allow local NPC functions to be public or private

5 files changed, 423 insertions, 159 deletions

diff --git a/src/map/map.h b/src/map/map.h
index 2de6df2f7..b3cdef025 100644
--- a/src/map/map.h
+++ b/src/map/map.h
@@ -329,6 +329,14 @@ enum bl_type {
 
 enum npc_subtype { WARP, SHOP, SCRIPT, CASHSHOP, TOMB };
 
+/** optional flags for script labels, used by the label db */
+enum script_label_flags {
+	/** the label can be called from outside the local scope of the NPC */
+	LABEL_IS_EXTERN   = 0x1,
+	/** the label is a public or private local NPC function */
+	LABEL_IS_USERFUNC = 0x2,
+};
+
 /**
  * Race type IDs.
  *
diff --git a/src/map/npc.c b/src/map/npc.c
index 40ec380ee..570305ba1 100644
--- a/src/map/npc.c
+++ b/src/map/npc.c
@@ -389,7 +389,8 @@ static int npc_event_export(struct npc_data *nd, int i)
 	Assert_ret(i >= 0 && i < nd->u.scr.label_list_num);
 	lname = nd->u.scr.label_list[i].name;
 	pos = nd->u.scr.label_list[i].pos;
-	if ((lname[0] == 'O' || lname[0] == 'o') && (lname[1] == 'N' || lname[1] == 'n')) {
+
+	if ((nd->u.scr.label_list[i].flags & LABEL_IS_EXTERN) != 0 && (nd->u.scr.label_list[i].flags & LABEL_IS_USERFUNC) == 0) {
 		struct event_data *ev;
 		struct linkdb_node **label_linkdb = NULL;
 		char buf[EVENT_NAME_LENGTH];
@@ -3054,11 +3055,11 @@ static int npc_unload(struct npc_data *nd, bool single, bool unload_mobs)
 		aFree(nd->u.shop.shop_item); /// src check for duplicate shops. [Orcao]
 	} else if (nd->subtype == SCRIPT) {
 		char evname[EVENT_NAME_LENGTH];
-		
+
 		snprintf(evname, ARRAYLENGTH(evname), "%s::OnNPCUnload", nd->exname);
 
 		struct event_data *ev = strdb_get(npc->ev_db, evname);
-		
+
 		if (ev != NULL)
 			script->run_npc(nd->u.scr.script, ev->pos, 0, nd->bl.id); /// Run OnNPCUnload.
 
@@ -3665,6 +3666,7 @@ static void npc_convertlabel_db(struct npc_label_list *label_list, const char *f
 	for( i = 0; i < script->label_count; i++ ) {
 		const char* lname = script->get_str(script->labels[i].key);
 		int lpos = script->labels[i].pos;
+		enum script_label_flags flags = script->labels[i].flags;
 		struct npc_label_list* label;
 		const char *p;
 		size_t len;
@@ -3686,6 +3688,7 @@ static void npc_convertlabel_db(struct npc_label_list *label_list, const char *f
 
 		safestrncpy(label->name, lname, sizeof(label->name));
 		label->pos = lpos;
+		label->flags = flags;
 	}
 }
 
@@ -5606,7 +5609,7 @@ static int npc_reload(void)
 	npc->npc_last_npd = NULL;
 	npc->npc_last_path = NULL;
 	npc->npc_last_ref = NULL;
-	
+
 	const int npc_new_min = npc->npc_id;
 	struct s_mapiterator *iter = mapit_geteachiddb();
 
diff --git a/src/map/npc.h b/src/map/npc.h
index 1585a2bc8..a73a3ae06 100644
--- a/src/map/npc.h
+++ b/src/map/npc.h
@@ -59,6 +59,7 @@ struct npc_timerevent_list {
 struct npc_label_list {
 	char name[NAME_LENGTH];
 	int pos;
+	enum script_label_flags flags;
 };
 
 struct npc_barter_currency {
diff --git a/src/map/script.c b/src/map/script.c
index c08f5e829..9d6b9d8a2 100644
--- a/src/map/script.c
+++ b/src/map/script.c
@@ -848,79 +848,134 @@ static const char *parse_callfunc(const char *p, int require_paren, int is_custo
 
 	nullpo_retr(NULL, p);
 	// is need add check for arg null pointer below?
-	func = script->add_word(p);
-	if (script->str_data[func].type == C_FUNC) {
-		script->syntax.nested_call++;
-		if (script->syntax.last_func != -1) {
-			if (script->str_data[func].val == script->buildin_lang_macro_offset) {
-				script->syntax.lang_macro_active = true;
-				macro = true;
-			} else if (script->str_data[func].val == script->buildin_lang_macro_fmtstring_offset) {
-				script->syntax.lang_macro_fmtstring_active = true;
-				macro = true;
-			}
+
+	if (*p == '"') {
+		p2 = ++p; // jump to the start of the word
+
+		// find the closing quote
+		while (*p2 != '"') {
+			++p2;
 		}
 
