feat: system config DSL, services, CLI with rustc diagnostics

- System config parser (system/packages/services/boot/users blocks)
- Boot block: kernel, init, efi, swap, bootloader, root partition
- System-wide features, rollback config, swap partition
- Service block: per-init variants (runit, s6, etc.), system init selection via boot.init
- Feature-gated dependencies, config values accept numbers/bools/strings
- CLI: parse-package, parse-config, validate subcommands
- Rustc-style error diagnostics with source context, carets, help text
- Diagnostic module with ANSI color output

CMakeLists.txt

@@ -27,7 +27,9 @@ add_executable(kappa
   src/paths.cpp
   src/dsl/lexer.cpp
   src/dsl/parser.cpp
+  src/dsl/system.cpp
   src/eval/vars.cpp
+  src/cli/diagnostic.cpp
 )
 target_include_directories(kappa PRIVATE include)
 target_link_libraries(kappa PRIVATE tomlplusplus::tomlplusplus)

examples/config.kap

@@ -0,0 +1,87 @@
+/*
+ * Kappa system configuration.
+ * Lives at /kappa/system/config.kap
+ */
+system {
+    hostname = "kappa.local"
+    timezone = "America/New_York"
+
+    features {
+        ssl         = true
+        wayland     = false
+        pulseaudio  = false
+    }
+
+    env {
+        CFLAGS    = "-O2 -march=native"
+        LDFLAGS   = "-Wl,--as-needed"
+        MAKEFLAGS = "-j8"
+    }
+
+    config {
+        prefix  = "/usr"
+        log_dir = "/var/log"
+    }
+
+    rollback {
+        keep = 5
+    }
+}
+
+packages {
+    foo {
+        version = ">=1.2"
+        features {
+            gui = true
+        }
+        config {
+            port = "9090"
+            ssl  = true
+        }
+    }
+    bar {}
+    baz {
+        features {
+            ssl = false
+        }
+    }
+
+    /*
+    // Per-package overrides can also live in
+    // /kappa/system/builds/<name>.kap
+    */
+}
+
+services {
+    nginx {
+        enable = true
+        port   = 80
+        ssl    = true
+    }
+    sshd {
+        enable = true
+        port   = 22
+    }
+    cron {
+        enable = false
+    }
+}
+
+boot {
+    kernel     = "linux"
+    init       = "s6"
+    efi        = "/dev/sda2"
+    swap       = "/dev/sda3"
+    bootloader = "limine"
+    root       = "/dev/sda1"
+}
+
+users {
+    specter {
+        shell  = "/bin/zsh"
+        groups = ["wheel", "audio", "docker"]
+    }
+    root {
+        shell = "/bin/zsh"
+    }
+}

examples/foo.kap

@@ -59,6 +59,20 @@ package "foo" {
         CFLAGS  ?= "-g"
     }
 
+    service {
+        runit {
+            exec  = "/usr/bin/foo --daemon"
+            type  = "forking"
+            user  = "foo"
+        }
+        s6 {
+            exec  = "/usr/bin/foo"
+            type  = "longrun"
+            ports = [80, 443]
+            user  = "foo"
+        }
+    }
+
     prepare {
         patch "fix-build.patch"
     }

include/kappa/cli/diagnostic.hpp

@@ -0,0 +1,31 @@
+#pragma once
+
+#include <ostream>
+#include <string>
+#include <string_view>
+
+namespace kappa::cli {
+
+struct SourceLocation {
+    std::string_view file;
+    int line = 0;
+    int col  = 0;
+};
+
+void print_error(std::ostream& os,
+                 std::string_view source,
+                 SourceLocation loc,
+                 std::string_view message);
+
+void print_error(std::ostream& os,
+                 std::string_view source,
+                 SourceLocation loc,
+                 std::string_view message,
+                 std::string_view help);
+
+void print_note(std::ostream& os,
+                std::string_view source,
+                SourceLocation loc,
+                std::string_view message);
+
+} // namespace kappa::cli

include/kappa/dsl/ast.hpp

@@ -44,6 +44,14 @@ struct EnvEntry {
     bool soft = false;
 };
 
