytes());
+    hasher.update(ctx.kind.as_bytes());
+    if let Some(v) = ctx.target_dir {
+        hasher.update(v.as_bytes());
+    }
+    if let Some(v) = ctx.platform {
+        hasher.update(v.as_bytes());
+    }
+    if let Some(v) = ctx.linker {
+        hasher.update(v.as_bytes());
+    }
+    if let Some(v) = ctx.archiver {
+        hasher.update(v.as_bytes());
+    }
+    for value in ctx.include_dirs {
+        hasher.update(value.as_bytes());
+    }
+    for value in ctx.lib_dirs {
+        hasher.update(value.as_bytes());
+    }
+    for value in ctx.libs {
+        hasher.update(value.as_bytes());
+    }
+    for value in ctx.cflags {
+        hasher.update(value.as_bytes());
+    }
+    for value in ctx.ldflags {
+        hasher.update(value.as_bytes());
+    }
+    let toml =
+        fs::read_to_string("dcr.toml").map_err(|err| format!("Failed to read dcr.toml: {err}"))?;
+    hasher.update(toml.as_bytes());
+    if let Ok(lock) = fs::read_to_string("dcr.lock") {
+        hasher.update(lock.as_bytes());
+    }
+    for source in sources {
+        let path = Path::new(source);
+        update_hasher_with_file(&mut hasher, path)?;
+    }
+    for header in headers {
+        update_hasher_with_file(&mut hasher, header)?;
+    }
+    for lib in lib_files {
+        update_hasher_with_file(&mut hasher, lib)?;
+    }
+    Ok(to_hex(&hasher.finalize()))
+}
+
+fn should_skip_build(ctx: &BuildContext, fingerprint: &str) -> bool {
+    let output = build_output_path(ctx);
+    if !Path::new(&output).is_file() {
+        return false;
+    }
+    let cache_path = build_cache_path(ctx.profile, ctx.target_dir);
+    let cached = fs::read_to_string(cache_path).unwrap_or_default();
+    cached.trim() == fingerprint
+}
+
+fn write_build_fingerprint(ctx: &BuildContext, fingerprint: &str) -> Result<(), String> {
+    let cache_path = build_cache_path(ctx.profile, ctx.target_dir);
+    if let Some(parent) = cache_path.parent() {
+        fs::create_dir_all(parent).map_err(|err| format!("Failed to create cache dir: {err}"))?;
+    }
+    fs::write(cache_path, format!("{fingerprint}\n"))
+        .map_err(|err| format!("Failed to write cache: {err}"))
+}
+
+fn build_cache_path(profile: &str, target_dir: Option<&str>) -> std::path::PathBuf {
+    match target_dir {
+        Some(dir) => Path::new(dir).join(format!(".dcr-build.{profile}.hash")),
+        None => Path::new("./target").join(profile).join(".dcr-build.hash"),
+    }
+}
+
+fn build_output_path(ctx: &BuildContext) -> String {
+    if ctx.kind == "staticlib" {
+        return crate::platform::lib_path(ctx.profile, ctx.project_name, ctx.target_dir);
+    }
+    if ctx.kind == "sharedlib" {
+        return crate::platform::shared_lib_path(ctx.profile, ctx.project_name, ctx.target_dir);
+    }
+    crate::platform::bin_path(ctx.profile, ctx.project_name, ctx.target_dir)
+}
+
+fn collect_header_files(
+    ctx: &BuildContext,
+    project_root: &Path,
+) -> Result<Vec<std::path::PathBuf>, String> {
+    let mut out = Vec::new();
+    let mut roots = Vec::new();
+    roots.push(project_root.join("src"));
+    for dir in ctx.include_dirs {
+        roots.push(Path::new(dir).to_path_buf());
+    }
+    for root in roots {
+        if !root.exists() {
+            continue;
+        }
+        collect_header_files_rec(&root, &mut out, ctx.exclude_dirs)?;
+    }
+    out.sort();
+    out.dedup();
+    Ok(out)
+}
+
+fn collect_header_files_rec(
+    dir: &Path,
+    out: &mut Vec<std::path::PathBuf>,
+    exclude_dirs: &[std::path::PathBuf],
+) -> Result<(), String> {
+    if is_excluded(dir, exclude_dirs) {
+        return Ok(());
+    }
+    for entry in fs::read_dir(dir).map_err(|err| format!("read_dir error: {err}"))? {
+        let entry = entry.map_err(|err| format!("read_dir error: {err}"))?;
+        let path = entry.path();
+        if path.is_dir() {
+            if is_excluded(&path, exclude_dirs) {
+                continue;
+            }
+            collect_header_files_rec(&path, out, exclude_dirs)?;
+            continue;
+        }
+        if !path.is_file() {
+            continue;
+        }
+        if is_header_file(&path) {
+            out.push(path);
+        }
+    }
+    Ok(())
+}
+
+fn is_header_file(path: &Path) -> bool {
+    let ext = path.extension().and_then(|v| v.to_str()).unwrap_or("");
+    matches!(ext, "h" | "hpp" | "hh" | "hxx" | "inc")
+}
+
+fn collect_lib_files(ctx: &BuildContext) -> Vec<std::path::PathBuf> {
+    let mut out = Vec::new();
+    for dir in ctx.lib_dirs {
+        let dir_path = Path::new(dir);
+        for lib in ctx.libs {
+            for candidate in lib_candidates(lib) {
+                let path = dir_path.join(candidate);
+                if path.is_file() {
+                    out.push(path);
+                }
+            }
+        }
+    }
+    out
+}
+
+fn lib_candidates(name: &str) -> Vec<String> {
+    if cfg!(target_os = "windows") {
+        return vec![format!("{name}.lib")];
+    }
+    if cfg!(target_os = "macos") {
+        return vec![
+            format!("lib{name}.a"),
+            format!("lib{name}.dylib"),
+            format!("lib{name}.so"),
+        ];
+    }
+    vec![
+        format!("lib{name}.a"),
+        format!("lib{name}.so"),
+        format!("lib{name}.so.0"),
+    ]
+}
+
+fn update_hasher_with_file(hasher: &mut Sha256, path: &Path) -> Result<(), String> {
+    hasher.update(path.to_string_lossy().as_bytes());
+    let meta = fs::metadata(path).map_err(|err| format!("source read error: {err}"))?;
+    hasher.update(meta.len().to_le_bytes());
+    if let Ok(modified) = meta.modified()
+        && let Ok(duration) = modified.duration_since(std::time::UNIX_EPOCH)
+    {
+        hasher.update(duration.as_nanos().to_le_bytes());
+    }
+    Ok(())
+}
+
+fn is_excluded(path: &Path, exclude_dirs: &[std::path::PathBuf]) -> bool {
+    exclude_dirs.iter().any(|dir| path.starts_with(dir))
+}
+
+fn to_hex(bytes: &[u8]) -> String {
+    let mut out = String::with_capacity(bytes.len() * 2);
+    for b in bytes {
+        out.push_str(&format!("{:02x}", b));
+    }
+    out
+}

src/cli/clean.rs

@@ -1,57 +1,120 @@
 use crate::config::flags;
-use crate::utils::fs::check_dir;
+use crate::core::config::Config;
+use crate::core::workspace::parse_workspace;
+use crate::utils::fs::{check_dir, find_project_root};
 use crate::utils::log::{error, warn};
 use crate::utils::text::{BOLD_GREEN, colored};
 use std::fs;
+use std::path::Path;
 
 pub fn clean(args: &[String]) -> i32 {
+    let start_dir = match std::env::current_dir() {
+        Ok(dir) => dir,
+        Err(_) => {
+            error("Failed to determine current directory");
+            return 1;
+        }
+    };
+    let root = match find_project_root(&start_dir) {
+        Ok(Some(dir)) => dir,
+        Ok(None) => {
+            error("dcr.toml file not found");
+            return 1;
+        }
+        Err(_) => {
+            error("Failed to find project root");
+            return 1;
+        }
+    };
+    let flags = match parse_clean_flags(args) {
+        Ok(v) => v,
+        Err(msg) => {
+            error(&msg);
+            return 1;
+        }
+    };
+
+    match with_dir(&root, || clean_from_root(&root, &flags)) {
+        Ok(()) => 0,
+        Err(msg) => {
+            error(&msg);
+            1
+        }
+    }
+}
+
+struct CleanFlags {
+    profile: Option<String>,
+    all: bool,
+}
+
+fn parse_clean_flags(args: &[String]) -> Result<CleanFlags, String> {
+    let mut profile: Option<String> = None;
+    let mut all = false;
+    for arg in args {
+        if arg == "--all" {
+            all = true;
+            continue;
+        }
+        if arg.starts_with("--") {
+            let candidate = arg.trim_start_matches("--").to_string();
+            if flags(&candidate).is_some() {
+                if profile.is_some() {
+                    return Err("Duplicate profile flag".to_string());
+                }
+                profile = Some(candidate);
+                continue;
+            }
+        }
+        return Err("Unknown argument".to_string());
+    }
+    Ok(CleanFlags { profile, all })
+}
+
+fn clean_from_root(root: &Path, flags: &CleanFlags) -> Result<(), String> {
+    let config = Config::open("./dcr.toml").map_err(|err| err.to_string())?;
+    if flags.all
+        && let Some(workspace) = parse_workspace(&config, root)?
+    {
+        for member in &workspace.members {
+            clean_project_at(&member.path, flags.profile.as_deref())?;
+        }
+    }
+    clean_project_at(root, flags.profile.as_deref())
+}
+
+fn clean_project_at(project_root: &Path, profile: Option<&str>) -> Result<(), String> {
+    with_dir(project_root, || {
         let project_name = std::env::current_dir()
             .ok()
             .and_then(|p| p.file_name().map(|v| v.to_string_lossy().to_string()))
             .unwrap_or_else(|| "project".to_string());
-    let items = check_dir(None).unwrap_or_default();
+        let items = check_dir(None).map_err(|_| "Failed to read project directory".to_string())?;
-
-    if args.len() > 1 {
-        error("Unknown argument");
-        return 1;
-    }
         if !items.contains(&"dcr.toml".to_string()) {
-        error("dcr.toml file not found");
+            return Err("dcr.toml file not found".to_string());
-        return 1;
         }
-
         println!(
             "    Cleaning project `{}`",
             colored(&project_name, BOLD_GREEN)
         );
         if !items.contains(&"target".to_string()) {
             warn("Directory target not found");
-        return 1;
+            return Ok(());
-    }
-
-    if let Some(arg) = args.first() {
-        let mut profile = arg.clone();
-        if profile.starts_with("--") {
-            profile = profile.trim_start_matches("--").to_string();
-        }
-        if flags(&profile).is_none() {
-            error("Unknown profile");
-            return 1;
         }
 
+        if let Some(profile) = profile {
             let target_items = check_dir(Some("target")).unwrap_or_default();
-        if !target_items.contains(&profile) {
+            if !target_items.contains(&profile.to_string()) {
                 warn(&format!("Directory target/{profile} not found"));
-            return 1;
+                return Ok(());
             }
-
+            println!("    Profile: {}", colored(profile, BOLD_GREEN));
-        println!("    Profile: {}", colored(&profile, BOLD_GREEN));
             let _ = fs::remove_dir_all(format!("target/{profile}"));
             println!(
                 "{} Removed directory target/{profile}",
                 colored("\n    ✔", BOLD_GREEN)
             );
-        return 0;
+            return Ok(());
         }
 
         let _ = fs::remove_dir_all("target");
@@ -59,5 +122,17 @@ pub fn clean(args: &[String]) -> i32 {
             "{} Removed directory target",
             colored("\n    ✔", BOLD_GREEN)
         );
-    0
+        Ok(())
+    })
+}
+
+fn with_dir<F, T>(dir: &Path, f: F) -> Result<T, String>
+where
+    F: FnOnce() -> Result<T, String>,
+{
+    let prev = std::env::current_dir().map_err(|_| "Failed to get current dir".to_string())?;
+    std::env::set_current_dir(dir).map_err(|_| "Failed to change directory".to_string())?;
+    let result = f();
+    let _ = std::env::set_current_dir(prev);
+    result
 }

src/cli/run.rs

@@ -2,23 +2,38 @@ use crate::cli::build::build;
 use crate::config::{PROFILE, flags};
 use crate::core::config::Config;
 use crate::core::runner::run_binary;
-use crate::utils::fs::check_dir;
+use crate::utils::fs::find_project_root;
 use crate::utils::log::{error, warn};
 use crate::utils::text::{BOLD_GREEN, colored};
+use std::path::Path;
 
 pub fn run(args: &[String]) -> i32 {
     let mut active_profile = PROFILE.to_string();
 
