diff --git a/CMakeLists.txt b/CMakeLists.txt
index ca09790..d3763ea 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -27,6 +27,8 @@ set(CMAKE_C_STANDARD_REQUIRED TRUE)
 set(GEMSTONE_TEST_DIR ${PROJECT_SOURCE_DIR}/tests)
 set(GEMSTONE_BINARY_DIR ${PROJECT_SOURCE_DIR}/bin)
 
+add_compile_definitions(GSC_VERSION="${PROJECT_VERSION}")
+
 include(CTest)
 
 if(BUILD_TESTING)
@@ -144,6 +146,9 @@ target_compile_options(release PUBLIC ${FLAGS} ${RELEASE_FLAGS})
 # add src directory as include path
 target_include_directories(release PUBLIC src)
 
+# disable assertions
+target_compile_definitions(release PUBLIC NDEBUG="1")
+
 # ------------------------------------------------ #
 #  Target DEBUG                                    #
 # ------------------------------------------------ #
diff --git a/src/cfg/opt.c b/src/cfg/opt.c
index feeafcb..ca22b6a 100644
--- a/src/cfg/opt.c
+++ b/src/cfg/opt.c
@@ -4,41 +4,47 @@
 
 #include <cfg/opt.h>
 #include <string.h>
+#include <sys/log.h>
 
-#define MAX_TARGETS_PER_PROJECT 100
+TargetConfig* default_target_config() {
+    DEBUG("generating default target config...");
 
-TargetConfig default_target_config() {
-    TargetConfig config;
+    TargetConfig* config = malloc(sizeof(TargetConfig));
 
-    config.name = "debug";
-    config.print_ast = false;
-    config.print_asm = false;
-    config.print_ir = false;
-    config.mode = Application;
-    config.archive_directory = "archive";
-    config.archive_directory = "bin";
-    config.optimization_level = 1;
-    config.root_module = NULL;
+    config->name = NULL;
+    config->print_ast = false;
+    config->print_asm = false;
+    config->print_ir = false;
+    config->mode = Application;
+    config->archive_directory = NULL;
+    config->archive_directory = NULL;
+    config->optimization_level = 1;
+    config->root_module = NULL;
 
     return config;
 }
 
-TargetConfig default_target_config_from_args(int argc, char *argv[]) {
-    TargetConfig config = default_target_config();
+TargetConfig* default_target_config_from_args(int argc, char *argv[]) {
+    DEBUG("generating default target from command line...");
+
+    TargetConfig* config = default_target_config();
 
     for (int i = 0; i < argc; i++) {
+        DEBUG("processing argument: %ld %s", i, argv[i]);
         char *option = argv[i];
 
         if (strcmp(option, "--print-ast") == 0) {
-            config.print_ast = true;
+            config->print_ast = true;
         } else if (strcmp(option, "--print-asm") == 0) {
-            config.print_asm = true;
+            config->print_asm = true;
         } else if (strcmp(option, "--print-ir") == 0) {
-            config.print_ir = true;
+            config->print_ir = true;
         } else if (strcmp(option, "--mode=app") == 0) {
-            config.mode = Application;
+            config->mode = Application;
         } else if (strcmp(option, "--mode=lib") == 0) {
-            config.mode = Library;
+            config->mode = Library;
+        } else {
+            config->root_module = option;
         }
     }
 
@@ -46,11 +52,14 @@ TargetConfig default_target_config_from_args(int argc, char *argv[]) {
 }
 
 void print_help(void) {
+    DEBUG("printing help dialog...");
+
     const char *lines[] = {
-            "Gemstone Compiler (C) GPL-2.0\n",
-            "Compile file(s): gsc <options> [files]",
-            "Build project (build.toml): gsc [directory] [target]|all",
+            "Gemstone Compiler (C) GPL-2.0",
+            "Build a project target: gsc build [target]|all",
+            "Compile non-project file: gsc compile <options> [file]",
             "Options:",
+            "    --version        print the version",
             "    --print-ast      print resulting abstract syntax tree to a file",
             "    --print-asm      print resulting assembly language to a file",
             "    --print-ir       print resulting LLVM-IR to a file",
@@ -62,35 +71,42 @@ void print_help(void) {
     }
 }
 
