+implemented tail recursion optimization in sub routine; +added array length gain in len function; *fixed a crash bug when returning nothing in a sub routine; *polished document.

HISTORY

@@ -1,3 +1,9 @@
+Sep. 21 2015
+Implemented tail recursion optimization in sub routine
+Added array length gain in LEN function
+Fixed a crash bug when returning nothing in a sub routine
+Polished document
+
 Sep. 20 2015
 Added array manipulation ability to script, it's able to assign an array to a variable or use it as a scripting interface argument
 Added recursive sub routine support
@@ -10,7 +16,7 @@ Added directly expression evaluation shell command
 Sep. 17 2015
 Allowed string in a boolean expression
 Added support for sub routine in PRINT
-Fixed a repeated disposing bug when suing sub routine
+Fixed a repeated disposing bug when using sub routine
 
 Sep. 16 2015
 Added Nil type handling, including assignment, boolean operation, serialization, etc.

core/my_basic.c

@@ -79,8 +79,12 @@ extern "C" {
 /** Macros */
 #define _VER_MAJOR 1
 #define _VER_MINOR 1
-#define _VER_REVISION 72
+#define _VER_REVISION 73
+#define _VER_SUFFIX
 #define _MB_VERSION ((_VER_MAJOR * 0x01000000) + (_VER_MINOR * 0x00010000) + (_VER_REVISION))
+#define _STRINGIZE(A) _MAKE_STRINGIZE(A)
+#define _MAKE_STRINGIZE(A) #A
+#define _MB_VERSION_STRING _STRINGIZE(_VER_MAJOR._VER_MINOR._VER_REVISION _VER_SUFFIX)
 
 /* Uncomment the line below to treat warning as error */
 /*#define _WARING_AS_ERROR*/
@@ -407,6 +411,7 @@ typedef struct mb_interpreter_t {
 	_parsing_context_t* parsing_context;
 	_running_context_t* running_context;
 	unsigned char jump_set;
+	_routine_t* last_routine;
 	_ls_node_t* sub_stack;
 	_ls_node_t* temp_values;
 	_ls_node_t* suspent_point;
@@ -985,11 +990,11 @@ static int _std_log(mb_interpreter_t* s, void** l);
 static int _std_asc(mb_interpreter_t* s, void** l);
 static int _std_chr(mb_interpreter_t* s, void** l);
 static int _std_left(mb_interpreter_t* s, void** l);
-static int _std_len(mb_interpreter_t* s, void** l);
 static int _std_mid(mb_interpreter_t* s, void** l);
 static int _std_right(mb_interpreter_t* s, void** l);
 static int _std_str(mb_interpreter_t* s, void** l);
 static int _std_val(mb_interpreter_t* s, void** l);
+static int _std_len(mb_interpreter_t* s, void** l);
 static int _std_print(mb_interpreter_t* s, void** l);
 static int _std_input(mb_interpreter_t* s, void** l);
 
@@ -1075,12 +1080,13 @@ static const _func_t _std_libs[] = {
 	{ "ASC", _std_asc },
 	{ "CHR", _std_chr },
 	{ "LEFT", _std_left },
-	{ "LEN", _std_len },
 	{ "MID", _std_mid },
 	{ "RIGHT", _std_right },
 	{ "STR", _std_str },
 	{ "VAL", _std_val },
 
+	{ "LEN", _std_len },
+
 	{ "PRINT", _std_print },
 	{ "INPUT", _std_input }
 };
@@ -1839,6 +1845,8 @@ int _calc_expression(mb_interpreter_t* s, _ls_node_t** l, _object_t** val) {
 					memset(c, 0, sizeof(_object_t));
 					_ls_pushback(garbage, c);
 					result = _public_value_to_internal_object(&running->intermediate_value, c);
+					if(c->type == _DT_STRING)
+						c->ref = true;
 					if(result != MB_FUNC_OK)
 						goto _exit;
 					if(f) {
@@ -2018,9 +2026,27 @@ int _eval_routine(mb_interpreter_t* s, _ls_node_t** l, _routine_t* r) {
 	_var_t* var = 0;
 	_ls_node_t* rnode = 0;
 	_running_context_t* running = 0;
+	_routine_t* lastr = 0;
 
 	mb_assert(s && l && r);
 