+struct ServiceInit {
+    std::string exec;
+    std::string type;
+    std::string user;
+    std::vector<int> ports;
+    std::unordered_map<std::string, std::string> env;
+};
+
 struct PackageDef {
     std::string name;
     std::string version;
@@ -56,6 +64,7 @@ struct PackageDef {
     std::vector<ConfigFile> config_files;
     std::vector<Patch> patches;
     std::vector<EnvEntry> env_entries;
+    std::unordered_map<std::string, ServiceInit> service;
     std::unordered_set<std::string> const_keys;
     Phase prepare;
     Phase build;

include/kappa/dsl/system.hpp

@@ -0,0 +1,64 @@
+#pragma once
+
+#include "kappa/dsl/ast.hpp"
+
+#include <string>
+#include <string_view>
+#include <unordered_map>
+#include <vector>
+
+namespace kappa::dsl {
+
+struct RollbackConfig {
+    int keep = 0;
+};
+
+struct SystemBlock {
+    std::string hostname;
+    std::string timezone;
+    std::vector<EnvEntry> env;
+    std::unordered_map<std::string, std::string> config;
+    std::unordered_map<std::string, FeatureDef> features;
+    RollbackConfig rollback;
+};
+
+struct PackageRef {
+    std::string name;
+    std::string version;
+    std::unordered_map<std::string, FeatureDef> features;
+    std::unordered_map<std::string, std::string> config;
+};
+
+struct BootBlock {
+    std::string kernel;
+    std::string init;
+    std::string efi;
+    std::string swap;
+    std::string bootloader;
+    std::unordered_map<std::string, std::string> params;
+};
+
+struct UserRef {
+    std::string name;
+    std::string shell;
+    std::vector<std::string> groups;
+    std::unordered_map<std::string, std::string> extra;
+};
+
+struct ServiceRef {
+    std::string name;
+    bool enable = false;
+    std::unordered_map<std::string, std::string> config;
+};
+
+struct SystemConfig {
+    SystemBlock system;
+    std::vector<PackageRef> packages;
+    std::vector<ServiceRef> services;
+    BootBlock boot;
+    std::vector<UserRef> users;
+};
+
+SystemConfig parse_system_config(std::string_view source);
+
+} // namespace kappa::dsl

include/kappa/dsl/token.hpp

@@ -34,6 +34,7 @@ enum class TokenType {
     KwLicense,
     KwPatches,
     KwEnv,
+    KwService,
     KwPrepare,
     KwBuild,
     KwCheck,