-#define PROJECT_OK 0
-#define PROJECT_TOML_ERR 1
-#define PROJECT_SEMANTIC_ERR 2
-
 static void get_bool(bool* boolean, toml_table_t *table, const char* name) {
+    DEBUG("retrieving boolean %s", name);
+
     toml_datum_t datum = toml_bool_in(table, name);
 
     if (datum.ok) {
         *boolean = datum.u.b;
+        DEBUG("boolean has value: %d", datum.u.b);
     }
 }
 
 static void get_str(char** string, toml_table_t *table, const char* name) {
+    DEBUG("retrieving string %s", name);
+
     toml_datum_t datum = toml_string_in(table, name);
 
     if (datum.ok) {
         *string = datum.u.s;
+        DEBUG("string has value: %s", datum.u.s);
     }
 }
 
 static void get_int(int* integer, toml_table_t *table, const char* name) {
+    DEBUG("retrieving integer %s", name);
+
     toml_datum_t datum = toml_int_in(table, name);
 
     if (datum.ok) {
         *integer = (int) datum.u.i;
+        DEBUG("integer has value: %ld", datum.u.i);
     }
 }
 
 static int parse_project_table(ProjectConfig *config, toml_table_t *project_table) {
+    DEBUG("parsing project table...");
+
     // project name
     get_str(&config->name, project_table, "version");
     if (config->name == NULL) {
@@ -99,7 +115,7 @@ static int parse_project_table(ProjectConfig *config, toml_table_t *project_tabl
     }
 
     // project version
-    get_str(&config->name, project_table, "version");
+    get_str(&config->name, project_table, "name");
 
     // author names
     toml_array_t *authors = toml_array_in(project_table, "authors");
@@ -136,34 +152,44 @@ static int get_mode_from_str(TargetCompilationMode* mode, const char* name) {
 }
 
 static int parse_target(ProjectConfig *config, toml_table_t *target_table, const char* name) {
-    TargetConfig target_config = default_target_config();
+    DEBUG("parsing target table...");
 
-    target_config.name = (char*) name;
+    TargetConfig* target_config = default_target_config();
 
-    get_bool(&target_config.print_ast, target_table, "print_ast");
-    get_bool(&target_config.print_asm, target_table, "print_asm");
-    get_bool(&target_config.print_ir, target_table, "print_ir");
+    target_config->name = (char*) name;
 
-    get_str(&target_config.root_module, target_table, "root");
-    get_str(&target_config.output_directory, target_table, "output");
-    get_str(&target_config.archive_directory, target_table, "archive");
+    get_bool(&target_config->print_ast, target_table, "print_ast");
+    get_bool(&target_config->print_asm, target_table, "print_asm");
+    get_bool(&target_config->print_ir, target_table, "print_ir");
 
-    get_int(&target_config.optimization_level, target_table, "opt");
+    get_str(&target_config->root_module, target_table, "root");
+    get_str(&target_config->output_directory, target_table, "output");
+    get_str(&target_config->archive_directory, target_table, "archive");
+
+    get_int(&target_config->optimization_level, target_table, "opt");
 
     char* mode = NULL;
     get_str(&mode, target_table, "mode");
-    int err = get_mode_from_str(&target_config.mode, mode);
+    int err = get_mode_from_str(&target_config->mode, mode);
     if (err != PROJECT_OK) {
         return err;
     }
 
-    g_array_append_val(config->targets, target_config);
+    g_hash_table_insert(config->targets, target_config->name, target_config);
 
     return PROJECT_OK;
 }
 
 static int parse_targets(ProjectConfig *config, toml_table_t *root) {
+    DEBUG("parsing targets of project \"%s\"", config->name);
+
     toml_table_t *targets = toml_table_in(root, "target");
+    if (targets == NULL) {
+        printf("Project has no targets\n");
+        return PROJECT_SEMANTIC_ERR;
+    }
+
+    config->targets = g_hash_table_new(g_str_hash, g_str_equal);
 
     for (int i = 0; i < MAX_TARGETS_PER_PROJECT; i++) {
         const char *key = toml_key_in(targets, i);
@@ -179,8 +205,12 @@ static int parse_targets(ProjectConfig *config, toml_table_t *root) {
 }
 
 int load_project_config(ProjectConfig *config) {
-    FILE *config_file = fopen("build.toml", "r");
+    DEBUG("loading project config...");
+
+    FILE *config_file = fopen(PROJECT_CONFIG_FILE, "r");
     if (config_file == NULL) {
+        printf("Cannot open file %s: %s\n", PROJECT_CONFIG_FILE, strerror(errno));
+        ERROR("project file not found");
         return PROJECT_TOML_ERR;
     }
 