+	if(s->last_routine && (s->last_routine->name == r->name || !strcmp(s->last_routine->name, r->name))) {
+		ast = (_ls_node_t*)(*l);
+		_skip_to(s, &ast, 0, _DT_EOS);
+		if(ast && ((_object_t*)(ast->data))->type == _DT_EOS)
+			ast = ast->next;
+		if(_IS_FUNC((_object_t*)(ast->data), _core_enddef)) { /* Tail recursion optimization */
+			*l = r->entry;
+			if(*l)
+				*l = (*l)->next;
+
+			goto _tail;
+		}
+	}
+
+	lastr = s->last_routine;
+	s->last_routine = r;
+
 	running = s->running_context;
 
 	mb_check(mb_attempt_open_bracket(s, (void**)l));
@@ -2094,6 +2120,9 @@ int _eval_routine(mb_interpreter_t* s, _ls_node_t** l, _routine_t* r) {
 	s->running_context->intermediate_value = running->intermediate_value;
 
 _exit:
+	s->last_routine = lastr;
+
+_tail:
 	return result;
 }
 
@@ -3846,6 +3875,8 @@ int _execute_statement(mb_interpreter_t* s, _ls_node_t** l) {
 			ast = (_ls_node_t*)_ls_popback(sub_stack);
 		} else if(obj && obj->type == _DT_FUNC && (_is_operator(obj->data.func->pointer) || _is_flow(obj->data.func->pointer))) {
 			ast = ast->next;
+		} else if(obj && obj->type == _DT_FUNC) {
+			/* Do nothing */
 		} else if(obj && obj->type != _DT_FUNC) {
 			ast = ast->next;
 		} else {
@@ -4162,11 +4193,7 @@ unsigned int mb_ver(void) {
 
 const char* mb_ver_string(void) {
 	/* Get the version text of this MY-BASIC system */
-	static char buf[32] = { '\0' };
+	return _MB_VERSION_STRING;
-	if(!buf[0])
-		sprintf(buf, "%d.%d.%04d", _VER_MAJOR, _VER_MINOR, _VER_REVISION);
-
-	return buf;
 }
 
 int mb_init(void) {
@@ -4353,6 +4380,7 @@ int mb_reset(struct mb_interpreter_t** s, bool_t clrf/* = false*/) {
 	mb_assert(s);
 
 	(*s)->jump_set = _JMP_NIL;
+	(*s)->last_routine = 0;
 	(*s)->no_eat_comma_mark = 0;
 	(*s)->last_error = SE_NO_ERR;
 	(*s)->last_error_func = 0;
@@ -6344,6 +6372,7 @@ int _core_return(mb_interpreter_t* s, void** l) {
 	if(running->prev) {
 		ast = (_ls_node_t*)(*l);
 		ast = ast->next;
+		if(mb_has_arg(s, (void**)(&ast))) {
 			mb_check(mb_pop_value(s, (void**)(&ast), &arg));
 			mb_check(mb_push_value(s, (void**)(&ast), arg));
 
@@ -6352,6 +6381,7 @@ int _core_return(mb_interpreter_t* s, void** l) {
 				_ls_clear(s->temp_values);
 			}
 		}
+	}
 	ast = (_ls_node_t*)_ls_popback(sub_stack);
 	if(!ast) {
 		_handle_error_on_obj(s, SE_RN_NO_RETURN_POINT, 0, DON(ast), MB_FUNC_ERR, _exit, result);
@@ -7027,43 +7057,6 @@ _exit:
 	return result;
 }
 