-		if( !macro ) {
-			// buildin function
+		if (p2[1] == ':' && p2[2] == ':') {
+			func = script->add_str("callfunctionofnpc");
+			arg = "*"; // we already take care of the "vs" part of "vs*"
+
+			script->syntax.nested_call++;
 			script->syntax.last_func = script->str_data[func].val;
 			script->addl(func);
 			script->addc(C_ARG);
-		}
 
-		arg = script->buildin[script->str_data[func].val];
-		if (script->str_data[func].deprecated)
-			DeprecationWarning(p);
-		if( !arg ) arg = &null_arg; // Use a dummy, null string
-	} else if( script->str_data[func].type == C_USERFUNC || script->str_data[func].type == C_USERFUNC_POS ) {
-		// script defined function
-		script->addl(script->buildin_callsub_ref);
-		script->addc(C_ARG);
-		script->addl(func);
-		arg = script->buildin[script->str_data[script->buildin_callsub_ref].val];
-		if( *arg == 0 )
-			disp_error_message("parse_callfunc: callsub has no arguments, please review its definition",p);
-		if( *arg != '*' )
-			++arg; // count func as argument
+			script->addc(C_STR);
+			do {
+				script->addb(*p++); // npc name
+			} while (p < p2);
+			script->addb(0);
+
+			p = p2 + 3; // skip to start of func name
+			p2 = script->skip_word(p);
+
+			script->addc(C_STR);
+			do {
+				script->addb(*p++); // func name
+			} while (p < p2);
+			script->addb(0);
+
+			p = p2; // skip to just before the ()
+		} else {
+			disp_error_message("script:parse_callfunc: invalid public function call syntax!", p2 + 1);
+		}
 	} else {
+		func = script->add_word(p);
+		if (script->str_data[func].type == C_FUNC) {
+			script->syntax.nested_call++;
+
+			if (script->syntax.last_func != -1) {
+				if (script->str_data[func].val == script->buildin_lang_macro_offset) {
+					script->syntax.lang_macro_active = true;
+					macro = true;
+				} else if (script->str_data[func].val == script->buildin_lang_macro_fmtstring_offset) {
+					script->syntax.lang_macro_fmtstring_active = true;
+					macro = true;
+				}
+			}
+
+			if (!macro) {
+				// buildin function
+				script->syntax.last_func = script->str_data[func].val;
+				script->addl(func);
+				script->addc(C_ARG);
+			}
+
+			arg = script->buildin[script->str_data[func].val];
+
+			if (script->str_data[func].deprecated == 1) {
+				DeprecationWarning(p);
+			}
+
+			if (arg == NULL) {
+				arg = &null_arg; // Use a dummy, null string
+			}
+		} else if (script->str_data[func].type == C_USERFUNC || script->str_data[func].type == C_USERFUNC_POS) {
+			// script defined function
+			script->addl(script->buildin_callsub_ref);
+			script->addc(C_ARG);
+			script->addl(func);
+			arg = script->buildin[script->str_data[script->buildin_callsub_ref].val];
+
+			if (*arg == 0) {
+				disp_error_message("script:parse_callfunc: callsub has no arguments, please review its definition", p);
+			}
+
+			if (*arg != '*') {
+				++arg; // count func as argument
+			}
+		} else {
 #ifdef SCRIPT_CALLFUNC_CHECK
-		const char* name = script->get_str(func);
-		if( !is_custom && strdb_get(script->userfunc_db, name) == NULL ) {
+			const char *name = script->get_str(func);
+			if (is_custom == 0 && strdb_get(script->userfunc_db, name) == NULL) {
 #endif
-			disp_error_message("parse_line: expect command, missing function name or calling undeclared function",p);
+				disp_error_message("script:parse_callfunc: expect command, missing function name or calling undeclared function", p);
 #ifdef SCRIPT_CALLFUNC_CHECK
-		} else {;
-			script->addl(script->buildin_callfunc_ref);
-			script->addc(C_ARG);
-			script->addc(C_STR);
-			while( *name ) script->addb(*name ++);
-			script->addb(0);
-			arg = script->buildin[script->str_data[script->buildin_callfunc_ref].val];
-			if( *arg != '*' ) ++ arg;
-		}
+			} else {
+				script->addl(script->buildin_callfunc_ref);
+				script->addc(C_ARG);
+				script->addc(C_STR);
+
+				while (*name != '\0') {
+					script->addb(*name++);
+				}
+
+				script->addb(0);
+				arg = script->buildin[script->str_data[script->buildin_callfunc_ref].val];
+
+				if (*arg != '*') {
+					++ arg;
+				}
+			}
 #endif
+		}
 	}
 