src/cli/diagnostic.cpp

@@ -0,0 +1,94 @@
+#include "kappa/cli/diagnostic.hpp"
+
+#include <algorithm>
+#include <format>
+#include <string_view>
+#include <vector>
+
+namespace kappa::cli {
+
+using namespace std::string_view_literals;
+
+static constexpr auto bold   = "\033[1m"sv;
+static constexpr auto red    = "\033[31m"sv;
+static constexpr auto cyan   = "\033[36m"sv;
+static constexpr auto yellow = "\033[33m"sv;
+static constexpr auto reset  = "\033[0m"sv;
+
+static std::string_view line_at(std::string_view source, int target_line) {
+    int current = 1;
+    std::size_t start = 0;
+    for (std::size_t i = 0; i < source.size(); ++i) {
+        if (current == target_line) { start = i; break; }
+        if (source[i] == '\n') { ++current; }
+    }
+    if (current != target_line) { return ""sv; }
+
+    auto end = source.find('\n', start);
+    if (end == std::string_view::npos) { end = source.size(); }
+    return source.substr(start, end - start);
+}
+
+static void print_header(std::ostream& os,
+                         std::string_view severity,
+                         std::string_view color,
+                         std::string_view file,
+                         int line, int col,
+                         std::string_view message) {
+    os << color << bold << severity << ": " << reset
+       << color << message << reset << '\n'
+       << "  " << cyan << "\u250C\u2500 " << file << ':' << line << ':' << col
+       << reset << '\n';
+}
+
+void print_error(std::ostream& os,
+                 std::string_view source,
+                 SourceLocation loc,
+                 std::string_view message) {
+    print_header(os, "error", red, loc.file, loc.line, loc.col, message);
+
+    auto line_src = line_at(source, loc.line);
+    if (!line_src.empty()) {
+        auto line_num = std::format("{}", loc.line);
+        os << "  " << cyan << "\u2502" << reset << '\n'
+           << ' ' << line_num << " " << cyan << "\u2502 " << reset
+           << line_src << '\n';
+
+        os << "  " << std::string(line_num.size(), ' ')
+           << ' ' << cyan << "\u2502 " << reset;
+        for (int i = 0; i < loc.col - 1; ++i) { os << ' '; }
+        os << red << bold << '^' << reset << '\n';
+    }
+
+    os << "  " << cyan << "\u2502" << reset << '\n';
+}
+
+void print_error(std::ostream& os,
+                 std::string_view source,
+                 SourceLocation loc,
+                 std::string_view message,
+                 std::string_view help) {
+    print_error(os, source, loc, message);
+    os << "  " << cyan << "\u2570\u2500\u2500 " << reset
+       << yellow << "help: " << reset << help << '\n';
+}
+
+void print_note(std::ostream& os,
+                std::string_view source,
+                SourceLocation loc,
+                std::string_view message) {
+    print_header(os, "note", cyan, loc.file, loc.line, loc.col, message);
+    auto line_src = line_at(source, loc.line);
+    if (!line_src.empty()) {
+        auto line_num = std::format("{}", loc.line);
+        os << "  " << cyan << "\u2502" << reset << '\n'
+           << ' ' << line_num << " " << cyan << "\u2502 " << reset
+           << line_src << '\n'
+           << "  " << std::string(line_num.size(), ' ')
+           << ' ' << cyan << "\u2502" << reset << '\n';
+    }
+    os << "  " << cyan << "\u2570\u2500\u2500 " << reset
+       << cyan << "note: " << reset << message << '\n';
+}
+
+} // namespace kappa::cli

src/dsl/lexer.cpp

@@ -19,6 +19,7 @@ static const std::unordered_map<std::string_view, TokenType> keywords = {
     {"license",  TokenType::KwLicense},
     {"patches",  TokenType::KwPatches},
     {"env",      TokenType::KwEnv},
+    {"service",  TokenType::KwService},
     {"prepare",  TokenType::KwPrepare},
     {"build",    TokenType::KwBuild},
     {"check",    TokenType::KwCheck},
@@ -51,6 +52,7 @@ std::string_view token_name(TokenType type) {
     case TokenType::KwLicense:  return "license";
     case TokenType::KwPatches:  return "patches";
     case TokenType::KwEnv:      return "env";
+    case TokenType::KwService:  return "service";
     case TokenType::KwPrepare:  return "prepare";
     case TokenType::KwBuild:    return "build";
     case TokenType::KwCheck:    return "check";

src/dsl/parser.cpp

@@ -209,6 +209,52 @@ void Parser::parse_body(PackageDef& pkg) {
             consume(TokenType::Rbrace);
             break;
 