-    let items = check_dir(None).unwrap_or_default();
+    let start_dir = match std::env::current_dir() {
-    if !items.contains(&"dcr.toml".to_string()) {
+        Ok(dir) => dir,
+        Err(_) => {
+            error("Failed to determine current directory");
+            return 1;
+        }
+    };
+    let root = match find_project_root(&start_dir) {
+        Ok(Some(dir)) => dir,
+        Ok(None) => {
             error("dcr.toml file not found");
             return 1;
         }
-
-    let config = match Config::open("./dcr.toml") {
-        Ok(cfg) => cfg,
         Err(_) => {
-            error("dcr.toml file not found");
+            error("Failed to find project root");
+            return 1;
+        }
+    };
+    let config = match with_dir(&root, || {
+        Config::open("./dcr.toml").map_err(|err| err.to_string())
+    }) {
+        Ok(cfg) => cfg,
+        Err(err) => {
+            error(&err);
             return 1;
         }
     };
@@ -72,3 +87,14 @@ pub fn run(args: &[String]) -> i32 {
     error("Fix errors in the code to run the project");
     1
 }
+
+fn with_dir<F, T>(dir: &Path, f: F) -> Result<T, String>
+where
+    F: FnOnce() -> Result<T, String>,
+{
+    let prev = std::env::current_dir().map_err(|_| "Failed to get current dir".to_string())?;
+    std::env::set_current_dir(dir).map_err(|_| "Failed to change directory".to_string())?;
+    let result = f();
+    let _ = std::env::set_current_dir(prev);
+    result
+}

src/core/builder/common.rs

@@ -0,0 +1,421 @@
+use std::fs;
+use std::path::{Path, PathBuf};
+
+pub fn collect_sources(
+    extensions: &[&str],
+    exclude_dirs: &[PathBuf],
+) -> Result<Vec<String>, String> {
+    let mut sources = Vec::new();
+    collect_sources_rec("./src", extensions, &mut sources, exclude_dirs)?;
+    sources.sort();
+    if sources.is_empty() {
+        return Err("No source files found in ./src".to_string());
+    }
+    Ok(sources)
+}
+
+fn collect_sources_rec(
+    dir: &str,
+    extensions: &[&str],
+    out: &mut Vec<String>,
+    exclude_dirs: &[PathBuf],
+) -> Result<(), String> {
+    let dir_path = Path::new(dir);
+    let full_dir = if dir_path.is_absolute() {
+        dir_path.to_path_buf()
+    } else {
+        std::env::current_dir()
+            .map_err(|err| format!("src dir error: {err}"))?
+            .join(dir_path)
+    };
+    if is_excluded(&full_dir, exclude_dirs) {
+        return Ok(());
+    }
+    let entries = fs::read_dir(&full_dir).map_err(|err| format!("src dir error: {err}"))?;
+    for entry in entries {
+        let entry = entry.map_err(|err| format!("src dir error: {err}"))?;
+        let path = entry.path();
+        if path.is_dir() {
+            if is_excluded(&path, exclude_dirs) {
+                continue;
+            }
+            collect_sources_rec(&path.to_string_lossy(), extensions, out, exclude_dirs)?;
+            continue;
+        }
+        if !path.is_file() {
+            continue;
+        }
+        let ext_raw = path.extension().and_then(|v| v.to_str()).unwrap_or("");
+        let ext_lower = ext_raw.to_lowercase();
+        let matched = extensions
+            .iter()
+            .any(|allowed| *allowed == ext_raw || *allowed == ext_lower);
+        if matched {
+            out.push(normalize_source_path(&path));
+        }
+    }
+    Ok(())
+}
+
+pub fn is_excluded(path: &Path, exclude_dirs: &[PathBuf]) -> bool {
+    exclude_dirs.iter().any(|dir| path.starts_with(dir))
+}
+
+pub fn normalize_source_path(path: &Path) -> String {
+    if !path.is_absolute() {
+        return path.to_string_lossy().to_string();
+    }
+    if let Ok(base) = std::env::current_dir()
+        && let Ok(rel) = path.strip_prefix(&base)
+    {
+        return format!("./{}", rel.to_string_lossy());
+    }
+    path.to_string_lossy().to_string()
+}
+
+pub fn object_path(obj_dir: &Path, source: &str, obj_ext: &str) -> String {
+    let src_path = Path::new(source);
+    let rel = src_path
+        .strip_prefix("./src")
+        .or_else(|_| src_path.strip_prefix("src"))
+        .unwrap_or(src_path);
+    let mut out = obj_dir.join(rel);
+    out.set_extension(obj_ext.trim_start_matches('.'));
+    out.to_string_lossy().to_string()
+}
+
+pub fn needs_rebuild(source: &str, object: &str) -> bool {
+    let src_time = fs::metadata(source).and_then(|m| m.modified());
+    let obj_time = fs::metadata(object).and_then(|m| m.modified());
+    let o_time = match obj_time {
+        Ok(t) => t,
+        Err(_) => return true,
+    };
+    match src_time {
+        Ok(s) if s > o_time => return true,
+        Err(_) => return true,
+        _ => {}
+    }
+
+    let d_file = PathBuf::from(object).with_extension("d");
+    if let Ok(content) = fs::read_to_string(&d_file) {
+        let deps = parse_d_file(&content);
+        for dep in deps {
+            let dep_path = Path::new(&dep);
+            if dep_path == Path::new(object) || dep_path == Path::new(source) {
+                continue;
+            }
+            if let Ok(dep_meta) = fs::metadata(dep_path) {
+                if let Ok(dep_time) = dep_meta.modified()
+                    && dep_time > o_time
+                {
+                    return true;
+                }
+            } else {
+                return true; // Missing dependency triggers rebuild
+            }
+        }
+    }
+    false
+}
+
+fn parse_d_file(content: &str) -> Vec<String> {
+    let mut deps = Vec::new();
+    let text = content.replace("\\\n", " ").replace("\\\r\n", " ");
+    let mut target_end = 0;
+    let chars: Vec<char> = text.chars().collect();
+    for i in 0..chars.len() {
+        if chars[i] == ':' {
+            if i == 1
+                && chars[0].is_ascii_alphabetic()
+                && i + 1 < chars.len()
+                && (chars[i + 1] == '\\' || chars[i + 1] == '/')
+            {
+                continue; // Windows drive letter
+            }
+            target_end = i + 1;
+            break;
+        }
+    }
+
+    let deps_str = if target_end > 0 {
+        &text[target_end..]
+    } else {
+        &text
+    };
+
+    let mut current_path = String::new();
+    let mut in_escape = false;
+
+    for c in deps_str.chars() {
+        if in_escape {
+            if c != '\n' && c != '\r' {
+                current_path.push(c);
+            }
+            in_escape = false;
+        } else if c == '\\' {
+            in_escape = true;
+        } else if c.is_whitespace() {
+            if !current_path.is_empty() {
+                deps.push(current_path.clone());
+                current_path.clear();
+            }
+        } else {
+            current_path.push(c);
+        }
+    }
+    if !current_path.is_empty() {
+        deps.push(current_path);
+    }
+    deps
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::fs;
+    use std::path::PathBuf;
+    use std::sync::atomic::{AtomicUsize, Ordering};
+
+    static TEST_COUNTER: AtomicUsize = AtomicUsize::new(0);
+
+    fn temp_dir(prefix: &str) -> PathBuf {
+        let n = TEST_COUNTER.fetch_add(1, Ordering::SeqCst);
+        let dir = std::env::temp_dir().join(format!("dcr_test_{prefix}_{n}"));
+        let _ = fs::remove_dir_all(&dir);
+        fs::create_dir_all(&dir).unwrap();
+        dir
+    }
+
+    #[test]
+    fn object_path_basic() {
+        let obj_dir = Path::new("target/debug/obj");
+        let result = object_path(obj_dir, "./src/main.c", "o");
+        assert_eq!(result, "target/debug/obj/main.o");
+    }
+
+    #[test]
+    fn object_path_nested() {
+        let obj_dir = Path::new("target/debug/obj");
+        let result = object_path(obj_dir, "./src/core/utils.c", "o");
+        assert_eq!(result, "target/debug/obj/core/utils.o");
+    }
+
+    #[test]
+    fn object_path_no_prefix() {
+        let obj_dir = Path::new("target/debug/obj");
+        let result = object_path(obj_dir, "src/main.c", "o");
+        assert_eq!(result, "target/debug/obj/main.o");
+    }
+
+    #[test]
+    fn object_path_msvc_ext() {
+        let obj_dir = Path::new("target/debug/obj");
+        let result = object_path(obj_dir, "./src/main.c", "obj");
+        assert_eq!(result, "target/debug/obj/main.obj");
+    }
+
+    #[test]
+    fn needs_rebuild_no_object() {
+        let dir = temp_dir("rebuild_no_obj");
+        let src = dir.join("test.c");
+        fs::write(&src, "int main() {}").unwrap();
+        let obj = dir.join("test.o");
+        assert!(needs_rebuild(
+            &src.to_string_lossy(),
+            &obj.to_string_lossy()
+        ));
+    }
+
+    #[test]
+    fn needs_rebuild_fresh() {
+        let dir = temp_dir("rebuild_fresh");
+        let src = dir.join("test.c");
+        let obj = dir.join("test.o");
+        fs::write(&src, "int main() {}").unwrap();
+        // Sleep briefly to ensure mtime difference
+        std::thread::sleep(std::time::Duration::from_millis(50));
+        fs::write(&obj, "").unwrap();
+        assert!(!needs_rebuild(
+            &src.to_string_lossy(),
+            &obj.to_string_lossy()
+        ));
+    }
+
+    #[test]
+    fn needs_rebuild_stale() {
+        let dir = temp_dir("rebuild_stale");
+        let src = dir.join("test.c");
+        let obj = dir.join("test.o");
+        fs::write(&obj, "").unwrap();
+        std::thread::sleep(std::time::Duration::from_millis(50));
+        fs::write(&src, "int main() { return 1; }").unwrap();
+        assert!(needs_rebuild(
+            &src.to_string_lossy(),
+            &obj.to_string_lossy()
+        ));
+    }
+
+    #[test]
+    fn is_excluded_match() {
+        let excluded = vec![PathBuf::from("/project/src/vendor")];
+        assert!(is_excluded(Path::new("/project/src/vendor"), &excluded));
+        assert!(is_excluded(
+            Path::new("/project/src/vendor/lib.c"),
+            &excluded
+        ));
+    }
+
+    #[test]
+    fn is_excluded_no_match() {
+        let excluded = vec![PathBuf::from("/project/src/vendor")];
+        assert!(!is_excluded(Path::new("/project/src/main.c"), &excluded));
+        assert!(!is_excluded(Path::new("/other/vendor"), &excluded));
+    }
+
+    #[test]
+    fn collect_sources_c_files() {
+        let dir = temp_dir("collect_c");
+        let src = dir.join("src");
+        fs::create_dir_all(&src).unwrap();
+        fs::write(src.join("main.c"), "").unwrap();
+        fs::write(src.join("utils.c"), "").unwrap();
+        fs::write(src.join("README.md"), "").unwrap(); // should be ignored
+
+        let prev = std::env::current_dir().unwrap();
+        std::env::set_current_dir(&dir).unwrap();
+        let result = collect_sources(&["c"], &[]);
+        std::env::set_current_dir(prev).unwrap();
+
+        let sources = result.expect("should find sources");
+        assert_eq!(sources.len(), 2);
+        assert!(sources.iter().any(|s| s.ends_with("main.c")));
+        assert!(sources.iter().any(|s| s.ends_with("utils.c")));
+    }
+
+    #[test]
+    fn collect_sources_cpp_files() {
+        let dir = temp_dir("collect_cpp");
+        let src = dir.join("src");
+        fs::create_dir_all(&src).unwrap();
+        fs::write(src.join("main.cpp"), "").unwrap();
+        fs::write(src.join("helper.cxx"), "").unwrap();
+        fs::write(src.join("other.cc"), "").unwrap();
+        fs::write(src.join("skip.c"), "").unwrap(); // should be ignored
+
+        let prev = std::env::current_dir().unwrap();
+        std::env::set_current_dir(&dir).unwrap();
+        let result = collect_sources(&["cpp", "cxx", "cc"], &[]);
+        std::env::set_current_dir(prev).unwrap();
+
+        let sources = result.expect("should find sources");
+        assert_eq!(sources.len(), 3);
+    }
+
+    #[test]
+    fn collect_sources_empty_dir() {
+        let dir = temp_dir("collect_empty");
+        let src = dir.join("src");
+        fs::create_dir_all(&src).unwrap();
+
+        let prev = std::env::current_dir().unwrap();
+        std::env::set_current_dir(&dir).unwrap();
+        let result = collect_sources(&["c"], &[]);
+        std::env::set_current_dir(prev).unwrap();
+
+        assert!(result.is_err(), "empty src should return error");
+    }
+
+    #[test]
+    fn collect_sources_respects_excludes() {
+        let dir = temp_dir("collect_exclude");
+        let src = dir.join("src");
+        let vendor = src.join("vendor");
+        fs::create_dir_all(&vendor).unwrap();
+        fs::write(src.join("main.c"), "").unwrap();
+        fs::write(vendor.join("lib.c"), "").unwrap(); // should be excluded
+
+        let exclude = vec![vendor.clone()];
+        let prev = std::env::current_dir().unwrap();
+        std::env::set_current_dir(&dir).unwrap();
+        let result = collect_sources(&["c"], &exclude);
+        std::env::set_current_dir(prev).unwrap();
+
+        let sources = result.expect("should find sources");
+        assert_eq!(sources.len(), 1);
+        assert!(sources[0].ends_with("main.c"));
+    }
+
+    #[test]
+    fn collect_sources_nested() {
+        let dir = temp_dir("collect_nested");
+        let src = dir.join("src");
+        let sub = src.join("core").join("deep");
+        fs::create_dir_all(&sub).unwrap();
+        fs::write(src.join("main.c"), "").unwrap();
+        fs::write(sub.join("nested.c"), "").unwrap();
+
+        let prev = std::env::current_dir().unwrap();
+        std::env::set_current_dir(&dir).unwrap();
+        let result = collect_sources(&["c"], &[]);
+        std::env::set_current_dir(prev).unwrap();
+
+        let sources = result.expect("should find sources");
+        assert_eq!(sources.len(), 2);
+    }
+
+    #[test]
+    fn normalize_relative_path() {
+        let result = normalize_source_path(Path::new("./src/main.c"));
+        assert_eq!(result, "./src/main.c");
+    }
+
+    #[test]
+    fn parse_d_file_gcc_format() {
+        let content = "target/obj/main.o: src/main.c src/utils.h \\\n src/core/types.h";
+        let deps = parse_d_file(content);
+        assert_eq!(deps, vec!["src/main.c", "src/utils.h", "src/core/types.h"]);
+    }
+
+    #[test]
+    fn parse_d_file_msvc_format() {
+        let content = "target/obj/main.obj: \\\n  C:/sdk/include/windows.h \\\n  src/main.c";
+        let deps = parse_d_file(content);
+        assert_eq!(deps, vec!["C:/sdk/include/windows.h", "src/main.c"]);
+    }
+
+    #[test]
+    fn needs_rebuild_header_modified() {
+        let dir = temp_dir("rebuild_header");
+        let src = dir.join("test.c");
+        let header = dir.join("test.h");
+        let obj = dir.join("test.o");
+        let d_file = dir.join("test.d");
+
+        fs::write(&src, "int main() {}").unwrap();
+        fs::write(&header, "#define A 1").unwrap();
+        std::thread::sleep(std::time::Duration::from_millis(50));
+        fs::write(&obj, "").unwrap();
+
+        let d_content = format!(
+            "{}: {} {}",
+            obj.to_string_lossy(),
+            src.to_string_lossy(),
+            header.to_string_lossy()
+        );
+        fs::write(&d_file, d_content).unwrap();
+
+        assert!(
+            !needs_rebuild(&src.to_string_lossy(), &obj.to_string_lossy()),
+            "should be fresh"
+        );
+
+        std::thread::sleep(std::time::Duration::from_millis(50));
+        fs::write(&header, "#define A 2").unwrap(); // modify header
+
+        assert!(
+            needs_rebuild(&src.to_string_lossy(), &obj.to_string_lossy()),
+            "changed header should trigger rebuild"
+        );
+    }
+}