 	p = script->skip_word(p);
 	p = script->skip_space(p);
 	script->syntax.curly[script->syntax.curly_count].type = TYPE_ARGLIST;
 	script->syntax.curly[script->syntax.curly_count].count = 0;
-	if( *p == ';' )
-	{// <func name> ';'
+
+	if (*p == ';') {
+		// <func name> ';'
 		script->syntax.curly[script->syntax.curly_count].flag = ARGLIST_NO_PAREN;
-	} else if( *p == '(' && *(p2=script->skip_space(p+1)) == ')' )
-	{// <func name> '(' ')'
+	} else if (*p == '(' && *(p2 = script->skip_space(p + 1)) == ')') {
+		// <func name> '(' ')'
 		script->syntax.curly[script->syntax.curly_count].flag = ARGLIST_PAREN;
 		p = p2;
-	/*
-	} else if( 0 && require_paren && *p != '(' )
-	{// <func name>
-		script->syntax.curly[script->syntax.curly_count].flag = ARGLIST_NO_PAREN;
-	*/
-	} else {// <func name> <arg list>
-		if( require_paren ) {
-			if( *p != '(' )
-				disp_error_message("need '('",p);
+	} else {
+		// <func name> <arg list>
+		if (require_paren == 1) {
+			if (*p != '(') {
+				disp_error_message("script:parse_callfunc: need '('", p);
+			}
+
 			++p; // skip '('
 			script->syntax.curly[script->syntax.curly_count].flag = ARGLIST_PAREN;
 		} else if( *p == '(' ) {
@@ -928,41 +983,65 @@ static const char *parse_callfunc(const char *p, int require_paren, int is_custo
 		} else {
 			script->syntax.curly[script->syntax.curly_count].flag = ARGLIST_NO_PAREN;
 		}
+
 		++script->syntax.curly_count;
-		while( *arg ) {
-			p2=script->parse_subexpr(p,-1);
-			if( p == p2 )
-				break; // not an argument
-			if( *arg != '*' )
-				++arg; // next argument
 
-			p=script->skip_space(p2);
-			if( *arg == 0 || *p != ',' )
-				break; // no more arguments
+		while (*arg != '\0') {
+			p2 = script->parse_subexpr(p, -1);
+
+			if (p == p2) {
+				// not an argument
+				break;
+			}
+
+			if (*arg != '*') {
+				// next argument
+				++arg;
+			}
+
+			p = script->skip_space(p2);
+
+			if (*arg == 0 || *p != ',') {
+				// no more arguments
+				break;
+			}
+
 			++p; // skip comma
 		}
+
 		--script->syntax.curly_count;
 	}
-	if( arg && *arg && *arg != '?' && *arg != '*' )
-		disp_error_message2("parse_callfunc: not enough arguments, expected ','", p, script->config.warn_func_mismatch_paramnum);
-	if( script->syntax.curly[script->syntax.curly_count].type != TYPE_ARGLIST )
-		disp_error_message("parse_callfunc: DEBUG last curly is not an argument list",p);
-	if( script->syntax.curly[script->syntax.curly_count].flag == ARGLIST_PAREN ) {
-		if( *p != ')' )
-			disp_error_message("parse_callfunc: expected ')' to close argument list",p);
+
+	if (arg != NULL && *arg != '\0' && *arg != '?' && *arg != '*') {
+		disp_error_message2("script:parse_callfunc: not enough arguments, expected ','", p, script->config.warn_func_mismatch_paramnum);
+	}
+
+	if (script->syntax.curly[script->syntax.curly_count].type != TYPE_ARGLIST) {
+		disp_error_message("parse_callfunc: DEBUG last curly is not an argument list", p);
+	}
+
+	if (script->syntax.curly[script->syntax.curly_count].flag == ARGLIST_PAREN) {
+		if (*p != ')') {
+			disp_error_message("script:parse_callfunc: expected ')' to close argument list", p);
+		}
+
 		++p;
 