+        case TokenType::KwService:
+            consume(TokenType::KwService);
+            consume(TokenType::Lbrace);
+            skip_newlines();
+            while (!at(TokenType::Rbrace) && !at(TokenType::Eof)) {
+                if (at(TokenType::Newline)) { advance(); continue; }
+                auto init_name = current_.lexeme;  // e.g. "runit", "s6"
+                advance();
+                consume(TokenType::Lbrace);
+                skip_newlines();
+                ServiceInit si;
+                while (!at(TokenType::Rbrace) && !at(TokenType::Eof)) {
+                    if (at(TokenType::Newline)) { advance(); continue; }
+                    auto key = current_.lexeme;
+                    advance();
+                    consume(TokenType::Equals);
+                    if (key == "exec") {
+                        si.exec = consume(TokenType::String).lexeme;
+                    } else if (key == "type") {
+                        si.type = consume(TokenType::String).lexeme;
+                    } else if (key == "user") {
+                        si.user = consume(TokenType::String).lexeme;
+                    } else if (key == "ports") {
+                        consume(TokenType::Lbracket);
+                        skip_newlines();
+                        while (!at(TokenType::Rbracket) && !at(TokenType::Eof)) {
+                            si.ports.push_back(
+                                std::stoi(std::string(current_.lexeme)));
+                            advance();
+                            skip_newlines();
+                            if (at(TokenType::Comma)) { consume(TokenType::Comma); }
+                            skip_newlines();
+                        }
+                        consume(TokenType::Rbracket);
+                    } else {
+                        si.env[key] = consume(TokenType::String).lexeme;
+                    }
+                    skip_newlines();
+                }
+                consume(TokenType::Rbrace);
+                pkg.service[std::string(init_name)] = std::move(si);
+                skip_newlines();
+            }
+            consume(TokenType::Rbrace);
+            break;
+
         case TokenType::KwPrepare:
             consume(TokenType::KwPrepare);
             pkg.prepare = parse_phase();