-int _std_len(mb_interpreter_t* s, void** l) {
-	/* Get the length of a string */
-	int result = MB_FUNC_OK;
-	_ls_node_t* ast = 0;
-	mb_value_t arg;
-	_array_t* arr = 0;
-
-	mb_assert(s && l);
-
-	ast = (_ls_node_t*)(*l);
-
-	mb_check(mb_attempt_open_bracket(s, l));
-
-	mb_check(mb_pop_value(s, l, &arg));
-
-	mb_check(mb_attempt_close_bracket(s, l));
-
-	switch(arg.type) {
-	case MB_DT_STRING:
-		mb_check(mb_push_int(s, l, (int_t)strlen(arg.value.string)));
-
-		break;
-	case MB_DT_ARRAY:
-		arr = (_array_t*)arg.value.array;
-		mb_check(mb_push_int(s, l, (int_t)arr->count));
-
-		break;
-	default:
-		_handle_error_on_obj(s, SE_RN_NOT_SUPPORTED, 0, DON(ast), MB_FUNC_ERR, _exit, result);
-
-		break;
-	}
-
-_exit:
-	return result;
-}
-
 int _std_mid(mb_interpreter_t* s, void** l) {
 	/* Get a number of characters from a given position of a string */
 	int result = MB_FUNC_OK;
@@ -7194,6 +7187,43 @@ _exit:
 	return result;
 }
 
+int _std_len(mb_interpreter_t* s, void** l) {
+	/* Get the length of a string or an array */
+	int result = MB_FUNC_OK;
+	_ls_node_t* ast = 0;
+	mb_value_t arg;
+	_array_t* arr = 0;
+
+	mb_assert(s && l);
+
+	ast = (_ls_node_t*)(*l);
+
+	mb_check(mb_attempt_open_bracket(s, l));
+
+	mb_check(mb_pop_value(s, l, &arg));
+
+	mb_check(mb_attempt_close_bracket(s, l));
+
+	switch(arg.type) {
+	case MB_DT_STRING:
+		mb_check(mb_push_int(s, l, (int_t)strlen(arg.value.string)));
+
+		break;
+	case MB_DT_ARRAY:
+		arr = (_array_t*)arg.value.array;
+		mb_check(mb_push_int(s, l, (int_t)arr->count));
+
+		break;
+	default:
+		_handle_error_on_obj(s, SE_RN_NOT_SUPPORTED, 0, DON(ast), MB_FUNC_ERR, _exit, result);
+
+		break;
+	}
+
+_exit:
+	return result;
+}
+
 int _std_print(mb_interpreter_t* s, void** l) {
 	/* PRINT statement */
 	int result = MB_FUNC_OK;

resource/my_basic.rc

@@ -36,8 +36,8 @@
 	IDI_ICON_MAIN ICON "icon.ico"
 
 	VS_VERSION_INFO VERSIONINFO
-	FILEVERSION 1,1,72,0
+	FILEVERSION 1,1,73,0
-	PRODUCTVERSION 1,1,72,0
+	PRODUCTVERSION 1,1,73,0
 	FILEFLAGSMASK 0x17L
 #	ifdef _DEBUG
 	FILEFLAGS 0x1L
@@ -55,13 +55,13 @@
 				VALUE "Comments", "MY-BASIC"
 				VALUE "CompanyName", "Wang Renxin"
 				VALUE "FileDescription", "MY-BASIC Interpreter for Windows"
-				VALUE "FileVersion", "1, 1, 72, 0"
+				VALUE "FileVersion", "1, 1, 73, 0"
 				VALUE "InternalName", "my_basic"
 				VALUE "LegalCopyright", "Copyright (C) 2011 - 2015 Wang Renxin"
 				VALUE "LegalTrademarks", "MY-BASIC"
 				VALUE "OriginalFilename", "my_basic.exe"
 				VALUE "ProductName", "MY-BASIC"
-				VALUE "ProductVersion", "1, 1, 72, 0"
+				VALUE "ProductVersion", "1, 1, 73, 0"
 			END
 		END
 		BLOCK "VarFileInfo"

shell/main.c

@@ -40,6 +40,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <stdarg.h>
 
 #ifdef _MSC_VER
 #	pragma warning(disable : 4127)
@@ -84,6 +85,17 @@ static struct mb_interpreter_t* bas = 0;
 