-		if (script->str_data[func].val == script->buildin_lang_macro_offset)
+		if (script->str_data[func].val == script->buildin_lang_macro_offset) {
 			script->syntax.lang_macro_active = false;
-		else if (script->str_data[func].val == script->buildin_lang_macro_fmtstring_offset)
+		} else if (script->str_data[func].val == script->buildin_lang_macro_fmtstring_offset) {
 			script->syntax.lang_macro_fmtstring_active = false;
+		}
 	}
 
 	if (!macro) {
-		if (0 == --script->syntax.nested_call)
+		if (0 == --script->syntax.nested_call) {
 			script->syntax.last_func = -1;
+		}
+
 		script->addc(C_FUNC);
 	}
+
 	return p;
 }
 
@@ -1230,16 +1309,29 @@ static int script_string_dup(char *str)
  *------------------------------------------*/
 static const char *parse_simpleexpr(const char *p)
 {
-	p=script->skip_space(p);
+	p = script->skip_space(p);
 
 	nullpo_retr(NULL, p);
-	if (*p == ';' || *p == ',')
-		disp_error_message("parse_simpleexpr: unexpected end of expression",p);
+
+	if (*p == ';' || *p == ',') {
+		disp_error_message("script:parse_simpleexpr: unexpected end of expression", p);
+	}
+
 	if (*p == '(') {
 		return script->parse_simpleexpr_paren(p);
 	} else if (is_number(p)) {
 		return script->parse_simpleexpr_number(p);
 	} else if(*p == '"') {
+		const char *p2 = p + 1;
+
+		while (*p2 != '"') {
+			++p2;
+		}
+
+		if (p2[1] == ':' && p2[2] == ':') {
+			return script->parse_callfunc(p, 1, 0); // XXX: why does callfunc use int for booleans?
+		}
+
 		return script->parse_simpleexpr_string(p);
 	} else {
 		return script->parse_simpleexpr_name(p);
@@ -1577,6 +1669,85 @@ static const char *parse_line(const char *p)
 	return p;
 }
 