src/dsl/system.cpp

@@ -0,0 +1,358 @@
+#include "kappa/dsl/system.hpp"
+#include "kappa/dsl/lexer.hpp"
+
+#include <format>
+#include <stdexcept>
+
+namespace kappa::dsl {
+
+class ParseError : public std::runtime_error {
+public:
+    ParseError(int line, int col, const std::string& msg)
+        : std::runtime_error(std::format("{}:{}: {}", line, col, msg)) {}
+};
+
+class SysParser {
+public:
+    explicit SysParser(std::string_view source) : lexer_(source) { advance(); }
+
+    SystemConfig parse();
+
+private:
+    void  advance();
+    Token consume(TokenType type);
+    void  skip_newlines();
+    bool  at(TokenType type) const { return current_.type == type; }
+
+    bool parse_bool();
+    void parse_system_block(SystemConfig& cfg);
+    void parse_packages_block(SystemConfig& cfg);
+    void parse_services_block(SystemConfig& cfg);
+    void parse_boot_block(SystemConfig& cfg);
+    void parse_users_block(SystemConfig& cfg);
+
+    std::string consume_ident();
+    std::string consume_string();
+
+    Token current_;
+    Lexer lexer_;
+};
+
+void SysParser::advance() { current_ = lexer_.next(); }
+
+void SysParser::skip_newlines() {
+    while (at(TokenType::Newline)) { advance(); }
+}
+
+Token SysParser::consume(TokenType type) {
+    if (!at(type)) {
+        throw ParseError(current_.line, current_.col,
+                        std::format("expected '{}', got '{}'",
+                                    token_name(type), token_name(current_.type)));
+    }
+    Token t = std::move(current_);
+    advance();
+    return t;
+}
+
+std::string SysParser::consume_ident() {
+    if (at(TokenType::Ident) ||
+        at(TokenType::KwEnv) ||
+        at(TokenType::KwConfig) ||
+        at(TokenType::KwFeatures) ||
+        at(TokenType::KwVersion) ||
+        at(TokenType::KwSource) ||
+        at(TokenType::KwLicense) ||
+        at(TokenType::KwPatches) ||
+        at(TokenType::KwConst) ||
+        at(TokenType::KwPackage) ||
+        at(TokenType::KwDepends) ||
+        at(TokenType::KwProvides) ||
+        at(TokenType::KwOutputs) ||
+        at(TokenType::KwPrepare) ||
+        at(TokenType::KwBuild) ||
+        at(TokenType::KwCheck) ||
+        at(TokenType::KwInstall) ||
+        at(TokenType::KwTrue) ||
+        at(TokenType::KwFalse)) {
+        auto lexeme = current_.lexeme;
+        advance();
+        return lexeme;
+    }
+    throw ParseError(current_.line, current_.col,
+                    std::format("expected identifier, got '{}'",
+                                token_name(current_.type)));
+}
+
+std::string SysParser::consume_string() {
+    if (at(TokenType::KwTrue))  { advance(); return "true"; }
+    if (at(TokenType::KwFalse)) { advance(); return "false"; }
+    return consume(TokenType::String).lexeme;
+}
+
+bool SysParser::parse_bool() {
+    if (at(TokenType::KwTrue))  { advance(); return true; }
+    if (at(TokenType::KwFalse)) { advance(); return false; }
+    throw ParseError(current_.line, current_.col,
+                    std::format("expected 'true' or 'false', got '{}'",
+                                token_name(current_.type)));
+}
+
+SystemConfig SysParser::parse() {
+    skip_newlines();
+    SystemConfig cfg;
+
+    while (!at(TokenType::Eof)) {
+        skip_newlines();
+        if (at(TokenType::Eof)) { break; }
+
+        auto kw = consume_ident();
+
+        if (kw == "system")   { parse_system_block(cfg); }
+        else if (kw == "packages") { parse_packages_block(cfg); }
+        else if (kw == "services") { parse_services_block(cfg); }
+        else if (kw == "boot")     { parse_boot_block(cfg); }
+        else if (kw == "users")    { parse_users_block(cfg); }
+        else {
+            throw ParseError(current_.line, current_.col,
+                           std::format("unknown section '{}'", kw));
+        }
+    }
+
+    return cfg;
+}
+
+void SysParser::parse_system_block(SystemConfig& cfg) {
+    consume(TokenType::Lbrace);
+    skip_newlines();
+
+    while (!at(TokenType::Rbrace) && !at(TokenType::Eof)) {
+        skip_newlines();
+        if (at(TokenType::Rbrace)) { break; }
+
+        auto key = consume_ident();
+        if (key == "hostname") {
+            consume(TokenType::Equals);
+            cfg.system.hostname = consume_string();
+        } else if (key == "timezone") {
+            consume(TokenType::Equals);
+            cfg.system.timezone = consume_string();
+        } else if (key == "env") {
+            consume(TokenType::Lbrace);
+            skip_newlines();
+            while (!at(TokenType::Rbrace) && !at(TokenType::Eof)) {
+                if (at(TokenType::Newline)) { advance(); continue; }
+                auto k = consume_ident();
+                bool soft = false;
+                if (at(TokenType::Ident) && current_.lexeme == "?=") {
+                    soft = true;
+                    advance();
+                } else {
+                    consume(TokenType::Equals);
+                }
+                cfg.system.env.push_back({std::move(k), consume_string(), soft});
+                skip_newlines();
+            }
+            consume(TokenType::Rbrace);
+        } else if (key == "config") {
+            consume(TokenType::Lbrace);
+            skip_newlines();
+            while (!at(TokenType::Rbrace) && !at(TokenType::Eof)) {
+                if (at(TokenType::Newline)) { advance(); continue; }
+                auto k = consume_ident();
+                consume(TokenType::Equals);
+                cfg.system.config[k] = consume_string();
+                skip_newlines();
+            }
+            consume(TokenType::Rbrace);
+        } else if (key == "features") {
+            consume(TokenType::Lbrace);
+            skip_newlines();
+            while (!at(TokenType::Rbrace) && !at(TokenType::Eof)) {
+                if (at(TokenType::Newline)) { advance(); continue; }
+                auto k = consume_ident();
+                consume(TokenType::Equals);
+                cfg.system.features[k] = FeatureDef{parse_bool(), false, ""};
+                skip_newlines();
+            }
+            consume(TokenType::Rbrace);
+        } else if (key == "rollback") {
+            consume(TokenType::Lbrace);
+            skip_newlines();
+            while (!at(TokenType::Rbrace) && !at(TokenType::Eof)) {
+                if (at(TokenType::Newline)) { advance(); continue; }
+                auto k = consume_ident();