@@ -197,7 +227,7 @@ int load_project_config(ProjectConfig *config) {
     toml_table_t *project = toml_table_in(conf, "project");
     if (project) {
         if (parse_project_table(config, project) == PROJECT_OK) {
-            return parse_targets(config, project);
+            return parse_targets(config, conf);
         }
     } else {
         printf("Invalid project configuration: missing project table\n\n");
@@ -206,3 +236,62 @@ int load_project_config(ProjectConfig *config) {
     toml_free(conf);
     return PROJECT_SEMANTIC_ERR;
 }
+
+void delete_target_config(TargetConfig* config) {
+    if (config->root_module != NULL) {
+        free(config->root_module);
+    }
+    if (config->archive_directory != NULL) {
+        free(config->archive_directory);
+    }
+    if (config->name != NULL) {
+        free(config->name);
+    }
+    if (config->output_directory != NULL) {
+        free(config->output_directory);
+    }
+    free(config);
+}
+
+void delete_project_config(ProjectConfig* config) {
+    if (config->name != NULL) {
+        free(config->name);
+    }
+    if (config->authors != NULL) {
+        g_array_free(config->authors, TRUE);
+    }
+    if (config->desc != NULL) {
+        free(config->desc);
+    }
+    if (config->license != NULL) {
+        free(config->license);
+    }
+    if (config->targets != NULL) {
+        GHashTableIter iter;
+
+        g_hash_table_iter_init(&iter, config->targets);
+
+        char* key;
+        TargetConfig* val;
+        while (g_hash_table_iter_next(&iter, (gpointer) &key, (gpointer) &val)) {
+            delete_target_config(val);
+        }
+
+        g_hash_table_destroy(config->targets);
+    }
+
+    free(config);
+}
+
+ProjectConfig* default_project_config() {
+    ProjectConfig* config = malloc(sizeof(ProjectConfig));
+
+    config->authors = NULL;
+    config->name = NULL;
+    config->targets = NULL;
+    config->license = NULL;
+    config->version = NULL;
+    config->desc = NULL;
+
+    return config;
+}
diff --git a/src/cfg/opt.h b/src/cfg/opt.h
index ec259e9..c54bfb2 100644
--- a/src/cfg/opt.h
+++ b/src/cfg/opt.h
@@ -8,6 +8,13 @@
 #include <toml.h>
 #include <glib.h>
 
+#define MAX_TARGETS_PER_PROJECT 100
+#define PROJECT_CONFIG_FILE "build.toml"
+
+#define PROJECT_OK 0
+#define PROJECT_TOML_ERR 1
+#define PROJECT_SEMANTIC_ERR 2
+
 typedef enum TargetCompilationMode_t {
     Application,
     Library
@@ -42,13 +49,21 @@ typedef struct ProjectConfig_t {
     char* license;
     // list of authors
     GArray* authors;
-    GArray* targets;
+    GHashTable* targets;
 } ProjectConfig;
 
-TargetConfig default_target_config();
+TargetConfig* default_target_config();
 
-TargetConfig default_target_config_from_args(int argc, char* argv[]);
+ProjectConfig* default_project_config();
+
+TargetConfig* default_target_config_from_args(int argc, char* argv[]);
+
+int load_project_config(ProjectConfig *config);
 
 void print_help(void);
 
+void delete_project_config(ProjectConfig* config);
+
+void delete_target_config(TargetConfig*);
+
 #endif //GEMSTONE_OPT_H
diff --git a/src/main.c b/src/main.c
index 4888ee5..c0be30b 100644
--- a/src/main.c
+++ b/src/main.c
@@ -6,6 +6,7 @@
 #include <lex/util.h>
 #include <io/files.h>
 #include <assert.h>
+#include <cfg/opt.h>
 
 extern void yyrestart(FILE *);
 
@@ -22,6 +23,7 @@ ModuleFile *current_file;
  */
 [[nodiscard("AST may be in invalid state")]]
 [[gnu::nonnull(1), gnu::nonnull(1)]]
+
 static size_t compile_file_to_ast(AST_NODE_PTR ast, ModuleFile *file) {
     assert(file->path != NULL);
     assert(ast != NULL);
@@ -30,6 +32,7 @@ static size_t compile_file_to_ast(AST_NODE_PTR ast, ModuleFile *file) {
 
     if (file->handle == NULL) {
         INFO("unable to open file: %s", file->path);
+        printf("Cannot open file %s: %s\n", file->path, strerror(errno));
         return 1;
     }
 