 /* ========================================================} */
 
+/*
+ ** {========================================================
+ ** Common
+ */
+
+#ifndef _printf
+#	define _printf printf
+#endif /* _printf */
+
+/* ========================================================} */
+
 /*
  ** {========================================================
  ** Memory manipulation
@@ -426,18 +438,18 @@ static void _list_program(const char* sn, const char* cn) {
 	if(lsn == 0 && lcn == 0) {
 		long i = 0;
 		for(i = 0; i < c->count; ++i) {
-			printf("%ld]%s", i + 1, c->lines[i]);
+			_printf("%ld]%s", i + 1, c->lines[i]);
 		}
 	} else {
 		long i = 0;
 		long e = 0;
 		if(lsn < 1 || lsn > c->count) {
-			printf("Line number %ld out of bound.\n", lsn);
+			_printf("Line number %ld out of bound.\n", lsn);
 
 			return;
 		}
 		if(lcn < 0) {
-			printf("Invalid line count %ld.\n", lcn);
+			_printf("Invalid line count %ld.\n", lcn);
 
 			return;
 		}
@@ -447,7 +459,7 @@ static void _list_program(const char* sn, const char* cn) {
 			if(i >= c->count)
 				break;
 
-			printf("%ld]%s\n", i + 1, c->lines[i]);
+			_printf("%ld]%s\n", i + 1, c->lines[i]);
 		}
 	}
 }
@@ -461,13 +473,13 @@ static void _edit_program(const char* no) {
 
 	lno = atoi(no);
 	if(lno < 1 || lno > c->count) {
-		printf("Line number %ld out of bound.\n", lno);
+		_printf("Line number %ld out of bound.\n", lno);
 
 		return;
 	}
 	--lno;
 	memset(line, 0, _MAX_LINE_LENGTH);
-	printf("%ld]", lno + 1);
+	_printf("%ld]", lno + 1);
 	mb_gets(line, _MAX_LINE_LENGTH);
 	l = (int)strlen(line);
 	c->lines[lno] = (char*)realloc(c->lines[lno], l + 2);
@@ -485,13 +497,13 @@ static void _insert_program(const char* no) {
 
 	lno = atoi(no);
 	if(lno < 1 || lno > c->count) {
-		printf("Line number %ld out of bound.\n", lno);
+		_printf("Line number %ld out of bound.\n", lno);
 
 		return;
 	}
 	--lno;
 	memset(line, 0, _MAX_LINE_LENGTH);
-	printf("%ld]", lno + 1);
+	_printf("%ld]", lno + 1);
 	mb_gets(line, _MAX_LINE_LENGTH);
 	if(c->count + 1 == c->size) {
 		c->size += _LINE_INC_STEP;
@@ -512,7 +524,7 @@ static void _alter_program(const char* no) {
 
 	lno = atoi(no);
 	if(lno < 1 || lno > c->count) {
-		printf("Line number %ld out of bound.\n", lno);
+		_printf("Line number %ld out of bound.\n", lno);
 
 		return;
 	}
@@ -530,24 +542,24 @@ static void _load_program(const char* path) {
 		_set_code(c, txt);
 		free(txt);
 		if(c->count == 1) {
-			printf("Load done. %d line loaded.\n", c->count);
+			_printf("Load done. %d line loaded.\n", c->count);
 		} else {
-			printf("Load done. %d lines loaded.\n", c->count);
+			_printf("Load done. %d lines loaded.\n", c->count);
 		}
 	} else {
-		printf("Cannot load file \"%s\".\n", path);
+		_printf("Cannot load file \"%s\".\n", path);
 	}
 }
 