src/core/builder/gas.rs

@@ -1,4 +1,5 @@
 use crate::core::builder::BuildContext;
+use crate::core::builder::common;
 use crate::platform;
 use std::fs;
 use std::path::Path;
@@ -15,18 +16,19 @@ pub fn build(ctx: &BuildContext) -> Result<f64, String> {
         ctx.compiler
     };
     let start_time = Instant::now();
-    let sources = collect_sources(ctx.language)?;
+    let sources = collect_sources(ctx)?;
     let obj_dir = Path::new("./target").join(ctx.profile).join("obj");
     let objects = build_objects(assembler, &sources, &obj_dir, ctx, "o")?;
 
     if ctx.kind == "staticlib" {
         let lib_path = platform::lib_path(ctx.profile, ctx.project_name, ctx.target_dir);
-        let mut cmd = Command::new(if cfg!(target_os = "windows") {
+        let archiver = ctx.archiver.unwrap_or(if cfg!(target_os = "windows") {
             "lib"
         } else {
             "ar"
         });
-        if cfg!(target_os = "windows") {
+        let mut cmd = Command::new(archiver);
+        if cfg!(target_os = "windows") && archiver == "lib" {
             cmd.arg("/nologo").arg(format!("/OUT:{lib_path}"));
         } else {
             cmd.arg("rcs").arg(&lib_path);
@@ -44,7 +46,7 @@ pub fn build(ctx: &BuildContext) -> Result<f64, String> {
         }
     }
 
-    let mut cmd = Command::new("cc");
+    let mut cmd = Command::new(ctx.linker.unwrap_or("cc"));
     if ctx.kind == "sharedlib" {
         if cfg!(target_os = "macos") {
             cmd.arg("-dynamiclib");
@@ -81,38 +83,9 @@ pub fn build(ctx: &BuildContext) -> Result<f64, String> {
     }
 }
 
-fn collect_sources(language: &str) -> Result<Vec<String>, String> {
+pub(crate) fn collect_sources(ctx: &BuildContext) -> Result<Vec<String>, String> {
-    let lang = language.to_lowercase();
+    // GAS handles only lowercase .s files
-    let mut sources = Vec::new();
+    common::collect_sources(&["s"], ctx.exclude_dirs)
-    collect_sources_rec("./src", &lang, &mut sources)?;
-    sources.sort();
-    if sources.is_empty() {
-        return Err("No source files found in ./src".to_string());
-    }
-    Ok(sources)
-}
-
-fn collect_sources_rec(dir: &str, lang: &str, out: &mut Vec<String>) -> Result<(), String> {
-    let entries = fs::read_dir(dir).map_err(|err| format!("src dir error: {err}"))?;
-    for entry in entries {
-        let entry = entry.map_err(|err| format!("src dir error: {err}"))?;
-        let path = entry.path();
-        if path.is_dir() {
-            collect_sources_rec(&path.to_string_lossy(), lang, out)?;
-            continue;
-        }
-        if !path.is_file() {
-            continue;
-        }
-        let ext_raw = path.extension().and_then(|v| v.to_str()).unwrap_or("");
-        let ext = ext_raw.to_lowercase();
-        let file = path.to_string_lossy().to_string();
-        let allowed = lang == "asm" && ext == "s" && ext_raw == "s";
-        if allowed {
-            out.push(file);
-        }
-    }
-    Ok(())
 }
 
 fn build_objects(
@@ -124,11 +97,11 @@ fn build_objects(
 ) -> Result<Vec<String>, String> {
     let mut objects = Vec::new();
     for source in sources {
-        let obj_path = object_path(obj_dir, source, obj_ext);
+        let obj_path = common::object_path(obj_dir, source, obj_ext);
         if let Some(parent) = Path::new(&obj_path).parent() {
             fs::create_dir_all(parent).map_err(|err| format!("obj dir error: {err}"))?;
         }
-        if needs_rebuild(source, &obj_path) {
+        if common::needs_rebuild(source, &obj_path) {
             let mut cmd = Command::new(assembler);
             cmd.arg(source).arg("-o").arg(&obj_path);
             for flag in ctx.cflags {
@@ -144,24 +117,3 @@ fn build_objects(
     }
     Ok(objects)
 }
-
-fn object_path(obj_dir: &Path, source: &str, obj_ext: &str) -> String {
-    let src_path = Path::new(source);
-    let rel = src_path
-        .strip_prefix("./src")
-        .or_else(|_| src_path.strip_prefix("src"))
-        .unwrap_or(src_path);
-    let mut out = obj_dir.join(rel);
-    out.set_extension(obj_ext.trim_start_matches('.'));
-    out.to_string_lossy().to_string()
-}
-
-fn needs_rebuild(source: &str, object: &str) -> bool {
-    let src_time = fs::metadata(source).and_then(|m| m.modified());
-    let obj_time = fs::metadata(object).and_then(|m| m.modified());
-    match (src_time, obj_time) {
-        (Ok(s), Ok(o)) => s > o,
-        (Ok(_), Err(_)) => true,
-        _ => true,
-    }
-}