+/**
+ * parses a local function expression
+ *
+ * expects these formats:
+ *     function <name>;
+ *     function <name> { <script> }
+ *
+ * this is invoked by script->parse_syntax() after checking whether the function
+ * is public or not
+ *
+ * @param p - a pointer to the start of the function expression
+ * @param is_public - whether this function should be accessible from outside the NPC scope
+ */
+static const char *parse_syntax_function (const char *p, bool is_public)
+{
+	const char *func_name = script->skip_space(p); // the name of the local function
+	p = script->skip_word(func_name);
+
+	if (p == func_name) {
+		disp_error_message("script:parse_syntax_function: function name is missing or invalid", p);
+	}
+
+	const char *p2 = script->skip_space(p);
+
+	if (*p2 == ';') {
+		// function <name> ;
+		// function declaration - just register the name
+		int l = script->add_word(func_name);
+
+		if (script->str_data[l].type == C_NOP) {
+			// register only, if the name was not used by something else
+			script->str_data[l].type = C_USERFUNC;
+		} else if (script->str_data[l].type != C_USERFUNC) {
+			disp_error_message("script:parse_syntax_function: function name is already in use", func_name);
+		}
+
+		// Close condition of if, for, while
+		p = script->parse_syntax_close(p2 + 1);
+		return p;
+	} else if (*p2 == '{') {
+		// function <name> <line/block of code>
+		script->syntax.curly[script->syntax.curly_count].type  = TYPE_USERFUNC;
+		script->syntax.curly[script->syntax.curly_count].count = 1;
+		script->syntax.curly[script->syntax.curly_count].index = script->syntax.index++;
+		script->syntax.curly[script->syntax.curly_count].flag  = 0;
+		++script->syntax.curly_count;
+
+		// Jump over the function code
+		char label[256];
+		sprintf(label, "goto __FN%x_FIN;", (unsigned int)script->syntax.curly[script->syntax.curly_count - 1].index);
+		script->syntax.curly[script->syntax.curly_count].type = TYPE_NULL;
+		++script->syntax.curly_count;
+		script->parse_line(label);
+		--script->syntax.curly_count;
+
+		// Set the position of the function (label)
+		int l = script->add_word(func_name);
+
+		if (script->str_data[l].type == C_NOP || script->str_data[l].type == C_USERFUNC) {
+			// register only, if the name was not used by something else
+			script->str_data[l].type = C_USERFUNC;
+			script->set_label(l, VECTOR_LENGTH(script->buf), p);
+
+			if ((script->parse_options & SCRIPT_USE_LABEL_DB) != 0) {
+				script->label_add(l, VECTOR_LENGTH(script->buf),
+					LABEL_IS_USERFUNC | (is_public ? LABEL_IS_EXTERN : 0));
+			}
+		} else {
+			disp_error_message("script:parse_syntax_function: function name is already in use", func_name);
+		}
+
+		return script->skip_space(p);
+	} else {
+		disp_error_message("script:parse_syntax_function: expected ';' or '{' at function syntax", p);
+	}
+
+	return p;
+}
+
 // { ... } Closing process
 static const char *parse_curly_close(const char *p)
 {
@@ -1920,66 +2091,8 @@ static const char *parse_syntax(const char *p)
 			script->set_label(l, VECTOR_LENGTH(script->buf), p);
 			return p;
 		} else if( p2 - p == 8 && strncmp(p, "function", 8) == 0 ) {
-			// internal script function
-			const char *func_name;
-
-			func_name = script->skip_space(p2);
-			p = script->skip_word(func_name);
-			if( p == func_name )
-				disp_error_message("parse_syntax:function: function name is missing or invalid", p);
-			p2 = script->skip_space(p);
-			if( *p2 == ';' )
-			{// function <name> ;
-				// function declaration - just register the name
-				int l;
-				l = script->add_word(func_name);
-				if( script->str_data[l].type == C_NOP )// register only, if the name was not used by something else
-					script->str_data[l].type = C_USERFUNC;
-				else if( script->str_data[l].type == C_USERFUNC )
-					;  // already registered
-				else
-					disp_error_message("parse_syntax:function: function name is invalid", func_name);
-
-				// Close condition of if, for, while
-				p = script->parse_syntax_close(p2 + 1);
-				return p;
-			}
-			else if(*p2 == '{')
-			{// function <name> <line/block of code>
-				char label[256];
-				int l;
-
-				script->syntax.curly[script->syntax.curly_count].type  = TYPE_USERFUNC;
-				script->syntax.curly[script->syntax.curly_count].count = 1;
-				script->syntax.curly[script->syntax.curly_count].index = script->syntax.index++;
-				script->syntax.curly[script->syntax.curly_count].flag  = 0;
-				++script->syntax.curly_count;
-
-				// Jump over the function code
-				sprintf(label, "goto __FN%x_FIN;", (unsigned int)script->syntax.curly[script->syntax.curly_count-1].index);
-				script->syntax.curly[script->syntax.curly_count].type = TYPE_NULL;
-				++script->syntax.curly_count;
-				script->parse_line(label);
-				--script->syntax.curly_count;
-
-				// Set the position of the function (label)
-				l=script->add_word(func_name);
-				if( script->str_data[l].type == C_NOP || script->str_data[l].type == C_USERFUNC )// register only, if the name was not used by something else
-				{
-					script->str_data[l].type = C_USERFUNC;
-					script->set_label(l, VECTOR_LENGTH(script->buf), p);
-					if( script->parse_options&SCRIPT_USE_LABEL_DB )
-						script->label_add(l, VECTOR_LENGTH(script->buf));
-				}
-				else
-					disp_error_message("parse_syntax:function: function name is invalid", func_name);
-
-				return script->skip_space(p);
-			}
-			else
-			{
-				disp_error_message("expect ';' or '{' at function syntax",p);
-			}
+			// local function implicitly marked as private
+			return script->parse_syntax_function(p2, false);
 		}
 		break;
 	case 'i':
@@ -2006,6 +2119,26 @@ static const char *parse_syntax(const char *p)
 			return p;
 		}
 		break;
+	case 'p':
+	case 'P':
+		if (p2 - p == 6 && strncmp(p, "public", 6) == 0) {
+			p2 = script->skip_space(p2);
+			const char *p3 = script->skip_word(p2);
+
+			if (p3 - p2 == 8 && strncmp(p2, "function", 8) == 0) {
+				// local function explicitly marked as public
+				return script->parse_syntax_function(p3, true);
+			}
+		} else if (p2 - p == 7 && strncmp(p, "private", 7) == 0) {
+			p2 = script->skip_space(p2);
+			const char *p3 = script->skip_word(p2);
+
+			if (p3 - p2 == 8 && strncmp(p2, "function", 8) == 0) {
+				// local function explicitly marked as private
+				return script->parse_syntax_function(p3, false);
+			}
+		}
+		break;
 	case 's':
 	case 'S':
 		if( p2 - p == 6 && strncmp(p, "switch", 6) == 0 ) {
@@ -2668,25 +2801,32 @@ static struct script_code *parse_script(const char *src, const char *file, int l
 		}
 	}
 