 static void _save_program(const char* path) {
 	char* txt = _get_code(c);
 	if(!_save_file(path, txt)) {
-		printf("Cannot save file \"%s\".\n", path);
+		_printf("Cannot save file \"%s\".\n", path);
 	} else {
 		if(c->count == 1) {
-			printf("Save done. %d line saved.\n", c->count);
+			_printf("Save done. %d line saved.\n", c->count);
 		} else {
-			printf("Save done. %d lines saved.\n", c->count);
+			_printf("Save done. %d lines saved.\n", c->count);
 		}
 	}
 	free(txt);
@@ -555,41 +567,41 @@ static void _save_program(const char* path) {
 
 static void _kill_program(const char* path) {
 	if(!unlink(path)) {
-		printf("Delete file \"%s\" successfully.\n", path);
+		_printf("Delete file \"%s\" successfully.\n", path);
 	} else {
-		printf("Delete file \"%s\" failed.\n", path);
+		_printf("Delete file \"%s\" failed.\n", path);
 	}
 }
 
 static void _show_tip(void) {
-	printf("MY-BASIC Interpreter Shell - %s.\n", mb_ver_string());
+	_printf("MY-BASIC Interpreter Shell - %s.\n", mb_ver_string());
-	printf("Copyright (C) 2011 - 2015 Wang Renxin. All Rights Reserved.\n");
+	_printf("Copyright (C) 2011 - 2015 Wang Renxin. All Rights Reserved.\n");
-	printf("For more information, see https://github.com/paladin-t/my_basic/.\n");
+	_printf("For more information, see https://github.com/paladin-t/my_basic/.\n");
-	printf("Input HELP and hint enter to view help information.\n");
+	_printf("Input HELP and hint enter to view help information.\n");
 }
 
 static void _show_help(void) {
-	printf("Parameters:\n");
+	_printf("Parameters:\n");
-	printf("  %s - Start interactive mode without arguments.\n", _BIN_FILE_NAME);
+	_printf("  %s - Start interactive mode without arguments.\n", _BIN_FILE_NAME);
-	printf("  %s *.* - Load and run a file.\n", _BIN_FILE_NAME);
+	_printf("  %s *.* - Load and run a file.\n", _BIN_FILE_NAME);
-	printf("  %s -e \"expr\" - Evaluate an expression directly.\n", _BIN_FILE_NAME);
+	_printf("  %s -e \"expr\" - Evaluate an expression directly.\n", _BIN_FILE_NAME);
-	printf("Interactive commands:\n");
+	_printf("Interactive commands:\n");
-	printf("  CLS   - Clear screen\n");
+	_printf("  CLS   - Clear screen\n");
-	printf("  NEW   - Clear current program\n");
+	_printf("  NEW   - Clear current program\n");
-	printf("  RUN   - Run current program\n");
+	_printf("  RUN   - Run current program\n");
-	printf("  BYE   - Quit interpreter\n");
+	_printf("  BYE   - Quit interpreter\n");
-	printf("  LIST  - List current program\n");
+	_printf("  LIST  - List current program\n");
-	printf("          Usage: LIST [l [n]], l is start line number, n is line count\n");
+	_printf("          Usage: LIST [l [n]], l is start line number, n is line count\n");
-	printf("  EDIT  - Edit (modify/insert/remove) a line in current program\n");
+	_printf("  EDIT  - Edit (modify/insert/remove) a line in current program\n");
-	printf("          Usage: EDIT n, n is line number\n");
+	_printf("          Usage: EDIT n, n is line number\n");
-	printf("                 EDIT -I n, insert a line before a given line, n is line number\n");
+	_printf("                 EDIT -I n, insert a line before a given line, n is line number\n");
-	printf("                 EDIT -R n, remove a line, n is line number\n");
+	_printf("                 EDIT -R n, remove a line, n is line number\n");
-	printf("  LOAD  - Load a file as current program\n");
+	_printf("  LOAD  - Load a file as current program\n");
-	printf("          Usage: LOAD *.*\n");
+	_printf("          Usage: LOAD *.*\n");
-	printf("  SAVE  - Save current program to a file\n");
+	_printf("  SAVE  - Save current program to a file\n");
-	printf("          Usage: SAVE *.*\n");
+	_printf("          Usage: SAVE *.*\n");
-	printf("  KILL  - Delete a file\n");
+	_printf("  KILL  - Delete a file\n");
-	printf("          Usage: KILL *.*\n");
+	_printf("          Usage: KILL *.*\n");
 }
 