src/core/builder/gcc.rs

@@ -1,200 +0,0 @@
-use crate::core::builder::BuildContext;
-use crate::platform;
-use std::fs;
-use std::path::Path;
-use std::process::Command;
-use std::time::Instant;
-
-pub fn build(ctx: &BuildContext) -> Result<f64, String> {
-    let compiler = if ctx.compiler.is_empty() {
-        "cc"
-    } else {
-        ctx.compiler
-    };
-    let start_time = Instant::now();
-    let sources = collect_sources(ctx.language)?;
-    let obj_dir = Path::new("./target").join(ctx.profile).join("obj");
-    let objects = build_objects(compiler, &sources, &obj_dir, ctx, "o")?;
-
-    if ctx.kind == "staticlib" {
-        let lib_path = platform::lib_path(ctx.profile, ctx.project_name, ctx.target_dir);
-        let mut cmd = Command::new("ar");
-        cmd.arg("rcs").arg(&lib_path);
-        for obj in &objects {
-            cmd.arg(obj);
-        }
-        match cmd.status() {
-            Ok(status) if status.success() => {
-                let elapsed = ((start_time.elapsed().as_secs_f64() * 100.0).trunc()) / 100.0;
-                return Ok(elapsed);
-            }
-            Ok(_) => return Err("Build failed".to_string()),
-            Err(err) => return Err(format!("Build failed: {err}")),
-        }
-    }
-
-    let mut cmd = Command::new(compiler);
-    if ctx.kind == "sharedlib" {
-        if cfg!(target_os = "macos") {
-            cmd.arg("-dynamiclib");
-        } else {
-            cmd.arg("-shared");
-        }
-    }
-    for obj in &objects {
-        cmd.arg(obj);
-    }
-    for flag in default_flags(ctx.profile) {
-        cmd.arg(flag);
-    }
-    for flag in ctx.cflags {
-        cmd.arg(flag);
-    }
-    for dir in ctx.lib_dirs {
-        cmd.arg(format!("-L{dir}"));
-    }
-    for lib in ctx.libs {
-        cmd.arg(format!("-l{lib}"));
-    }
-    for flag in ctx.ldflags {
-        cmd.arg(flag);
-    }
-    let out_path = if ctx.kind == "sharedlib" {
-        platform::shared_lib_path(ctx.profile, ctx.project_name, ctx.target_dir)
-    } else {
-        platform::bin_path(ctx.profile, ctx.project_name, ctx.target_dir)
-    };
-    cmd.arg("-o").arg(out_path);
-
-    match cmd.status() {
-        Ok(status) if status.success() => {
-            let elapsed = ((start_time.elapsed().as_secs_f64() * 100.0).trunc()) / 100.0;
-            Ok(elapsed)
-        }
-        Ok(_) => Err("Build failed".to_string()),
-        Err(err) => Err(format!("Build failed: {err}")),
-    }
-}
-
-fn collect_sources(language: &str) -> Result<Vec<String>, String> {
-    let lang = language.to_lowercase();
-    let mut sources = Vec::new();
-    collect_sources_rec("./src", &lang, &mut sources)?;
-    sources.sort();
-    if sources.is_empty() {
-        return Err("No source files found in ./src".to_string());
-    }
-    Ok(sources)
-}
-
-fn collect_sources_rec(dir: &str, lang: &str, out: &mut Vec<String>) -> Result<(), String> {
-    let entries = fs::read_dir(dir).map_err(|err| format!("src dir error: {err}"))?;
-    for entry in entries {
-        let entry = entry.map_err(|err| format!("src dir error: {err}"))?;
-        let path = entry.path();
-        if path.is_dir() {
-            collect_sources_rec(&path.to_string_lossy(), lang, out)?;
-            continue;
-        }
-        if !path.is_file() {
-            continue;
-        }
-        let ext = path
-            .extension()
-            .and_then(|v| v.to_str())
-            .unwrap_or("")
-            .to_lowercase();
-        let file = path.to_string_lossy().to_string();
-        let allowed = (lang == "c" && ext == "c")
-            || ((lang == "c++" || lang == "cpp" || lang == "cxx")
-                && (ext == "cpp" || ext == "cxx" || ext == "cc"))
-            || (lang == "asm" && (ext == "s" || ext == "asm"));
-        if allowed {
-            out.push(file);
-        }
-    }
-    Ok(())
-}
-
-fn default_flags(profile: &str) -> &'static [&'static str] {
-    match profile {
-        "release" => &["-O3", "-DNDEBUG", "-march=native"],
-        "debug" => &[
-            "-O0",
-            "-g",
-            "-Wall",
-            "-Wextra",
-            "-fno-omit-frame-pointer",
-            "-DDEBUG",
-        ],
-        _ => &[],
-    }
-}
-
-fn build_objects(
-    compiler: &str,
-    sources: &[String],
-    obj_dir: &Path,
-    ctx: &BuildContext,
-    obj_ext: &str,
-) -> Result<Vec<String>, String> {
-    let mut objects = Vec::new();
-    for source in sources {
-        let obj_path = object_path(obj_dir, source, obj_ext);
-        if let Some(parent) = Path::new(&obj_path).parent() {
-            fs::create_dir_all(parent).map_err(|err| format!("obj dir error: {err}"))?;
-        }
-        if needs_rebuild(source, &obj_path) {
-            let mut cmd = Command::new(compiler);
-            cmd.arg("-c").arg(source).arg("-o").arg(&obj_path);
-            if ctx.kind == "sharedlib" {
-                cmd.arg("-fPIC");
-            }
-            if let Some(platform) = ctx.platform
-                && !platform.trim().is_empty()
-            {
-                cmd.arg(format!("-march={}", platform));
-            }
-            if !ctx.standard.is_empty() && ctx.language.to_lowercase() != "asm" {
-                cmd.arg(format!("-std={}", ctx.standard));
-            }
-            for flag in default_flags(ctx.profile) {
-                cmd.arg(flag);
-            }
-            for flag in ctx.cflags {
-                cmd.arg(flag);
-            }
-            for dir in ctx.include_dirs {
-                cmd.arg(format!("-I{dir}"));
-            }
-            match cmd.status() {
-                Ok(status) if status.success() => {}
-                Ok(_) => return Err("Build failed".to_string()),
-                Err(err) => return Err(format!("Build failed: {err}")),
-            }
-        }
-        objects.push(obj_path);
-    }
-    Ok(objects)
-}
-
-fn object_path(obj_dir: &Path, source: &str, obj_ext: &str) -> String {
-    let src_path = Path::new(source);
-    let rel = src_path
-        .strip_prefix("./src")
-        .or_else(|_| src_path.strip_prefix("src"))
-        .unwrap_or(src_path);
-    let mut out = obj_dir.join(rel);
-    out.set_extension(obj_ext.trim_start_matches('.'));
-    out.to_string_lossy().to_string()
-}
-
-fn needs_rebuild(source: &str, object: &str) -> bool {
-    let src_time = fs::metadata(source).and_then(|m| m.modified());
-    let obj_time = fs::metadata(object).and_then(|m| m.modified());
-    match (src_time, obj_time) {
-        (Ok(s), Ok(o)) => s > o,
-        (Ok(_), Err(_)) => true,
-        _ => true,
-    }
-}

src/core/builder/mod.rs

@@ -1,8 +1,8 @@
-pub mod clang;
+pub mod common;
 pub mod gas;
-pub mod gcc;
 pub mod msvc;
 pub mod nasm;
+pub mod unix_cc;
 
 pub struct BuildContext<'a> {
     pub profile: &'a str,
@@ -13,6 +13,9 @@ pub struct BuildContext<'a> {
     pub target_dir: Option<&'a str>,
     pub kind: &'a str,
     pub platform: Option<&'a str>,
+    pub linker: Option<&'a str>,
+    pub archiver: Option<&'a str>,
+    pub exclude_dirs: &'a [std::path::PathBuf],
     pub include_dirs: &'a [String],
     pub lib_dirs: &'a [String],
     pub libs: &'a [String],
@@ -31,14 +34,22 @@ pub fn build(ctx: &BuildContext) -> Result<f64, String> {
     if compiler.contains("nasm") {
         return nasm::build(ctx);
     }
-    if compiler.contains("gcc") || compiler.contains("g++") {
-        return gcc::build(ctx);
-    }
-    if compiler.contains("clang") || compiler.contains("clang++") {
-        return clang::build(ctx);
-    }
     if compiler == "cl" || compiler.contains("msvc") {
         return msvc::build(ctx);
     }
-    clang::build(ctx)
+    unix_cc::build(ctx)
+}
+
+pub fn collect_sources(ctx: &BuildContext) -> Result<Vec<String>, String> {
+    let compiler = ctx.compiler.to_lowercase();
+    if compiler.contains("clang-cl") || compiler == "cl" || compiler.contains("msvc") {
+        return msvc::collect_sources(ctx);
+    }
+    if compiler == "as" || compiler.contains("gas") {
+        return gas::collect_sources(ctx);
+    }
+    if compiler.contains("nasm") {
+        return nasm::collect_sources(ctx);
+    }
+    unix_cc::collect_sources(ctx)
 }

src/core/builder/msvc.rs

@@ -1,4 +1,5 @@
 use crate::core::builder::BuildContext;
+use crate::core::builder::common;
 use crate::platform;
 use std::fs;
 use std::path::Path;
@@ -15,13 +16,13 @@ pub fn build(ctx: &BuildContext) -> Result<f64, String> {
         return Err("MSVC backend does not support build.language = \"asm\"".to_string());
     }
     let start_time = Instant::now();
-    let sources = collect_sources(ctx.language)?;
+    let sources = collect_sources(ctx)?;
     let obj_dir = Path::new("./target").join(ctx.profile).join("obj");
     let objects = build_objects(compiler, &sources, &obj_dir, ctx, "obj")?;
 
     if ctx.kind == "staticlib" {
         let lib_path = platform::lib_path(ctx.profile, ctx.project_name, ctx.target_dir);
-        let mut cmd = Command::new("lib");
+        let mut cmd = Command::new(ctx.archiver.unwrap_or("lib"));
         cmd.arg("/nologo").arg(format!("/OUT:{lib_path}"));
         for obj in &objects {
             cmd.arg(obj);
@@ -100,44 +101,18 @@ pub fn build(ctx: &BuildContext) -> Result<f64, String> {
     }
 }
 
-fn collect_sources(language: &str) -> Result<Vec<String>, String> {
+pub(crate) fn collect_sources(ctx: &BuildContext) -> Result<Vec<String>, String> {
-    let lang = language.to_lowercase();
+    let extensions = source_extensions(ctx.language);
-    let mut sources = Vec::new();
+    common::collect_sources(&extensions, ctx.exclude_dirs)
-    collect_sources_rec("./src", &lang, &mut sources)?;
-    sources.sort();
-    if sources.is_empty() {
-        return Err("No source files found in ./src".to_string());
-    }
-    Ok(sources)
 }
 
-fn collect_sources_rec(dir: &str, lang: &str, out: &mut Vec<String>) -> Result<(), String> {
+fn source_extensions(language: &str) -> Vec<&str> {
-    let entries = fs::read_dir(dir).map_err(|err| format!("src dir error: {err}"))?;
+    let lang = language.to_lowercase();
-    for entry in entries {
+    match lang.as_str() {
-        let entry = entry.map_err(|err| format!("src dir error: {err}"))?;
+        "c" => vec!["c"],
-        let path = entry.path();
+        "c++" | "cpp" | "cxx" => vec!["cpp", "cxx", "cc"],
-        if path.is_dir() {
+        _ => vec!["c"],
-            collect_sources_rec(&path.to_string_lossy(), lang, out)?;
-            continue;
     }
-        if !path.is_file() {
-            continue;
-        }
-        let ext = path
-            .extension()
-            .and_then(|v| v.to_str())
-            .unwrap_or("")
-            .to_lowercase();
-        let file = path.to_string_lossy().to_string();
-        let allowed = (lang == "c" && ext == "c")
-            || ((lang == "c++" || lang == "cpp" || lang == "cxx")
-                && (ext == "cpp" || ext == "cxx" || ext == "cc"))
-            || (lang == "asm" && (ext == "s" || ext == "asm"));
-        if allowed {
-            out.push(file);
-        }
-    }
-    Ok(())
 }
 
 fn msvc_standard_flag(language: &str, standard: &str) -> Result<String, String> {
@@ -197,11 +172,11 @@ fn build_objects(
 ) -> Result<Vec<String>, String> {
     let mut objects = Vec::new();
     for source in sources {
-        let obj_path = object_path(obj_dir, source, obj_ext);
+        let obj_path = common::object_path(obj_dir, source, obj_ext);
         if let Some(parent) = Path::new(&obj_path).parent() {
             fs::create_dir_all(parent).map_err(|err| format!("obj dir error: {err}"))?;
         }
-        if needs_rebuild(source, &obj_path) {
+        if common::needs_rebuild(source, &obj_path) {
             let mut cmd = Command::new(compiler);
             cmd.arg("/nologo");
             match ctx.language.to_lowercase().as_str() {
@@ -232,34 +207,54 @@ fn build_objects(
                 cmd.arg(format!("/I{dir}"));
             }
             cmd.arg("/c").arg(source).arg(format!("/Fo:{}", obj_path));
-            match cmd.status() {
+            cmd.arg("/showIncludes");
-                Ok(status) if status.success() => {}
+
-                Ok(_) => return Err("Build failed".to_string()),
+            let output = cmd.output().map_err(|err| format!("Build failed: {err}"))?;
-                Err(err) => return Err(format!("Build failed: {err}")),
+            let stdout = String::from_utf8_lossy(&output.stdout);
+            let stderr = String::from_utf8_lossy(&output.stderr);
+
+            let mut headers = Vec::new();
+            let mut clean_stdout = String::new();
+            for line in stdout.lines() {
+                if let Some(stripped) = line.strip_prefix("Note: including file:") {
+                    headers.push(stripped.trim().to_string());
+                } else if let Some(stripped) = line.strip_prefix("Примечание: включение файла:")
+                {
+                    headers.push(stripped.trim().to_string());
+                } else {
+                    clean_stdout.push_str(line);
+                    clean_stdout.push('\n');
                 }
             }
+
+            if !output.status.success() {
+                eprint!("{}", clean_stdout);
+                eprint!("{}", stderr);
+                return Err("Build failed".to_string());
+            } else {
+                let trimmed_out = clean_stdout.trim();
+                let trimmed_err = stderr.trim();
+                let src_filename = Path::new(source)
+                    .file_name()
+                    .and_then(|v| v.to_str())
+                    .unwrap_or("");
+                if !trimmed_out.is_empty() && trimmed_out != src_filename {
+                    print!("{}", clean_stdout);
+                }
+                if !trimmed_err.is_empty() {
+                    eprintln!("{}", trimmed_err);
+                }
+            }
+
+            let d_path = Path::new(&obj_path).with_extension("d");
+            let mut d_content = format!("{}: \\\n", obj_path.replace('\\', "/"));
+            for h in headers {
+                let escaped = h.replace('\\', "/").replace(" ", "\\ ");
+                d_content.push_str(&format!("  {} \\\n", escaped));
+            }
+            std::fs::write(&d_path, d_content).map_err(|err| format!("d file error: {err}"))?;
+        }
         objects.push(obj_path);
     }
     Ok(objects)
 }
-
-fn object_path(obj_dir: &Path, source: &str, obj_ext: &str) -> String {
-    let src_path = Path::new(source);
-    let rel = src_path
-        .strip_prefix("./src")
-        .or_else(|_| src_path.strip_prefix("src"))
-        .unwrap_or(src_path);
-    let mut out = obj_dir.join(rel);
-    out.set_extension(obj_ext.trim_start_matches('.'));
-    out.to_string_lossy().to_string()
-}
-
-fn needs_rebuild(source: &str, object: &str) -> bool {
-    let src_time = fs::metadata(source).and_then(|m| m.modified());
-    let obj_time = fs::metadata(object).and_then(|m| m.modified());
-    match (src_time, obj_time) {
-        (Ok(s), Ok(o)) => s > o,
-        (Ok(_), Err(_)) => true,
-        _ => true,
-    }
-}