+                consume(TokenType::Equals);
+                if (k == "keep") {
+                    cfg.system.rollback.keep = std::stoi(std::string(current_.lexeme));
+                    advance();
+                }
+                skip_newlines();
+            }
+            consume(TokenType::Rbrace);
+        } else {
+            throw ParseError(current_.line, current_.col,
+                           std::format("unknown system key '{}'", key));
+        }
+    }
+    consume(TokenType::Rbrace);
+}
+
+void SysParser::parse_packages_block(SystemConfig& cfg) {
+    consume(TokenType::Lbrace);
+    skip_newlines();
+
+    while (!at(TokenType::Rbrace) && !at(TokenType::Eof)) {
+        skip_newlines();
+        if (at(TokenType::Rbrace)) { break; }
+
+        PackageRef pkg;
+        pkg.name = consume_ident();
+
+        if (at(TokenType::Lbrace)) {
+            consume(TokenType::Lbrace);
+            skip_newlines();
+            while (!at(TokenType::Rbrace) && !at(TokenType::Eof)) {
+                skip_newlines();
+                if (at(TokenType::Rbrace)) { break; }
+                auto key = consume_ident();
+                if (key == "version") {
+                    consume(TokenType::Equals);
+                    pkg.version = consume_string();
+                } else if (key == "features") {
+                    consume(TokenType::Lbrace);
+                    skip_newlines();
+                    while (!at(TokenType::Rbrace) && !at(TokenType::Eof)) {
+                        if (at(TokenType::Newline)) { advance(); continue; }
+                        auto k = consume_ident();
+                        consume(TokenType::Equals);
+                        pkg.features[k] = FeatureDef{parse_bool(), false, ""};
+                        skip_newlines();
+                    }
+                    consume(TokenType::Rbrace);
+                } else if (key == "config") {
+                    consume(TokenType::Lbrace);
+                    skip_newlines();
+                    while (!at(TokenType::Rbrace) && !at(TokenType::Eof)) {
+                        if (at(TokenType::Newline)) { advance(); continue; }
+                        auto k = consume_ident();
+                        consume(TokenType::Equals);
+                        pkg.config[k] = current_.lexeme;
+                        advance();
+                        skip_newlines();
+                    }
+                    consume(TokenType::Rbrace);
+                }
+            }
+            consume(TokenType::Rbrace);
+        }
+        cfg.packages.push_back(std::move(pkg));
+    }
+    consume(TokenType::Rbrace);
+}
+
+void SysParser::parse_services_block(SystemConfig& cfg) {
+    consume(TokenType::Lbrace);
+    skip_newlines();
+
+    while (!at(TokenType::Rbrace) && !at(TokenType::Eof)) {
+        skip_newlines();
+        if (at(TokenType::Rbrace)) { break; }
+
+        ServiceRef svc;
+        svc.name = consume_ident();
+
+        if (at(TokenType::Lbrace)) {
+            consume(TokenType::Lbrace);
+            skip_newlines();
+            while (!at(TokenType::Rbrace) && !at(TokenType::Eof)) {
+                if (at(TokenType::Newline)) { advance(); continue; }
+                auto key = consume_ident();
+                if (key == "enable") {
+                    consume(TokenType::Equals);
+                    svc.enable = parse_bool();
+                } else {
+                    consume(TokenType::Equals);
+                    svc.config[key] = current_.lexeme;
+                    advance();
+                }
+                skip_newlines();
+            }
+            consume(TokenType::Rbrace);
+        }
+        cfg.services.push_back(std::move(svc));
+    }
+    consume(TokenType::Rbrace);
+}
+
+void SysParser::parse_boot_block(SystemConfig& cfg) {
+    consume(TokenType::Lbrace);
+    skip_newlines();
+
+    while (!at(TokenType::Rbrace) && !at(TokenType::Eof)) {
+        skip_newlines();
+        if (at(TokenType::Rbrace)) { break; }
+        auto key = consume_ident();
+        consume(TokenType::Equals);
+        auto val = consume_string();
+        if (key == "kernel") { cfg.boot.kernel = std::move(val); }
+        else if (key == "init")      { cfg.boot.init = std::move(val); }
+        else if (key == "efi")       { cfg.boot.efi = std::move(val); }
+        else if (key == "swap")      { cfg.boot.swap = std::move(val); }
+        else if (key == "bootloader"){ cfg.boot.bootloader = std::move(val); }
+        else { cfg.boot.params[key] = std::move(val); }
+        skip_newlines();
+    }
+    consume(TokenType::Rbrace);
+}
+
+void SysParser::parse_users_block(SystemConfig& cfg) {
+    consume(TokenType::Lbrace);
+    skip_newlines();
+
+    while (!at(TokenType::Rbrace) && !at(TokenType::Eof)) {
+        skip_newlines();
+        if (at(TokenType::Rbrace)) { break; }
+
+        UserRef u;
+        u.name = consume_ident();
+
+        if (at(TokenType::Lbrace)) {
+            consume(TokenType::Lbrace);
+            skip_newlines();
+            while (!at(TokenType::Rbrace) && !at(TokenType::Eof)) {
+                if (at(TokenType::Newline)) { advance(); continue; }
+                auto key = consume_ident();
+                if (key == "shell") {
+                    consume(TokenType::Equals);
+                    u.shell = consume_string();
+                } else if (key == "groups") {
+                    consume(TokenType::Equals);
+                    consume(TokenType::Lbracket);
+                    skip_newlines();
+                    while (!at(TokenType::Rbracket) && !at(TokenType::Eof)) {
+                        u.groups.push_back(consume_string());
+                        skip_newlines();
+                        if (at(TokenType::Comma)) { consume(TokenType::Comma); }
+                        skip_newlines();
+                    }
+                    consume(TokenType::Rbracket);
+                } else {
+                    consume(TokenType::Equals);
+                    u.extra[key] = consume_string();
+                }
+                skip_newlines();
+            }
+            consume(TokenType::Rbrace);
+        }
+        cfg.users.push_back(std::move(u));
+    }
+    consume(TokenType::Rbrace);
+}
+
+SystemConfig parse_system_config(std::string_view source) {
+    SysParser p(source);
+    return p.parse();
+}
+
+} // namespace kappa::dsl