-	while( script->syntax.curly_count != 0 || *p != end )
-	{
-		if( *p == '\0' )
-			disp_error_message("unexpected end of script",p);
+	while (script->syntax.curly_count != 0 || *p != end) {
+		if (*p == '\0') {
+			disp_error_message("script:parse_script: unexpected end of script", p);
+		}
+
 		// Special handling only label
-		tmpp=script->skip_space(script->skip_word(p));
-		if(*tmpp==':' && !(strncmp(p,"default:",8) == 0 && p + 7 == tmpp)) {
-			i=script->add_word(p);
+		tmpp = script->skip_space(script->skip_word(p));
+
+		if (*tmpp == ':' && !(strncmp(p, "default:", 8) == 0 && p + 7 == tmpp)
+			&& !(strncmp(p, "function", 8) == 0 && script->skip_space(p + 8) == tmpp)) {
+			i = script->add_word(p);
 			script->set_label(i, VECTOR_LENGTH(script->buf), p);
-			if( script->parse_options&SCRIPT_USE_LABEL_DB )
-				script->label_add(i, VECTOR_LENGTH(script->buf));
-			p=tmpp+1;
-			p=script->skip_space(p);
+
+			if ((script->parse_options & SCRIPT_USE_LABEL_DB) != 0) {
+				bool is_extern = ((p[0] == 'O' || p[0] == 'o') && (p[1] == 'N' || p[1] == 'n'));
+				script->label_add(i, VECTOR_LENGTH(script->buf), is_extern ? LABEL_IS_EXTERN : 0);
+			}
+
+			p = tmpp + 1;
+			p = script->skip_space(p);
 			continue;
 		}
 
 		// All other lumped
-		p=script->parse_line(p);
-		p=script->skip_space(p);
+		p = script->parse_line(p);
+		p = script->skip_space(p);
 
 		script->parse_nextline(false, p);
 	}
@@ -6397,6 +6537,111 @@ static BUILDIN(callfunc)
 