src/core/builder/nasm.rs

@@ -1,4 +1,5 @@
 use crate::core::builder::BuildContext;
+use crate::core::builder::common;
 use crate::platform;
 use std::fs;
 use std::path::Path;
@@ -15,18 +16,19 @@ pub fn build(ctx: &BuildContext) -> Result<f64, String> {
         ctx.compiler
     };
     let start_time = Instant::now();
-    let sources = collect_sources(ctx.language)?;
+    let sources = collect_sources(ctx)?;
     let obj_dir = Path::new("./target").join(ctx.profile).join("obj");
     let objects = build_objects(assembler, &sources, &obj_dir, ctx, "o")?;
 
     if ctx.kind == "staticlib" {
         let lib_path = platform::lib_path(ctx.profile, ctx.project_name, ctx.target_dir);
-        let mut cmd = Command::new(if cfg!(target_os = "windows") {
+        let archiver = ctx.archiver.unwrap_or(if cfg!(target_os = "windows") {
             "lib"
         } else {
             "ar"
         });
-        if cfg!(target_os = "windows") {
+        let mut cmd = Command::new(archiver);
+        if cfg!(target_os = "windows") && archiver == "lib" {
             cmd.arg("/nologo").arg(format!("/OUT:{lib_path}"));
         } else {
             cmd.arg("rcs").arg(&lib_path);
@@ -44,8 +46,7 @@ pub fn build(ctx: &BuildContext) -> Result<f64, String> {
         }
     }
 
-    let linker = "cc";
+    let mut cmd = Command::new(ctx.linker.unwrap_or("cc"));
-    let mut cmd = Command::new(linker);
     if ctx.kind == "sharedlib" {
         if cfg!(target_os = "macos") {
             cmd.arg("-dynamiclib");
@@ -82,38 +83,9 @@ pub fn build(ctx: &BuildContext) -> Result<f64, String> {
     }
 }
 
-fn collect_sources(language: &str) -> Result<Vec<String>, String> {
+pub(crate) fn collect_sources(ctx: &BuildContext) -> Result<Vec<String>, String> {
-    let lang = language.to_lowercase();
+    // NASM handles lowercase .s and .asm only (not .S which is GCC preprocessed)
-    let mut sources = Vec::new();
+    common::collect_sources(&["asm", "s"], ctx.exclude_dirs)
-    collect_sources_rec("./src", &lang, &mut sources)?;
-    sources.sort();
-    if sources.is_empty() {
-        return Err("No source files found in ./src".to_string());
-    }
-    Ok(sources)
-}
-
-fn collect_sources_rec(dir: &str, lang: &str, out: &mut Vec<String>) -> Result<(), String> {
-    let entries = fs::read_dir(dir).map_err(|err| format!("src dir error: {err}"))?;
-    for entry in entries {
-        let entry = entry.map_err(|err| format!("src dir error: {err}"))?;
-        let path = entry.path();
-        if path.is_dir() {
-            collect_sources_rec(&path.to_string_lossy(), lang, out)?;
-            continue;
-        }
-        if !path.is_file() {
-            continue;
-        }
-        let ext_raw = path.extension().and_then(|v| v.to_str()).unwrap_or("");
-        let ext = ext_raw.to_lowercase();
-        let file = path.to_string_lossy().to_string();
-        let allowed = lang == "asm" && (ext == "asm" || (ext == "s" && ext_raw == "s"));
-        if allowed {
-            out.push(file);
-        }
-    }
-    Ok(())
 }
 
 fn build_objects(
@@ -126,11 +98,11 @@ fn build_objects(
     let mut objects = Vec::new();
     let format = nasm_format(ctx.platform);
     for source in sources {
-        let obj_path = object_path(obj_dir, source, obj_ext);
+        let obj_path = common::object_path(obj_dir, source, obj_ext);
         if let Some(parent) = Path::new(&obj_path).parent() {
             fs::create_dir_all(parent).map_err(|err| format!("obj dir error: {err}"))?;
         }
-        if needs_rebuild(source, &obj_path) {
+        if common::needs_rebuild(source, &obj_path) {
             let mut cmd = Command::new(assembler);
             cmd.arg("-f")
                 .arg(format)
@@ -186,24 +158,3 @@ fn nasm_format(platform: Option<&str>) -> &'static str {
         "elf64"
     }
 }
-
-fn object_path(obj_dir: &Path, source: &str, obj_ext: &str) -> String {
-    let src_path = Path::new(source);
-    let rel = src_path
-        .strip_prefix("./src")
-        .or_else(|_| src_path.strip_prefix("src"))
-        .unwrap_or(src_path);
-    let mut out = obj_dir.join(rel);
-    out.set_extension(obj_ext.trim_start_matches('.'));
-    out.to_string_lossy().to_string()
-}
-
-fn needs_rebuild(source: &str, object: &str) -> bool {
-    let src_time = fs::metadata(source).and_then(|m| m.modified());
-    let obj_time = fs::metadata(object).and_then(|m| m.modified());
-    match (src_time, obj_time) {
-        (Ok(s), Ok(o)) => s > o,
-        (Ok(_), Err(_)) => true,
-        _ => true,
-    }
-}

src/core/builder/unix_cc.rs

@@ -1,4 +1,5 @@
 use crate::core::builder::BuildContext;
+use crate::core::builder::common;
 use crate::platform;
 use std::fs;
 use std::path::Path;
@@ -12,13 +13,14 @@ pub fn build(ctx: &BuildContext) -> Result<f64, String> {
         ctx.compiler
     };
     let start_time = Instant::now();
-    let sources = collect_sources(ctx.language)?;
+    let extensions = source_extensions(ctx.language);
+    let sources = common::collect_sources(&extensions, ctx.exclude_dirs)?;
     let obj_dir = Path::new("./target").join(ctx.profile).join("obj");
     let objects = build_objects(compiler, &sources, &obj_dir, ctx, "o")?;
 
     if ctx.kind == "staticlib" {
         let lib_path = platform::lib_path(ctx.profile, ctx.project_name, ctx.target_dir);
-        let mut cmd = Command::new("ar");
+        let mut cmd = Command::new(ctx.archiver.unwrap_or("ar"));
         cmd.arg("rcs").arg(&lib_path);
         for obj in &objects {
             cmd.arg(obj);
@@ -33,7 +35,7 @@ pub fn build(ctx: &BuildContext) -> Result<f64, String> {
         }
     }
 
-    let mut cmd = Command::new(compiler);
+    let mut cmd = Command::new(ctx.linker.unwrap_or(compiler));
     if ctx.kind == "sharedlib" {
         if cfg!(target_os = "macos") {
             cmd.arg("-dynamiclib");
@@ -44,12 +46,6 @@ pub fn build(ctx: &BuildContext) -> Result<f64, String> {
     for obj in &objects {
         cmd.arg(obj);
     }
-    for flag in default_flags(ctx.profile) {
-        cmd.arg(flag);
-    }
-    for flag in ctx.cflags {
-        cmd.arg(flag);
-    }
     for dir in ctx.lib_dirs {
         cmd.arg(format!("-L{dir}"));
     }
@@ -76,44 +72,19 @@ pub fn build(ctx: &BuildContext) -> Result<f64, String> {
     }
 }
 
-fn collect_sources(language: &str) -> Result<Vec<String>, String> {
+pub(crate) fn collect_sources(ctx: &BuildContext) -> Result<Vec<String>, String> {
-    let lang = language.to_lowercase();
+    let extensions = source_extensions(ctx.language);
-    let mut sources = Vec::new();
+    common::collect_sources(&extensions, ctx.exclude_dirs)
-    collect_sources_rec("./src", &lang, &mut sources)?;
-    sources.sort();
-    if sources.is_empty() {
-        return Err("No source files found in ./src".to_string());
-    }
-    Ok(sources)
 }
 
-fn collect_sources_rec(dir: &str, lang: &str, out: &mut Vec<String>) -> Result<(), String> {
+fn source_extensions(language: &str) -> Vec<&str> {
-    let entries = fs::read_dir(dir).map_err(|err| format!("src dir error: {err}"))?;
+    let lang = language.to_lowercase();
-    for entry in entries {
+    match lang.as_str() {
-        let entry = entry.map_err(|err| format!("src dir error: {err}"))?;
+        "c" => vec!["c"],
-        let path = entry.path();
+        "c++" | "cpp" | "cxx" => vec!["cpp", "cxx", "cc"],
-        if path.is_dir() {
+        "asm" => vec!["s", "S", "asm"],
-            collect_sources_rec(&path.to_string_lossy(), lang, out)?;
+        _ => vec!["c"],
-            continue;
     }
-        if !path.is_file() {
-            continue;
-        }
-        let ext = path
-            .extension()
-            .and_then(|v| v.to_str())
-            .unwrap_or("")
-            .to_lowercase();
-        let file = path.to_string_lossy().to_string();
-        let allowed = (lang == "c" && ext == "c")
-            || ((lang == "c++" || lang == "cpp" || lang == "cxx")
-                && (ext == "cpp" || ext == "cxx" || ext == "cc"))
-            || (lang == "asm" && (ext == "s" || ext == "asm"));
-        if allowed {
-            out.push(file);
-        }
-    }
-    Ok(())
 }
 
 fn default_flags(profile: &str) -> &'static [&'static str] {
@@ -140,16 +111,19 @@ fn build_objects(
 ) -> Result<Vec<String>, String> {
     let mut objects = Vec::new();
     for source in sources {
-        let obj_path = object_path(obj_dir, source, obj_ext);
+        let obj_path = common::object_path(obj_dir, source, obj_ext);
         if let Some(parent) = Path::new(&obj_path).parent() {
             fs::create_dir_all(parent).map_err(|err| format!("obj dir error: {err}"))?;
         }
-        if needs_rebuild(source, &obj_path) {
+        if common::needs_rebuild(source, &obj_path) {
             let mut cmd = Command::new(compiler);
             cmd.arg("-c").arg(source).arg("-o").arg(&obj_path);
             if ctx.kind == "sharedlib" {
                 cmd.arg("-fPIC");
             }
+            if let Some(flag) = asm_lang_flag(source) {
+                cmd.arg("-x").arg(flag);
+            }
             if let Some(platform) = ctx.platform
                 && !platform.trim().is_empty()
             {
@@ -167,6 +141,8 @@ fn build_objects(
             for dir in ctx.include_dirs {
                 cmd.arg(format!("-I{dir}"));
             }
+            let d_path = Path::new(&obj_path).with_extension("d");
+            cmd.arg("-MMD").arg("-MF").arg(&d_path);
             match cmd.status() {
                 Ok(status) if status.success() => {}
                 Ok(_) => return Err("Build failed".to_string()),
@@ -178,23 +154,11 @@ fn build_objects(
     Ok(objects)
 }
 
-fn object_path(obj_dir: &Path, source: &str, obj_ext: &str) -> String {
+fn asm_lang_flag(source: &str) -> Option<&'static str> {
-    let src_path = Path::new(source);
+    let ext = Path::new(source).extension().and_then(|v| v.to_str())?;
-    let rel = src_path
+    match ext {
-        .strip_prefix("./src")
+        "S" => Some("assembler-with-cpp"),
-        .or_else(|_| src_path.strip_prefix("src"))
+        "s" | "asm" => Some("assembler"),
-        .unwrap_or(src_path);
+        _ => None,
-    let mut out = obj_dir.join(rel);
-    out.set_extension(obj_ext.trim_start_matches('.'));
-    out.to_string_lossy().to_string()
-}
-
-fn needs_rebuild(source: &str, object: &str) -> bool {
-    let src_time = fs::metadata(source).and_then(|m| m.modified());
-    let obj_time = fs::metadata(object).and_then(|m| m.modified());
-    match (src_time, obj_time) {
-        (Ok(s), Ok(o)) => s > o,
-        (Ok(_), Err(_)) => true,
-        _ => true,
     }
 }

src/core/config.rs

@@ -115,7 +115,7 @@ impl Config {
             .and_then(|v| v.as_table())
             .ok_or_else(|| ConfigError::Invalid("missing [build]".into()))?;
 