src/main.cpp

@@ -1,28 +1,151 @@
-#include "kappa/package.hpp"
+#include "kappa/cli/diagnostic.hpp"
+#include "kappa/dsl/parser.hpp"
+#include "kappa/dsl/system.hpp"
 
-#include <toml++/toml.hpp>
 #include <cstdlib>
-#include <exception>
-#include <filesystem>
+#include <fstream>
 #include <iostream>
+#include <sstream>
+#include <string_view>
+
+using namespace std::string_view_literals;
+using namespace kappa;
+
+static constexpr auto version = "kappa 0.1.0"sv;
+
+static void print_usage() {
+    std::cout << R"(kappa — a declarative source-based package manager
+
+Usage:
+  kappa <subcommand> [options] <file>
+
+Subcommands:
+  parse-package <file>    Parse and validate a package definition (.kap)
+  parse-config  <file>    Parse and validate a system configuration
+  validate      <file>    Validate any kappa file (package or config)
+
+Options:
+  -h, --help              Show this help message
+  -V, --version           Show version information
+)";
+}
+
+static bool is_flag(std::string_view arg) {
+    return arg == "-h" || arg == "--help" || arg == "-V" || arg == "--version";
+}
+
+static std::string read_file(const char* path) {
+    std::ifstream in(path);
+    if (!in) {
+        std::cerr << "error: cannot open '" << path << "'\n";
+        std::exit(1);
+    }
+    std::ostringstream buf;
+    buf << in.rdbuf();
+    return buf.str();
+}
+
+static void handle_parse_error(const char* path,
+                               std::string_view source,
+                               const std::runtime_error& e) {
+    // ParseError format: "line:col: message"
+    auto msg = std::string_view(e.what());
+    auto first_colon = msg.find(':');
+    auto second_colon = msg.find(':', first_colon + 1);
+
+    if (first_colon != std::string_view::npos &&
+        second_colon != std::string_view::npos) {
+        int line = std::stoi(std::string(msg.substr(0, first_colon)));
+        int col  = std::stoi(std::string(
+            msg.substr(first_colon + 1, second_colon - first_colon - 1)));
+        auto message = msg.substr(second_colon + 2); // skip ": "
+
+        cli::print_error(std::cerr, source,
+                         {path, line, col}, message,
+                         "check the syntax at this location");
+    } else {
+        std::cerr << "error: " << e.what() << '\n';
+    }
+}
 