@@ -92,43 +95,117 @@ void setup(void) {
     DEBUG("finished starting up gemstone...");
 }
 
+void build_target(ModuleFileStack *unit, TargetConfig *target) {
+    printf("Compiling file: %s\n\n", target->root_module);
+
+    TokenLocation location = {
+            .line_start = 0,
+            .line_end = 0,
+            .col_start = 0,
+            .col_end = 0
+    };
+    AST_NODE_PTR ast = AST_new_node(location, AST_Module, NULL);
+    ModuleFile *file = push_file(unit, target->root_module);
+
+    if (compile_file_to_ast(ast, file) == EXIT_SUCCESS) {
+        // TODO: parse AST to semantic values
+        // TODO: backend codegen
+    }
+
+    AST_delete_node(ast);
+
+    print_file_statistics(file);
+}
+
+void compile_file(ModuleFileStack *unit, int argc, char *argv[]) {
+    INFO("compiling basic files...");
+
+    TargetConfig *target = default_target_config_from_args(argc, argv);
+
+    if (target->root_module == NULL) {
+        printf("No input file specified\n");
+        delete_target_config(target);
+        return;
+    }
+
+    build_target(unit, target);
+
+    delete_target_config(target);
+}
+
+void build_project_targets(ModuleFileStack *unit, ProjectConfig *config, const char *filter) {
+    if (strcmp(filter, "all") == 0) {
+        GHashTableIter iter;
+
+        g_hash_table_iter_init(&iter, config->targets);
+
+        char* key;
+        TargetConfig* val;
+        while (g_hash_table_iter_next(&iter, (gpointer) &key, (gpointer) &val)) {
+            build_target(unit, val);
+        }
+    } else if (g_hash_table_contains(config->targets, filter)) {
+        build_target(unit, g_hash_table_lookup(config->targets, filter));
+    }
+}
+
+void build_project(ModuleFileStack *unit, int argc, char *argv[]) {
+    if (argc >= 1) {
+        ProjectConfig* config = default_project_config();
+        int err = load_project_config(config);
+
+        if (err == PROJECT_OK) {
+            if (argc == 1) {
+                build_project_targets(unit, config, "all");
+            } else {
+                build_project_targets(unit, config, argv[0]);
+            }
+        }
+
+        delete_project_config(config);
+
+    } else {
+        printf("Expected 1 target to run\n");
+    }
+}
+
+void configure_run_mode(int argc, char *argv[]) {
+    if (argc > 1) {
+
+        ModuleFileStack files;
+        files.files = NULL;
+
+        if (strcmp(argv[1], "build") == 0) {
+            build_project(&files, argc - 2, &argv[2]);
+        } else if (strcmp(argv[1], "compile") == 0) {
+            compile_file(&files, argc - 2, &argv[2]);
+        } else {
+            printf("invalid mode of operation\n");
+        }
+
+        if (files.files == NULL) {
+            printf("No input files, nothing to do.\n\n");
+            exit(1);
+        }
+
+        print_unit_statistics(&files);
+        delete_files(&files);
+
+        return;
+    }
+    INFO("no arguments provided");
+
+    print_help();
+}
+
 int main(int argc, char *argv[]) {
 
     setup();
     atexit(close_file);
 
-    ModuleFileStack files;
-    files.files = NULL;
+    printf("running GSC version %s\n", GSC_VERSION);
 
-    for (int i = 1; i < argc; i++) {
-        printf("Compiling file: %s\n\n", argv[i]);
+    configure_run_mode(argc, argv);
 
-        TokenLocation location = {
-                .line_start = 0,
-                .line_end = 0,
-                .col_start = 0,
-                .col_end = 0
-        };
-        AST_NODE_PTR ast = AST_new_node(location, AST_Module, NULL);
-        ModuleFile *file = push_file(&files, argv[i]);
-
-        if (compile_file_to_ast(ast, file) == EXIT_SUCCESS) {
-            // TODO: parse AST to semantic values
-            // TODO: backend codegen
-        }
-
-        AST_delete_node(ast);
-
-        print_file_statistics(file);
-    }
-
-    if (files.files == NULL) {
-        printf("No input files, nothing to do.\n\n");
-        exit(1);
-    }
-
-    print_unit_statistics(&files);
-
-    delete_files(&files);
     return 0;
 }