-        for key in ["language", "standard", "compiler", "kind"] {
+        for key in ["language", "standard", "compiler"] {
             let value = build.get(key).and_then(|v| v.as_str()).unwrap_or("");
             if value.trim().is_empty() {
                 return Err(ConfigError::Invalid(format!("build.{key} is empty")));
@@ -129,12 +129,22 @@ impl Config {
         {
             return Err(ConfigError::Invalid("build.platform is empty".into()));
         }
+        if let Some(toolchain) = self.get("toolchain").and_then(|v| v.as_table()) {
+            for key in ["cc", "cxx", "as", "ar", "ld"] {
+                if let Some(v) = toolchain.get(key)
+                    && !v.as_str().map(|s| !s.trim().is_empty()).unwrap_or(false)
+                {
+                    return Err(ConfigError::Invalid(format!("toolchain.{key} is invalid")));
+                }
+            }
+        }
         if let Some(kind) = build.get("kind").and_then(|v| v.as_str()) {
             let kind = kind.trim();
-            if kind != "bin" && kind != "staticlib" && kind != "sharedlib" {
+            if !kind.is_empty() && kind != "bin" && kind != "staticlib" && kind != "sharedlib" {
                 return Err(ConfigError::Invalid("build.kind is invalid".into()));
             }
         }
+        self.validate_workspace()?;
         Ok(())
     }
 
@@ -150,6 +160,39 @@ impl Config {
     }
 }
 
+impl Config {
+    fn validate_workspace(&self) -> Result<(), ConfigError> {
+        let Some(workspace) = self.get("workspace").and_then(|v| v.as_table()) else {
+            return Ok(());
+        };
+        for (name, value) in workspace {
+            let tbl = value
+                .as_table()
+                .ok_or_else(|| ConfigError::Invalid(format!("workspace.{name} must be a table")))?;
+            let path = tbl.get("path").and_then(|v| v.as_str()).unwrap_or("");
+            if path.trim().is_empty() {
+                return Err(ConfigError::Invalid(format!(
+                    "workspace.{name}.path is empty"
+                )));
+            }
+            if let Some(deps) = tbl.get("deps") {
+                let arr = deps.as_array().ok_or_else(|| {
+                    ConfigError::Invalid(format!("workspace.{name}.deps must be array"))
+                })?;
+                for item in arr {
+                    let s = item.as_str().unwrap_or("");
+                    if s.trim().is_empty() {
+                        return Err(ConfigError::Invalid(format!(
+                            "workspace.{name}.deps contains empty value"
+                        )));
+                    }
+                }
+            }
+        }
+        Ok(())
+    }
+}
+
 fn read_toml(path: &Path) -> Result<Value, ConfigError> {
     let content = fs::read_to_string(path)?;
     Ok(toml::from_str(&content)?)
@@ -213,6 +256,7 @@ fn format_toml(value: &Value) -> Result<String, ConfigError> {
         .get("dependencies")
         .and_then(|v| v.as_table())
         .ok_or_else(|| ConfigError::Invalid("missing [dependencies]".into()))?;
+    let toolchain = root.get("toolchain").and_then(|v| v.as_table());
 
     let name = package.get("name").and_then(|v| v.as_str()).unwrap_or("");
     let version = package
@@ -251,6 +295,24 @@ fn format_toml(value: &Value) -> Result<String, ConfigError> {
     }
     out.push('\n');
 
+    if let Some(toolchain) = toolchain {
+        let mut lines = Vec::new();
+        for key in ["cc", "cxx", "as", "ar", "ld"] {
+            if let Some(value) = toolchain.get(key).and_then(|v| v.as_str())
+                && !value.trim().is_empty()
+            {
+                lines.push(format!("{key} = \"{value}\""));
+            }
+        }
+        if !lines.is_empty() {
+            out.push_str("[toolchain]\n");
+            for line in lines {
+                out.push_str(&format!("{line}\n"));
+            }
+            out.push('\n');
+        }
+    }
+
     out.push_str("[dependencies]\n");
     if !deps.is_empty() {
         let mut keys: Vec<&String> = deps.keys().collect();
@@ -331,3 +393,198 @@ fn set_path(value: &mut Value, path: &[&str], new_value: Value) -> Result<(), Co
         Err(ConfigError::Invalid("empty key".into()))
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::sync::atomic::{AtomicUsize, Ordering};
+
+    static TEST_COUNTER: AtomicUsize = AtomicUsize::new(0);
+
+    fn temp_dir(prefix: &str) -> PathBuf {
+        let n = TEST_COUNTER.fetch_add(1, Ordering::SeqCst);
+        let dir = std::env::temp_dir().join(format!("dcr_cfg_test_{prefix}_{n}"));
+        let _ = fs::remove_dir_all(&dir);
+        fs::create_dir_all(&dir).unwrap();
+        dir
+    }
+
+    fn write_toml_file(dir: &Path, content: &str) -> PathBuf {
+        let path = dir.join("dcr.toml");
+        fs::write(&path, content).unwrap();
+        path
+    }
+
+    fn minimal_valid_toml() -> &'static str {
+        "[package]\nname = \"test\"\nversion = \"0.1.0\"\n\n[build]\nlanguage = \"c\"\nstandard = \"c11\"\ncompiler = \"clang\"\nkind = \"bin\"\n\n[dependencies]\n"
+    }
+
+    #[test]
+    fn open_valid_toml() {
+        let dir = temp_dir("open_valid");
+        let path = write_toml_file(&dir, minimal_valid_toml());
+        let config = Config::open(&path.to_string_lossy());
+        assert!(config.is_ok(), "should open valid toml");
+    }
+
+    #[test]
+    fn open_invalid_toml_syntax() {
+        let dir = temp_dir("open_invalid");
+        let path = write_toml_file(&dir, "this is not [valid toml !!!");
+        let config = Config::open(&path.to_string_lossy());
+        assert!(config.is_err(), "should fail on invalid TOML syntax");
+    }
+
+    #[test]
+    fn open_nonexistent_fails() {
+        let result = Config::open("/tmp/dcr_nonexistent_file_12345.toml");
+        assert!(result.is_err(), "should fail on nonexistent file");
+    }
+
+    #[test]
+    fn validate_missing_package_fails() {
+        let dir = temp_dir("no_package");
+        let path = write_toml_file(
+            &dir,
+            "[build]\nlanguage = \"c\"\nstandard = \"c11\"\ncompiler = \"clang\"\n\n[dependencies]\n",
+        );
+        let result = Config::open(&path.to_string_lossy());
+        assert!(result.is_err(), "missing [package] should fail validation");
+    }
+
+    #[test]
+    fn validate_missing_build_fails() {
+        let dir = temp_dir("no_build");
+        let path = write_toml_file(
+            &dir,
+            "[package]\nname = \"test\"\nversion = \"0.1.0\"\n\n[dependencies]\n",
+        );
+        let result = Config::open(&path.to_string_lossy());
+        assert!(result.is_err(), "missing [build] should fail validation");
+    }
+
+    #[test]
+    fn validate_empty_language_fails() {
+        let dir = temp_dir("empty_lang");
+        let path = write_toml_file(
+            &dir,
+            "[package]\nname = \"test\"\nversion = \"0.1.0\"\n\n[build]\nlanguage = \"\"\nstandard = \"c11\"\ncompiler = \"clang\"\n\n[dependencies]\n",
+        );
+        let result = Config::open(&path.to_string_lossy());
+        assert!(result.is_err(), "empty language should fail validation");
+    }
+
+    #[test]
+    fn validate_unknown_kind_fails() {
+        let dir = temp_dir("bad_kind");
+        let path = write_toml_file(
+            &dir,
+            "[package]\nname = \"test\"\nversion = \"0.1.0\"\n\n[build]\nlanguage = \"c\"\nstandard = \"c11\"\ncompiler = \"clang\"\nkind = \"exe\"\n\n[dependencies]\n",
+        );
+        let result = Config::open(&path.to_string_lossy());
+        assert!(result.is_err(), "unknown kind 'exe' should fail validation");
+    }
+
+    #[test]
+    fn validate_valid_kinds() {
+        for kind in ["bin", "staticlib", "sharedlib"] {
+            let dir = temp_dir(&format!("kind_{kind}"));
+            let content = format!(
+                "[package]\nname = \"test\"\nversion = \"0.1.0\"\n\n[build]\nlanguage = \"c\"\nstandard = \"c11\"\ncompiler = \"clang\"\nkind = \"{kind}\"\n\n[dependencies]\n"
+            );
+            let path = write_toml_file(&dir, &content);
+            let result = Config::open(&path.to_string_lossy());
+            assert!(result.is_ok(), "kind '{kind}' should be valid");
+        }
+    }
+
+    #[test]
+    fn get_values() {
+        let dir = temp_dir("get_values");
+        let path = write_toml_file(&dir, minimal_valid_toml());
+        let config = Config::open(&path.to_string_lossy()).unwrap();
+
+        assert_eq!(
+            config.get("package.name").and_then(|v| v.as_str()),
+            Some("test")
+        );
+        assert_eq!(
+            config.get("build.language").and_then(|v| v.as_str()),
+            Some("c")
+        );
+        assert_eq!(
+            config.get("build.kind").and_then(|v| v.as_str()),
+            Some("bin")
+        );
+        assert!(config.get("nonexistent.key").is_none());
+    }
+
+    #[test]
+    fn set_and_read_back() {
+        let dir = temp_dir("set_value");
+        let path = write_toml_file(&dir, minimal_valid_toml());
+        let mut config = Config::open(&path.to_string_lossy()).unwrap();
+
+        config
+            .set("package.name", Value::String("newname".to_string()))
+            .unwrap();
+        assert_eq!(
+            config.get("package.name").and_then(|v| v.as_str()),
+            Some("newname")
+        );
+
+        // Verify persisted to disk
+        let config2 = Config::open(&path.to_string_lossy()).unwrap();
+        assert_eq!(
+            config2.get("package.name").and_then(|v| v.as_str()),
+            Some("newname")
+        );
+    }
+
+    #[test]
+    fn new_creates_default_config() {
+        let dir = temp_dir("new_default");
+        let path = dir.join("dcr.toml");
+        let config = Config::new(&path.to_string_lossy()).unwrap();
+
+        assert!(path.exists(), "dcr.toml should be created");
+        assert_eq!(
+            config.get("build.language").and_then(|v| v.as_str()),
+            Some("c")
+        );
+        assert_eq!(
+            config.get("build.standard").and_then(|v| v.as_str()),
+            Some("c11")
+        );
+        assert_eq!(
+            config.get("build.compiler").and_then(|v| v.as_str()),
+            Some("clang")
+        );
+        assert_eq!(
+            config.get("build.kind").and_then(|v| v.as_str()),
+            Some("bin")
+        );
+    }
+
+    #[test]
+    fn validate_workspace_empty_path_fails() {
+        let dir = temp_dir("ws_empty_path");
+        let path = write_toml_file(
+            &dir,
+            "[package]\nname = \"test\"\nversion = \"0.1.0\"\n\n[build]\nlanguage = \"c\"\nstandard = \"c11\"\ncompiler = \"clang\"\n\n[workspace]\n[workspace.member1]\npath = \"\"\n\n[dependencies]\n",
+        );
+        let result = Config::open(&path.to_string_lossy());
+        assert!(
+            result.is_err(),
+            "workspace member with empty path should fail"
+        );
+    }
+
+    #[test]
+    fn check_returns_bool() {
+        let dir = temp_dir("check_bool");
+        let path = write_toml_file(&dir, minimal_valid_toml());
+        let config = Config::open(&path.to_string_lossy()).unwrap();
+        assert!(config.check(), "valid config should return true");
+    }
+}

src/core/mod.rs

@@ -2,3 +2,4 @@ pub mod builder;
 pub mod config;
 pub mod deps;
 pub mod runner;
+pub mod workspace;

