main.c nicer interface

cmd/main.c

@@ -23,17 +23,47 @@ void step_through(struct l2_vm *vm) {
 	}
 }
 
-int main(int argc, char **argv) {
-	if (argc != 1 && argc != 2) {
-		fprintf(stderr, "Usage: %s [file]\n", argv[0]);
-		return 1;
-	}
+static void usage(const char *argv0) {
+	printf("Usage: %s [options] [input|-]\n", argv0);
+	printf("\n");
+	printf("Options:\n");
+	printf("  --help:      Print this help text\n");
+	printf("  --bytecode:  Print the generated bytecode, don't execute\n");
+	printf("  --step:      Step through the program\n");
+}
 
-	FILE *inf;
-	if (argc == 1 || (argc == 2 && strcmp(argv[1], "-") == 0)) {
-		inf = stdin;
-	} else {
-		inf = fopen(argv[1], "r");
+int main(int argc, char **argv) {
+	int do_print_bytecode = 0;
+	int do_step = 0;
+
+	int was_inf_set = 0;
+	FILE *inf = stdin;
+
+	int dashes = 0;
+	for (int i = 1; i < argc; ++i) {
+		if (!dashes && strcmp(argv[i], "--help") == 0) {
+			usage(argv[0]);
+			return 0;
+		} else if (!dashes && strcmp(argv[i], "--bytecode") == 0) {
+			do_print_bytecode = 1;
+		} else if (!dashes && strcmp(argv[i], "--step") == 0) {
+			do_step = 1;
+		} else if (strcmp(argv[i], "--") == 0) {
+			dashes = 1;
+		} else if (strcmp(argv[i], "-") == 0) {
+			inf = stdin;
+		} else if (!was_inf_set) {
+			inf = fopen(argv[i], "r");
+			was_inf_set = 1;
+			if (inf == NULL) {
+				perror(argv[i]);
+				return 1;
+			}
+		} else {
+			printf("Unexpected argument: %s\n", argv[i]);
+			usage(argv[0]);
+			return 1;
+		}
 	}
 
 	// Init lexer with its input reader
@@ -61,24 +91,21 @@ int main(int argc, char **argv) {
 	l2_gen_free(&gen);
 	fclose(inf);
 
-	printf("Generated bytecode:\n");
-	l2_vm_print_bytecode((l2_word *)w.mem, w.len / sizeof(l2_word));
-	printf("\n");
+	if (do_print_bytecode) {
+		l2_vm_print_bytecode((l2_word *)w.mem, w.len / sizeof(l2_word));
+		free(w.mem);
+		return 0;
+	}
 
 	struct l2_vm vm;
 	l2_vm_init(&vm, (void *)w.mem, w.len / sizeof(l2_word));
 
-	l2_vm_run(&vm);
-	free(w.mem);
-
-	printf("State before GC:\n");
-	l2_vm_print_state(&vm);
-	printf("\n");
-
-	while (l2_vm_gc(&vm));
-
-	printf("\nState after GC:\n");
-	l2_vm_print_state(&vm);
+	if (do_step) {
+		step_through(&vm);
+	} else {
+		l2_vm_run(&vm);
+	}
 
 	l2_vm_free(&vm);
+	free(w.mem);
 }