 static int _do_line(void) {
@@ -600,7 +612,7 @@ static int _do_line(void) {
 	mb_assert(bas);
 
 	memset(line, 0, _MAX_LINE_LENGTH);
-	printf("]");
+	_printf("]");
 	mb_gets(line, _MAX_LINE_LENGTH);
 
 	memcpy(dup, line, _MAX_LINE_LENGTH);
@@ -621,7 +633,7 @@ static int _do_line(void) {
 		for(i = 0; i < c->count; ++i)
 			mb_load_string(bas, c->lines[i]);
 		result = mb_run(bas);
-		printf("\n");
+		_printf("\n");
 	} else if(_str_eq(line, "BYE")) {
 		result = MB_FUNC_BYE;
 	} else if(_str_eq(line, "LIST")) {
@@ -667,7 +679,7 @@ static int _do_line(void) {
 #define _CHECK_ARG(__c, __i, __e) \
 do { \
 	if(__c <= __i + 1) { \
-			printf(__e); \
+		_printf(__e); \
 		return; \
 	} \
 } while(0)
@@ -676,7 +688,7 @@ static void _run_file(char* path) {
 	if(mb_load_file(bas, path) == MB_FUNC_OK) {
 		mb_run(bas);
 	} else {
-		printf("Invalid file or error code.\n");
+		_printf("Invalid file or error code.\n");
 	}
 }
 
@@ -690,7 +702,7 @@ static void _evaluate_expression(char* p) {
 	const char* const print = "PRINT ";
 
 	if(!p) {
-		printf("Invalid expression.\n");
+		_printf("Invalid expression.\n");
 
 		return;
 	}
@@ -713,7 +725,7 @@ static void _evaluate_expression(char* p) {
 	if(mb_load_string(bas, p) == MB_FUNC_OK) {
 		mb_run(bas);
 	} else {
-		printf("Invalid expression.\n");
+		_printf("Invalid expression.\n");
 	}
 	if(a) {
 		free(e);
@@ -732,7 +744,7 @@ static void _process_parameters(int argc, char* argv[]) {
 				_CHECK_ARG(argc, i, "-e: Expression expected.\n");
 				p = argv[++i];
 			} else {
-				printf("Unknown argument: %s.\n", argv[i]);
+				_printf("Unknown argument: %s.\n", argv[i]);
 			}
 		} else {
 			p = argv[i];
@@ -790,7 +802,7 @@ static void _on_error(struct mb_interpreter_t* s, mb_error_e e, char* m, char* f
 	mb_unrefvar(f);
 	mb_unrefvar(p);
 	if(SE_NO_ERR != e) {
-		printf("Error:\n    [LINE] %d, [COL] %d,\n    [CODE] %d, [MESSAGE] %s, [ABORT CODE] %d.\n", row, col, e, m, abort_code);
+		_printf("Error:\n    [LINE] %d, [COL] %d,\n    [CODE] %d, [MESSAGE] %s, [ABORT CODE] %d.\n", row, col, e, m, abort_code);
 	}
 }
 
@@ -862,7 +874,7 @@ int main(int argc, char* argv[]) {
 	} else if(argc >= 2) {
 		_process_parameters(argc, argv);
 	} else {
-		printf("Unknown arguments.\n");
+		_printf("Unknown arguments.\n");
 		_show_tip();
 	}