src/core/workspace.rs

@@ -0,0 +1,124 @@
+use crate::core::config::Config;
+use std::collections::{HashMap, HashSet};
+use std::path::{Path, PathBuf};
+use toml::Value;
+
+#[derive(Debug, Clone)]
+pub struct WorkspaceMember {
+    pub name: String,
+    pub path: PathBuf,
+    pub deps: Vec<String>,
+}
+
+#[derive(Debug, Clone)]
+pub struct Workspace {
+    pub members: Vec<WorkspaceMember>,
+}
+
+pub fn parse_workspace(config: &Config, root: &Path) -> Result<Option<Workspace>, String> {
+    let table = match config.get("workspace").and_then(|v| v.as_table()) {
+        Some(t) => t,
+        None => return Ok(None),
+    };
+
+    let mut members = Vec::new();
+    for (name, value) in table {
+        let tbl = value
+            .as_table()
+            .ok_or_else(|| format!("workspace.{name} must be a table with path and deps"))?;
+        let path_raw = tbl
+            .get("path")
+            .and_then(|v| v.as_str())
+            .ok_or_else(|| format!("workspace.{name}.path is required"))?;
+        let path = resolve_path(root, path_raw)?;
+        if !path.join("dcr.toml").is_file() {
+            return Err(format!(
+                "workspace.{name}.path does not contain dcr.toml: {}",
+                path.display()
+            ));
+        }
+        let deps = parse_deps(tbl.get("deps"))?;
+        members.push(WorkspaceMember {
+            name: name.to_string(),
+            path,
+            deps,
+        });
+    }
+
+    let mut ws = Workspace { members };
+    ws.members = topo_sort(&ws.members)?;
+    Ok(Some(ws))
+}
+
+fn resolve_path(root: &Path, raw: &str) -> Result<PathBuf, String> {
+    let p = Path::new(raw);
+    let full = if p.is_absolute() {
+        p.to_path_buf()
+    } else {
+        root.join(p)
+    };
+    Ok(full)
+}
+
+fn parse_deps(value: Option<&Value>) -> Result<Vec<String>, String> {
+    let Some(value) = value else {
+        return Ok(Vec::new());
+    };
+    let arr = value
+        .as_array()
+        .ok_or_else(|| "workspace deps must be an array of strings".to_string())?;
+    let mut out = Vec::new();
+    for item in arr {
+        let s = item
+            .as_str()
+            .ok_or_else(|| "workspace deps must be an array of strings".to_string())?;
+        out.push(s.to_string());
+    }
+    Ok(out)
+}
+
+fn topo_sort(members: &[WorkspaceMember]) -> Result<Vec<WorkspaceMember>, String> {
+    let mut map = HashMap::new();
+    for m in members {
+        map.insert(m.name.clone(), m.clone());
+    }
+    let mut state: HashMap<String, u8> = HashMap::new();
+    let mut order: Vec<WorkspaceMember> = Vec::new();
+
+    for name in map.keys() {
+        if *state.get(name).unwrap_or(&0) == 0 {
+            visit(name, &map, &mut state, &mut order)?;
+        }
+    }
+    Ok(order)
+}
+
+fn visit(
+    name: &str,
+    map: &HashMap<String, WorkspaceMember>,
+    state: &mut HashMap<String, u8>,
+    order: &mut Vec<WorkspaceMember>,
+) -> Result<(), String> {
+    match state.get(name).copied().unwrap_or(0) {
+        1 => return Err(format!("workspace dependency cycle at {name}")),
+        2 => return Ok(()),
+        _ => {}
+    }
+    state.insert(name.to_string(), 1);
+    let member = map
+        .get(name)
+        .ok_or_else(|| format!("unknown workspace member {name}"))?;
+    let mut seen = HashSet::new();
+    for dep in &member.deps {
+        if !seen.insert(dep) {
+            continue;
+        }
+        if !map.contains_key(dep) {
+            return Err(format!("workspace dependency '{dep}' not found"));
+        }
+        visit(dep, map, state, order)?;
+    }
+    state.insert(name.to_string(), 2);
+    order.push(member.clone());
+    Ok(())
+}

src/platform/linux.rs

@@ -18,3 +18,57 @@ pub fn shared_lib_path(profile: &str, name: &str, target_dir: Option<&str>) -> S
         None => format!("./target/{profile}/lib{name}.so"),
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn bin_path_default() {
+        assert_eq!(bin_path("debug", "hello", None), "./target/debug/hello");
+    }
+
+    #[test]
+    fn bin_path_release() {
+        assert_eq!(bin_path("release", "hello", None), "./target/release/hello");
+    }
+
+    #[test]
+    fn bin_path_custom_target() {
+        assert_eq!(bin_path("debug", "hello", Some("out")), "out/hello");
+    }
+
+    #[test]
+    fn bin_path_custom_target_trailing_slash() {
+        assert_eq!(bin_path("debug", "hello", Some("out/")), "out/hello");
+    }
+
+    #[test]
+    fn lib_path_default() {
+        assert_eq!(
+            lib_path("debug", "mylib", None),
+            "./target/debug/libmylib.a"
+        );
+    }
+
+    #[test]
+    fn lib_path_custom_target() {
+        assert_eq!(lib_path("debug", "mylib", Some("out")), "out/libmylib.a");
+    }
+
+    #[test]
+    fn shared_lib_path_default() {
+        assert_eq!(
+            shared_lib_path("debug", "mylib", None),
+            "./target/debug/libmylib.so"
+        );
+    }
+
+    #[test]
+    fn shared_lib_path_custom_target() {
+        assert_eq!(
+            shared_lib_path("release", "mylib", Some("dist")),
+            "dist/libmylib.so"
+        );
+    }
+}

src/utils/fs.rs

@@ -1,5 +1,5 @@
 use std::io;
-use std::path::PathBuf;
+use std::path::{Path, PathBuf};
 
 #[allow(dead_code)]
 pub fn check_dir(dir: Option<&str>) -> io::Result<Vec<String>> {
@@ -16,3 +16,16 @@ pub fn check_dir(dir: Option<&str>) -> io::Result<Vec<String>> {
 
     Ok(items)
 }
+
+pub fn find_project_root(start: &Path) -> io::Result<Option<PathBuf>> {
+    let mut current = start.to_path_buf();
+    loop {
+        if current.join("dcr.toml").is_file() {
+            return Ok(Some(current));
+        }
+        if !current.pop() {
+            break;
+        }
+    }
+    Ok(None)
+}

tests/cli_basic.rs

@@ -19,25 +19,32 @@ fn bin_path() -> PathBuf {
     path
 }
 
-fn unique_temp_dir(prefix: &str) -> PathBuf {
+fn unique_sandbox_dir(prefix: &str) -> PathBuf {
     let pid = std::process::id();
     let n = COUNTER.fetch_add(1, Ordering::SeqCst);
     let now = SystemTime::now()
         .duration_since(UNIX_EPOCH)
         .unwrap_or_default()
         .as_nanos();
-    let mut path = std::env::temp_dir();
+    let mut path = PathBuf::from(env!("CARGO_MANIFEST_DIR"));
+    path.push("sandbox");
+    path.push("cli-tests");
     path.push(format!("dcr_{prefix}_{pid}_{n}_{now}"));
     std::fs::create_dir_all(&path).expect("failed to create temp dir");
     path
 }
 
 fn run_dcr(args: &[&str], cwd: &Path) -> std::process::Output {
-    Command::new(bin_path())
+    run_dcr_env(args, cwd, &[])
-        .args(args)
+}
-        .current_dir(cwd)
+
-        .output()
+fn run_dcr_env(args: &[&str], cwd: &Path, envs: &[(&str, &str)]) -> std::process::Output {
-        .expect("failed to run dcr")
+    let mut cmd = Command::new(bin_path());
+    cmd.args(args).current_dir(cwd);
+    for (k, v) in envs {
+        cmd.env(k, v);
+    }
+    cmd.output().expect("failed to run dcr")
 }
 
 fn ensure_bin_built() {
@@ -51,9 +58,23 @@ fn ensure_bin_built() {
     });
 }
 
+fn available_compiler() -> Option<&'static str> {
+    for candidate in ["clang", "gcc", "cc"] {
+        let ok = Command::new(candidate)
+            .arg("--version")
+            .output()
+            .map(|o| o.status.success())
+            .unwrap_or(false);
+        if ok {
+            return Some(candidate);
+        }
+    }
+    None
+}
+
 #[test]
 fn help_and_version_work() {
-    let dir = unique_temp_dir("help");
+    let dir = unique_sandbox_dir("help");
     let out = run_dcr(&["--help"], &dir);
     assert!(out.status.success(), "--help should succeed");
 
@@ -65,7 +86,7 @@ fn help_and_version_work() {
 
 #[test]
 fn new_creates_project_layout() {
-    let dir = unique_temp_dir("new");
+    let dir = unique_sandbox_dir("new");
     let out = run_dcr(&["new", "hello"], &dir);
     assert!(out.status.success(), "dcr new should succeed");
 
@@ -80,7 +101,7 @@ fn new_creates_project_layout() {
 
 #[test]
 fn init_and_clean_remove_target() {
-    let dir = unique_temp_dir("init");
+    let dir = unique_sandbox_dir("init");
     let out = run_dcr(&["init"], &dir);
     assert!(out.status.success(), "dcr init should succeed");
 
@@ -92,3 +113,108 @@ fn init_and_clean_remove_target() {
     assert!(out.status.success(), "dcr clean should succeed");
     assert!(!dir.join("target").exists(), "target should be removed");
 }
+
+#[test]
+fn build_run_clean_flags_normal_project() {
+    let Some(compiler) = available_compiler() else {
+        eprintln!("no compiler found; skipping build/run test");
+        return;
+    };
+
+    let dir = unique_sandbox_dir("normal");
+    let out = run_dcr(&["init"], &dir);
+    assert!(out.status.success(), "dcr init should succeed");
+
+    let envs = [("DCR_COMPILER", compiler)];
+    let out = run_dcr_env(&["build"], &dir, &envs);
+    assert!(out.status.success(), "dcr build should succeed");
+
+    let out = run_dcr_env(&["build", "--release"], &dir, &envs);
+    assert!(out.status.success(), "dcr build --release should succeed");
+
+    let out = run_dcr_env(&["run"], &dir, &envs);
+    assert!(out.status.success(), "dcr run should succeed");
+    let stdout = String::from_utf8_lossy(&out.stdout);
+    assert!(stdout.contains("Hello World!"), "run output missing");
+
+    let out = run_dcr_env(&["clean", "--release"], &dir, &envs);
+    assert!(out.status.success(), "dcr clean --release should succeed");
+    assert!(
+        !dir.join("target").join("release").exists(),
+        "target/release should be removed"
+    );
+    assert!(
+        dir.join("target").join("debug").is_dir(),
+        "target/debug should remain"
+    );
+
+    let out = run_dcr_env(&["clean"], &dir, &envs);
+    assert!(out.status.success(), "dcr clean should succeed");
+    assert!(!dir.join("target").exists(), "target should be removed");
+}
+
+#[test]
+fn workspace_build_and_clean_all() {
+    let Some(compiler) = available_compiler() else {
+        eprintln!("no compiler found; skipping workspace test");
+        return;
+    };
+
+    let root = unique_sandbox_dir("workspace");
+    let out = run_dcr(&["init"], &root);
+    assert!(out.status.success(), "root init should succeed");
+
+    let members = [
+        ("userspace", &[][..]),
+        ("core", &["userspace"][..]),
+        ("kernel", &["core"][..]),
+    ];
+    for (name, _) in &members {
+        let member_dir = root.join("src").join(name);
+        std::fs::create_dir_all(&member_dir).expect("failed to create member dir");
+        let out = run_dcr(&["init"], &member_dir);
+        assert!(out.status.success(), "member init should succeed");
+    }
+
+    let workspace_toml = "[package]\nname = \"ws-root\"\nversion = \"0.1.0\"\n\n[build]\nlanguage = \"c\"\nstandard = \"c11\"\ncompiler = \"clang\"\nkind = \"bin\"\n\n[workspace]\nuserspace = { path = \"src/userspace\", deps = [] }\ncore = { path = \"src/core\", deps = [\"userspace\"] }\nkernel = { path = \"src/kernel\", deps = [\"core\"] }\n\n[dependencies]\n";
+    std::fs::write(root.join("dcr.toml"), workspace_toml).expect("failed to write root dcr.toml");
+
+    let envs = [("DCR_COMPILER", compiler)];
+    let out = run_dcr_env(&["build"], &root, &envs);
+    assert!(out.status.success(), "workspace build should succeed");
+
+    let out = run_dcr_env(&["build"], &root, &envs);
+    assert!(out.status.success(), "workspace build should succeed");
+
+    let out = run_dcr_env(&["build", "--release"], &root, &envs);
+    assert!(
+        out.status.success(),
+        "workspace build --release should succeed"
+    );
+
+    let out = run_dcr_env(&["clean", "--release", "--all"], &root, &envs);
+    assert!(
+        out.status.success(),
+        "workspace clean --all --release should succeed"
+    );
+
+    for (name, _) in &members {
+        let member = root.join("src").join(name);
+        assert!(
+            !member.join("target").join("release").exists(),
+            "member target/release should be removed"
+        );
+        assert!(
+            member.join("target").join("debug").exists(),
+            "member target/debug should remain"
+        );
+    }
+    assert!(
+        !root.join("target").join("release").exists(),
+        "root target/release should be removed"
+    );
+    assert!(
+        root.join("target").join("debug").exists(),
+        "root target/debug should remain"
+    );
+}

