[M1] add cargoxx new

CHANGELOG.md

@@ -36,3 +36,10 @@ All notable changes to cargoxx will be documented in this file.
   sorts results for deterministic output, and returns `LayoutNoTarget`
   when neither a library nor any binary is present.
   `tests/layout_discovery.cpp` covers 12 cases.
+- `cargoxx new <name>` and `cargoxx new --lib <name>` scaffold a project
+  directory with `Cargoxx.toml`, `src/main.cpp` or `src/lib.cppm`, and a
+  minimal `.gitignore`. Hyphens in the package name are mapped to
+  underscores when generating the module/namespace identifier.
+  Codegen of `flake.nix` / `CMakeLists.txt` is intentionally deferred to M3.
+  CLI11 v2.6.2 vendored at `third_party/CLI11.hpp`; entry point is now
+  `cargoxx::cli::run(argc, argv)`. `tests/cmd_new.cpp` covers 9 cases.

CMakeLists.txt

@@ -38,6 +38,8 @@ target_sources(cargoxx
         src/manifest/parser.cpp
         src/manifest/writer.cpp
         src/layout/layout.cpp
+        src/cli/cmd_new.cpp
+        src/cli/run.cpp
     PUBLIC
         FILE_SET CXX_MODULES FILES
             src/lib.cppm

src/cli/cli.cppm

@@ -1,10 +1,14 @@
 export module cargoxx.cli;
 
+import std;
 import cargoxx.util;
-import cargoxx.exec;
 import cargoxx.manifest;
-import cargoxx.lockfile;
-import cargoxx.layout;
-import cargoxx.linkdb;
-import cargoxx.resolver;
-import cargoxx.codegen;
+
+export namespace cargoxx::cli {
+
+auto cmd_new(const std::string& name, bool lib_only,
+             const std::filesystem::path& parent_dir) -> util::Result<void>;
+
+auto run(int argc, char** argv) -> int;
+
+} // namespace cargoxx::cli

src/cli/cmd_new.cpp

@@ -0,0 +1,158 @@
+module cargoxx.cli;
+
+import std;
+import cargoxx.util;
+import cargoxx.manifest;
+
+namespace cargoxx::cli {
+
+namespace {
+
+constexpr std::string_view MAIN_CPP_TEMPLATE = R"(import std;
+
+int main() {
+    std::println("Hello from {}!", "@@NAME@@");
+    return 0;
+}
+)";
+
+constexpr std::string_view LIB_CPPM_TEMPLATE = R"(export module @@MODULE@@;
+
+import std;
+
+export namespace @@MODULE@@ {
+    auto greeting() -> std::string_view {
+        return "Hello from @@NAME@@!";
+    }
+}
+)";
+
+constexpr std::string_view GITIGNORE_TEMPLATE = "/build/\n";
+
+auto is_valid_pkg_name(std::string_view s) -> bool {
+    if (s.empty() || std::isdigit(static_cast<unsigned char>(s[0]))) {
+        return false;
+    }
+    for (char c : s) {
+        bool ok = std::isalnum(static_cast<unsigned char>(c)) || c == '_' || c == '-';
+        if (!ok) {
+            return false;
+        }
+    }
+    return true;
+}
+
+auto sanitize_id(std::string_view s) -> std::string {
+    std::string out{s};
+    std::ranges::replace(out, '-', '_');
+    return out;
+}
+
+auto substitute(std::string_view tmpl, std::string_view marker, std::string_view value)
+    -> std::string {
+    std::string out;
+    out.reserve(tmpl.size());
+    std::size_t pos = 0;
+    while (pos < tmpl.size()) {
+        auto next = tmpl.find(marker, pos);
+        if (next == std::string_view::npos) {
+            out.append(tmpl.substr(pos));
+            break;
+        }
+        out.append(tmpl.substr(pos, next - pos));
+        out.append(value);
+        pos = next + marker.size();
+    }
+    return out;
+}
+
+auto write_text(const std::filesystem::path& path, std::string_view content)
+    -> util::Result<void> {
+    std::ofstream out{path};
+    if (!out) {
+        return std::unexpected(util::Error{
+            util::ErrorCode::Internal,
+            std::format("cannot open for writing: {}", path.string()),
+            "", path, std::nullopt,
+        });
+    }
+    out << content;
+    if (!out) {
+        return std::unexpected(util::Error{
+            util::ErrorCode::Internal,
+            std::format("write failed: {}", path.string()),
+            "", path, std::nullopt,
+        });
+    }
+    return {};
+}
+
+} // namespace
+
+auto cmd_new(const std::string& name, bool lib_only,
+             const std::filesystem::path& parent_dir) -> util::Result<void> {
+    if (!is_valid_pkg_name(name)) {
+        return std::unexpected(util::Error{
+            util::ErrorCode::LayoutInvalidName,
+            std::format("invalid package name '{}'", name),
+            "names must match [a-zA-Z_][a-zA-Z0-9_-]*",
+            std::nullopt, std::nullopt,
+        });
+    }
+
+    const auto root = parent_dir / name;
+    std::error_code ec;
+    if (std::filesystem::exists(root, ec)) {
+        return std::unexpected(util::Error{
+            util::ErrorCode::Internal,
+            std::format("destination '{}' already exists", root.string()),
+            "remove it or pick a different name",
+            root, std::nullopt,
+        });
+    }
+
+    std::filesystem::create_directories(root / "src", ec);
+    if (ec) {
+        return std::unexpected(util::Error{
+            util::ErrorCode::Internal,
+            std::format("cannot create '{}': {}", (root / "src").string(), ec.message()),
+            "", root / "src", std::nullopt,
+        });
+    }
+
+    manifest::Manifest m{
+        .package = manifest::Package{
+            .name = name,
+            .version = "0.1.0",
+            .edition = manifest::Edition::Cpp23,
+            .authors = {},
+            .license = std::nullopt,
+        },
+        .dependencies = {},
+        .build = {},
+    };
+    if (auto r = manifest::write(m, root / "Cargoxx.toml"); !r) {
+        return std::unexpected(r.error());
+    }
+
+    if (lib_only) {
+        auto content = substitute(LIB_CPPM_TEMPLATE, "@@MODULE@@", sanitize_id(name));
+        content = substitute(content, "@@NAME@@", name);
+        if (auto r = write_text(root / "src" / "lib.cppm", content); !r) {
+            return std::unexpected(r.error());
+        }
+    } else {
+        auto content = substitute(MAIN_CPP_TEMPLATE, "@@NAME@@", name);
+        if (auto r = write_text(root / "src" / "main.cpp", content); !r) {
+            return std::unexpected(r.error());
+        }
+    }
+
+    if (auto r = write_text(root / ".gitignore", GITIGNORE_TEMPLATE); !r) {
+        return std::unexpected(r.error());
+    }
+
+    return {};
+}
+
+} // namespace cargoxx::cli