 int main(int argc, char* argv[]) {
-    std::filesystem::path toml_path = (argc > 1) ? argv[1] : "package.toml";
-
-    if (!std::filesystem::exists(toml_path)) {
-        std::cerr << "Error: '" << toml_path << "' not found\n";
+    if (argc < 2) {
+        std::cerr << "kappa: missing subcommand\n\n";
+        print_usage();
         return 1;
     }
 
-    try {
-        auto pkg = kappa::parse_package(toml_path.native());
-        kappa::print_package(std::cout, pkg);
+    auto subcommand = std::string_view(argv[1]);
+
+    if (subcommand == "-h" || subcommand == "--help") {
+        print_usage();
         return 0;
-    } catch (const toml::parse_error& e) {
-        std::cerr << "Parse error:\n" << e << '\n';
+    }
+    if (subcommand == "-V" || subcommand == "--version") {
+        std::cout << version << '\n';
+        return 0;
+    }
+
+    // Find the file argument (skip flags)
+    const char* file_arg = nullptr;
+    for (int i = 2; i < argc; ++i) {
+        if (!is_flag(argv[i])) {
+            file_arg = argv[i];
+            break;
+        }
+    }
+
+    if (file_arg == nullptr) {
+        std::cerr << "error: no input file specified\n";
         return 1;
-    } catch (const std::exception& e) {
-        std::cerr << "Error: " << e.what() << '\n';
+    }
+
+    auto source = read_file(file_arg);
+
+    if (subcommand == "parse-package") {
+        try {
+            auto pkg = dsl::parse(source);
+            std::cout << "package \"" << pkg.name << "\" " << pkg.version
+                      << " — valid\n";
+            return 0;
+        } catch (const std::runtime_error& e) {
+            handle_parse_error(file_arg, source, e);
             return 1;
         }
     }
+
+    if (subcommand == "parse-config") {
+        try {
+            auto cfg = dsl::parse_system_config(source);
+            std::cout << "system config — valid ("
+                      << cfg.packages.size() << " packages, "
+                      << cfg.services.size() << " services, "
+                      << cfg.users.size() << " users)\n";
+            return 0;
+        } catch (const std::runtime_error& e) {
+            handle_parse_error(file_arg, source, e);
+            return 1;
+        }
+    }
+
+    if (subcommand == "validate") {
+        try {
+            dsl::parse(source);
+            std::cout << file_arg << ": valid package definition\n";
+            return 0;
+        } catch (const std::runtime_error&) {
+            try {
+                dsl::parse_system_config(source);
+                std::cout << file_arg << ": valid system configuration\n";
+                return 0;
+            } catch (const std::runtime_error& e) {
+                handle_parse_error(file_arg, source, e);
+                return 1;
+            }
+        }
+    }
+
+    std::cerr << "error: unknown subcommand '" << subcommand << "'\n\n";
+    print_usage();
+    return 1;
+}