tests/cli_errors.rs

@@ -0,0 +1,297 @@
+use std::path::{Path, PathBuf};
+use std::process::Command;
+use std::sync::Once;
+use std::sync::atomic::{AtomicUsize, Ordering};
+use std::time::{SystemTime, UNIX_EPOCH};
+
+static COUNTER: AtomicUsize = AtomicUsize::new(0);
+static BUILD_ONCE: Once = Once::new();
+
+fn bin_path() -> PathBuf {
+    if let Ok(exe) = std::env::var("CARGO_BIN_EXE_dcr") {
+        return PathBuf::from(exe);
+    }
+    ensure_bin_built();
+    let mut path = PathBuf::from(env!("CARGO_MANIFEST_DIR"));
+    path.push("target");
+    path.push("debug");
+    path.push(format!("dcr{}", std::env::consts::EXE_SUFFIX));
+    path
+}
+
+fn unique_sandbox_dir(prefix: &str) -> PathBuf {
+    let pid = std::process::id();
+    let n = COUNTER.fetch_add(1, Ordering::SeqCst);
+    let now = SystemTime::now()
+        .duration_since(UNIX_EPOCH)
+        .unwrap_or_default()
+        .as_nanos();
+    let mut path = PathBuf::from(env!("CARGO_MANIFEST_DIR"));
+    path.push("sandbox");
+    path.push("cli-tests");
+    path.push(format!("dcr_{prefix}_{pid}_{n}_{now}"));
+    std::fs::create_dir_all(&path).expect("failed to create temp dir");
+    path
+}
+
+fn run_dcr(args: &[&str], cwd: &Path) -> std::process::Output {
+    let mut cmd = Command::new(bin_path());
+    cmd.args(args).current_dir(cwd);
+    cmd.output().expect("failed to run dcr")
+}
+
+fn run_dcr_env(args: &[&str], cwd: &Path, envs: &[(&str, &str)]) -> std::process::Output {
+    let mut cmd = Command::new(bin_path());
+    cmd.args(args).current_dir(cwd);
+    for (k, v) in envs {
+        cmd.env(k, v);
+    }
+    cmd.output().expect("failed to run dcr")
+}
+
+fn ensure_bin_built() {
+    BUILD_ONCE.call_once(|| {
+        let status = Command::new("cargo")
+            .arg("build")
+            .current_dir(env!("CARGO_MANIFEST_DIR"))
+            .status()
+            .expect("failed to run cargo build");
+        assert!(status.success(), "cargo build failed");
+    });
+}
+
+fn available_compiler() -> Option<&'static str> {
+    for candidate in ["clang", "gcc", "cc"] {
+        let ok = Command::new(candidate)
+            .arg("--version")
+            .output()
+            .map(|o| o.status.success())
+            .unwrap_or(false);
+        if ok {
+            return Some(candidate);
+        }
+    }
+    None
+}
+
+// --- Tests ---
+
+#[test]
+fn no_args_shows_help() {
+    let dir = unique_sandbox_dir("noargs");
+    let out = run_dcr(&[], &dir);
+    // Should succeed (help returns 0) and produce some output
+    let stdout = String::from_utf8_lossy(&out.stdout);
+    assert!(
+        stdout.contains("DCR") || stdout.contains("dcr") || stdout.contains("USAGE"),
+        "no args should show help text"
+    );
+}
+
+#[test]
+fn unknown_command_fails() {
+    let dir = unique_sandbox_dir("unknown_cmd");
+    let out = run_dcr(&["foobar"], &dir);
+    let stdout = String::from_utf8_lossy(&out.stdout);
+    assert!(
+        stdout.contains("error") || stdout.contains("Unknown"),
+        "unknown command should print error"
+    );
+}
+
+#[test]
+fn build_without_toml_fails() {
+    let dir = unique_sandbox_dir("build_no_toml");
+    let out = run_dcr(&["build"], &dir);
+    assert!(!out.status.success(), "build without dcr.toml should fail");
+    let stdout = String::from_utf8_lossy(&out.stdout);
+    assert!(
+        stdout.contains("dcr.toml") || stdout.contains("not found"),
+        "should mention missing dcr.toml"
+    );
+}
+
+#[test]
+fn run_without_toml_fails() {
+    let dir = unique_sandbox_dir("run_no_toml");
+    let out = run_dcr(&["run"], &dir);
+    assert!(!out.status.success(), "run without dcr.toml should fail");
+}
+
+#[test]
+fn clean_without_toml_fails() {
+    let dir = unique_sandbox_dir("clean_no_toml");
+    let out = run_dcr(&["clean"], &dir);
+    assert!(!out.status.success(), "clean without dcr.toml should fail");
+}
+
+#[test]
+fn new_existing_dir_fails() {
+    let dir = unique_sandbox_dir("new_exist");
+    // Create the project directory first
+    std::fs::create_dir_all(dir.join("hello")).expect("failed to create dir");
+    let out = run_dcr(&["new", "hello"], &dir);
+    assert!(!out.status.success(), "dcr new on existing dir should fail");
+    let stdout = String::from_utf8_lossy(&out.stdout);
+    assert!(
+        stdout.contains("already exists") || stdout.contains("error"),
+        "should report dir already exists"
+    );
+}
+
+#[test]
+fn init_nonempty_dir_fails() {
+    let dir = unique_sandbox_dir("init_nonempty");
+    // Put a file in the dir so it's not empty
+    std::fs::write(dir.join("dummy.txt"), "x").expect("failed to write");
+    let out = run_dcr(&["init"], &dir);
+    assert!(
+        !out.status.success(),
+        "dcr init in non-empty dir should fail"
+    );
+    let stdout = String::from_utf8_lossy(&out.stdout);
+    assert!(
+        stdout.contains("not empty") || stdout.contains("error"),
+        "should report dir not empty"
+    );
+}
+
+#[test]
+fn build_unknown_flag_fails() {
+    let dir = unique_sandbox_dir("build_badflag");
+    // Init a valid project first
+    let out = run_dcr(&["init"], &dir);
+    assert!(out.status.success(), "init should succeed");
+    let out = run_dcr(&["build", "--foobar"], &dir);
+    assert!(!out.status.success(), "build with unknown flag should fail");
+}
+
+#[test]
+fn run_library_project_fails() {
+    let Some(compiler) = available_compiler() else {
+        eprintln!("no compiler found; skipping run_library test");
+        return;
+    };
+
+    let dir = unique_sandbox_dir("run_lib");
+    let out = run_dcr(&["init"], &dir);
+    assert!(out.status.success(), "init should succeed");
+
+    // Edit dcr.toml to set kind = "staticlib"
+    let toml_path = dir.join("dcr.toml");
+    let toml = std::fs::read_to_string(&toml_path).expect("failed to read dcr.toml");
+    let updated = toml.replace("kind = \"bin\"", "kind = \"staticlib\"");
+    std::fs::write(&toml_path, updated).expect("failed to write dcr.toml");
+
+    let envs = [("DCR_COMPILER", compiler)];
+    let out = run_dcr_env(&["run"], &dir, &envs);
+    assert!(!out.status.success(), "dcr run on staticlib should fail");
+    let stdout = String::from_utf8_lossy(&out.stdout);
+    assert!(
+        stdout.contains("library") || stdout.contains("Cannot run"),
+        "should report cannot run library"
+    );
+}
+
+#[test]
+fn clean_specific_profile() {
+    let dir = unique_sandbox_dir("clean_profile");
+    let out = run_dcr(&["init"], &dir);
+    assert!(out.status.success(), "init should succeed");
+
+    // Create target/debug and target/release dirs
+    std::fs::create_dir_all(dir.join("target").join("debug")).expect("create debug");
+    std::fs::write(dir.join("target").join("debug").join("dummy.o"), "x").expect("write");
+    std::fs::create_dir_all(dir.join("target").join("release")).expect("create release");
+    std::fs::write(dir.join("target").join("release").join("dummy.o"), "x").expect("write");
+
+    // Clean only release
+    let out = run_dcr(&["clean", "--release"], &dir);
+    assert!(out.status.success(), "clean --release should succeed");
+    assert!(
+        !dir.join("target").join("release").exists(),
+        "target/release should be removed"
+    );
+    assert!(
+        dir.join("target").join("debug").is_dir(),
+        "target/debug should remain"
+    );
+}
+
+#[test]
+fn new_no_name_fails() {
+    let dir = unique_sandbox_dir("new_noname");
+    let out = run_dcr(&["new"], &dir);
+    assert!(!out.status.success(), "dcr new without name should fail");
+    let stdout = String::from_utf8_lossy(&out.stdout);
+    assert!(
+        stdout.contains("not specified") || stdout.contains("error"),
+        "should report name not specified"
+    );
+}
+
+#[test]
+fn staticlib_build() {
+    let Some(compiler) = available_compiler() else {
+        eprintln!("no compiler found; skipping staticlib test");
+        return;
+    };
+    let dir = unique_sandbox_dir("staticlib");
+    let out = run_dcr(&["init"], &dir);
+    assert!(out.status.success(), "init should succeed");
+
+    let toml_path = dir.join("dcr.toml");
+    let toml = std::fs::read_to_string(&toml_path).expect("read dcr.toml");
+    let updated = toml.replace("kind = \"bin\"", "kind = \"staticlib\"");
+    std::fs::write(&toml_path, updated).expect("write dcr.toml");
+
+    let envs = [("DCR_COMPILER", compiler)];
+    let out = run_dcr_env(&["build"], &dir, &envs);
+    assert!(out.status.success(), "staticlib build should succeed");
+    // Check that a .a file exists
+    let lib_path = dir.join("target").join("debug");
+    let has_lib = std::fs::read_dir(&lib_path)
+        .map(|entries| {
+            entries
+                .filter_map(|e| e.ok())
+                .any(|e| e.file_name().to_string_lossy().ends_with(".a"))
+        })
+        .unwrap_or(false);
+    assert!(has_lib, "staticlib should produce a .a file");
+}
+
+#[test]
+fn build_release_profile() {
+    let Some(compiler) = available_compiler() else {
+        eprintln!("no compiler found; skipping release build test");
+        return;
+    };
+    let dir = unique_sandbox_dir("release_build");
+    let out = run_dcr(&["init"], &dir);
+    assert!(out.status.success(), "init should succeed");
+
+    let envs = [("DCR_COMPILER", compiler)];
+    let out = run_dcr_env(&["build", "--release"], &dir, &envs);
+    assert!(out.status.success(), "release build should succeed");
+    assert!(
+        dir.join("target").join("release").is_dir(),
+        "target/release should exist"
+    );
+}
+
+#[test]
+fn version_contains_version_string() {
+    let dir = unique_sandbox_dir("version");
+    let out = run_dcr(&["--version"], &dir);
+    assert!(out.status.success());
+    let stdout = String::from_utf8_lossy(&out.stdout);
+    // Should contain version like "dcr 0.2.8 (target)"
+    assert!(
+        stdout.contains("dcr "),
+        "version output should start with 'dcr '"
+    );
+    assert!(
+        stdout.contains('.'),
+        "version output should contain a version number"
+    );
+}