src/cli/run.cpp

@@ -0,0 +1,48 @@
+module;
+
+#include <CLI11.hpp>
+
+module cargoxx.cli;
+
+import std;
+import cargoxx.util;
+
+namespace cargoxx::cli {
+
+auto run(int argc, char** argv) -> int {
+    CLI::App app{"cargoxx — a Cargo-style project tool for modern C++"};
+    app.require_subcommand(1);
+
+    auto* new_cmd = app.add_subcommand("new", "Create a new cargoxx project");
+    std::string new_name;
+    bool new_lib = false;
+    new_cmd->add_option("name", new_name, "Project name")->required();
+    new_cmd->add_flag("--lib", new_lib, "Create a library project");
+
+    try {
+        app.parse(argc, argv);
+    } catch (const CLI::ParseError& e) {
+        return app.exit(e);
+    }
+
+    if (*new_cmd) {
+        std::error_code ec;
+        auto cwd = std::filesystem::current_path(ec);
+        if (ec) {
+            std::cerr << std::format("error: cannot determine current working directory: {}\n",
+                                     ec.message());
+            return 1;
+        }
+        auto r = cmd_new(new_name, new_lib, cwd);
+        if (!r) {
+            std::cerr << util::format(r.error());
+            return 1;
+        }
+        std::cout << std::format("    Created `{}` project\n", new_name);
+        return 0;
+    }
+
+    return 0;
+}
+
+} // namespace cargoxx::cli

src/main.cpp

@@ -1,7 +1,5 @@
-import cargoxx;
-import std;
+import cargoxx.cli;
 
-int main(int /*argc*/, char** /*argv*/) {
-    std::println("Hello, cargoxx!");
-    return 0;
+int main(int argc, char** argv) {
+    return cargoxx::cli::run(argc, argv);
 }

tests/CMakeLists.txt

@@ -11,3 +11,4 @@ cargoxx_add_test(util_error)
 cargoxx_add_test(manifest_parse)
 cargoxx_add_test(manifest_write)
 cargoxx_add_test(layout_discovery)
+cargoxx_add_test(cmd_new)

tests/cmd_new.cpp

@@ -0,0 +1,110 @@
+#include <catch2/catch_test_macros.hpp>
+
+import cargoxx.cli;
+import cargoxx.manifest;
+import cargoxx.util;
+import std;
+
+using cargoxx::cli::cmd_new;
+using cargoxx::util::ErrorCode;
+namespace manifest = cargoxx::manifest;
+
+namespace {
+
+auto fresh_dir() -> std::filesystem::path {
+    auto d = std::filesystem::temp_directory_path() /
+             std::format("cargoxx-cmd_new-test-{}", std::random_device{}());
+    std::filesystem::create_directories(d);
+    return d;
+}
+
+auto read_file(const std::filesystem::path& p) -> std::string {
+    std::ifstream in{p};
+    return std::string{std::istreambuf_iterator<char>(in), {}};
+}
+
+} // namespace
+
+TEST_CASE("cmd_new --bin scaffolds a binary project", "[cli][new]") {
+    auto parent = fresh_dir();
+    REQUIRE(cmd_new("hello", false, parent).has_value());
+
+    auto root = parent / "hello";
+    REQUIRE(std::filesystem::exists(root / "Cargoxx.toml"));
+    REQUIRE(std::filesystem::exists(root / "src" / "main.cpp"));
+    REQUIRE_FALSE(std::filesystem::exists(root / "src" / "lib.cppm"));
+    REQUIRE(std::filesystem::exists(root / ".gitignore"));
+
+    auto m = manifest::parse(root / "Cargoxx.toml");
+    REQUIRE(m.has_value());
+    REQUIRE(m->package.name == "hello");
+    REQUIRE(m->package.version == "0.1.0");
+    REQUIRE(m->package.edition == manifest::Edition::Cpp23);
+
+    auto main_src = read_file(root / "src" / "main.cpp");
+    REQUIRE(main_src.find("import std;") != std::string::npos);
+    REQUIRE(main_src.find("\"hello\"") != std::string::npos);
+}
+
+TEST_CASE("cmd_new --lib scaffolds a library project", "[cli][new]") {
+    auto parent = fresh_dir();
+    REQUIRE(cmd_new("widget", true, parent).has_value());
+
+    auto root = parent / "widget";
+    REQUIRE(std::filesystem::exists(root / "src" / "lib.cppm"));
+    REQUIRE_FALSE(std::filesystem::exists(root / "src" / "main.cpp"));
+
+    auto lib_src = read_file(root / "src" / "lib.cppm");
+    REQUIRE(lib_src.find("export module widget;") != std::string::npos);
+    REQUIRE(lib_src.find("export namespace widget") != std::string::npos);
+    REQUIRE(lib_src.find("Hello from widget!") != std::string::npos);
+}
+
+TEST_CASE("cmd_new replaces hyphens with underscores in module name",
+          "[cli][new]") {
+    auto parent = fresh_dir();
+    REQUIRE(cmd_new("my-project", true, parent).has_value());
+
+    auto m = manifest::parse(parent / "my-project" / "Cargoxx.toml");
+    REQUIRE(m->package.name == "my-project");
+
+    auto lib_src = read_file(parent / "my-project" / "src" / "lib.cppm");
+    REQUIRE(lib_src.find("export module my_project;") != std::string::npos);
+    REQUIRE(lib_src.find("Hello from my-project!") != std::string::npos);
+}
+
+TEST_CASE("cmd_new fails when target directory exists", "[cli][new]") {
+    auto parent = fresh_dir();
+    std::filesystem::create_directories(parent / "exists");
+    auto r = cmd_new("exists", false, parent);
+    REQUIRE_FALSE(r.has_value());
+    REQUIRE(r.error().code == ErrorCode::Internal);
+}
+
+TEST_CASE("cmd_new rejects an empty name", "[cli][new]") {
+    auto parent = fresh_dir();
+    auto r = cmd_new("", false, parent);
+    REQUIRE_FALSE(r.has_value());
+    REQUIRE(r.error().code == ErrorCode::LayoutInvalidName);
+}
+
+TEST_CASE("cmd_new rejects a name starting with a digit", "[cli][new]") {
+    auto parent = fresh_dir();
+    auto r = cmd_new("1bad", false, parent);
+    REQUIRE_FALSE(r.has_value());
+    REQUIRE(r.error().code == ErrorCode::LayoutInvalidName);
+}
+
+TEST_CASE("cmd_new rejects a name with a space", "[cli][new]") {
+    auto parent = fresh_dir();
+    auto r = cmd_new("foo bar", false, parent);
+    REQUIRE_FALSE(r.has_value());
+    REQUIRE(r.error().code == ErrorCode::LayoutInvalidName);
+}
+
+TEST_CASE("cmd_new writes a minimal .gitignore", "[cli][new]") {
+    auto parent = fresh_dir();
+    REQUIRE(cmd_new("foo", false, parent).has_value());
+    auto content = read_file(parent / "foo" / ".gitignore");
+    REQUIRE(content.find("/build/") != std::string::npos);
+}