 	return true;
 }
+
+/**
+ * Calls a local function within a NPC as if it was part of the current scope.
+ * Resumes execution in the previous scope once the NPC function returns. This
+ * is essentially a clone of buildin_callsub that can run in arbitrary NPCs.
+ *
+ * Usage:
+ *     callfunctionofnpc("<npc name>", "<function name>"{, <arg>...})
+ *     callfunctionofnpc(<npc id>, "<function name>"{, <arg>...})
+ *
+ * This buildin is also used internally by this syntax:
+ *     "<npc name>"::<function name>({<arg>...})
+ */
+static BUILDIN(callfunctionofnpc) {
+	struct npc_data *nd = NULL;
+
+	if (script_isstring(st, 2)) {
+		nd = npc->name2id(script_getstr(st, 2));
+	} else {
+		nd = map->id2nd(script_getnum(st, 2));
+	}
+
+	if (nd == NULL) {
+		ShowError("script:callfunctionofnpc: NPC not found.\n");
+		st->state = END;
+		return false;
+	}
+
+	const char *function_name = script_getstr(st, 3);
+	int pos = -1;
+
+	// find the function label within the label list of the NPC
+	for (int i = 0; i < nd->u.scr.label_list_num; ++i) {
+		if (strcmp(nd->u.scr.label_list[i].name, function_name) == 0) {
+			if ((nd->u.scr.label_list[i].flags & LABEL_IS_EXTERN) != 0
+				&& (nd->u.scr.label_list[i].flags & LABEL_IS_USERFUNC) != 0) {
+				// function label found: set the start location
+				pos = nd->u.scr.label_list[i].pos;
+			} else if ((nd->u.scr.label_list[i].flags & LABEL_IS_USERFUNC) != 0) {
+				ShowError("script:callfunctionofnpc: function '%s' is not marked as public in NPC '%s'.\n", function_name, nd->name);
+				st->state = END;
+				return false;
+			}
+			break;
+		}
+	}
+
+	if (pos < 0) {
+		ShowError("script:callfunctionofnpc: function '%s' not found in NPC '%s'!\n", function_name, nd->name);
+		st->state = END;
+		return false;
+	}
+
+	// alloc a reg_db reference of the current scope for the new scope
+	struct reg_db *ref = (struct reg_db *)aCalloc(sizeof(struct reg_db), 2);
+	// scope variables (.@var)
+	ref[0].vars = st->stack->scope.vars;
+	ref[0].arrays = st->stack->scope.arrays;
+	// npc variables (.var)
+	ref[1].vars = st->script->local.vars;
+	ref[1].arrays = st->script->local.arrays;
+
+	int i = 0;
+
+	// make sure the arguments we push retain their current reg_db references:
+	// this allows to do things like set(getarg(0), ...)
+	for (i = st->start + 4; i < st->end; i++) {
+		struct script_data *data = script->push_copy(st->stack, i);
+
+		if (data_isreference(data) && data->ref == NULL) {
+			const char *name = reference_getname(data);
+
+			if (name[0] == '.') {
+				data->ref = (name[1] == '@' ? &ref[0] : &ref[1]);
+			}
+		}
+	}
+
+	// save the previous scope
+	struct script_retinfo *ri = NULL;
+	CREATE(ri, struct script_retinfo, 1);
+	ri->script       = st->script;              // script code
+	ri->scope.vars   = st->stack->scope.vars;   // scope variables
+	ri->scope.arrays = st->stack->scope.arrays; // scope arrays
+	ri->pos          = st->pos;                 // script location
+	ri->nargs        = i - st->start - 4;       // argument count
+	ri->defsp        = st->stack->defsp;        // default stack pointer
+	script->push_retinfo(st->stack, ri, ref);
+
+	// change the current scope to the scope of the function
+	st->pos = pos;
+	st->script = nd->u.scr.script;
+	st->stack->defsp = st->stack->sp;
+	st->state = GOTO;
+	st->stack->scope.vars = i64db_alloc(DB_OPT_RELEASE_DATA);
+	st->stack->scope.arrays = idb_alloc(DB_OPT_BASE);
+
+	// make sure local reg_db of the other NPC is initialized
+	if (st->script->local.vars == NULL) {
+		st->script->local.vars = i64db_alloc(DB_OPT_RELEASE_DATA);
+	}
+
+	return true;
+}
+
 /*==========================================
  * subroutine call
  *------------------------------------------*/
@@ -27390,6 +27635,8 @@ static void script_parse_builtin(void)
 		BUILDIN_DEF(identify, "i"),
 		BUILDIN_DEF(identifyidx, "i"),
 		BUILDIN_DEF(openlapineddukddakboxui, "i"),
+
+		BUILDIN_DEF(callfunctionofnpc, "vs*"),
 	};
 	int i, len = ARRAYLENGTH(BUILDIN);
 	RECREATE(script->buildin, char *, script->buildin_count + len); // Pre-alloc to speed up
@@ -27401,7 +27648,7 @@ static void script_parse_builtin(void)
 #undef BUILDIN_DEF
 #undef BUILDIN_DEF2
 
-static void script_label_add(int key, int pos)
+static void script_label_add(int key, int pos, enum script_label_flags flags)
 {
 	int idx = script->label_count;
 
@@ -27412,6 +27659,7 @@ static void script_label_add(int key, int pos)
 
 	script->labels[idx].key = key;
 	script->labels[idx].pos = pos;
+	script->labels[idx].flags = flags;
 	script->label_count++;
 }
 
@@ -28218,6 +28466,7 @@ void script_defaults(void)
 	script->parse_syntax_close = parse_syntax_close;
 	script->parse_syntax_close_sub = parse_syntax_close_sub;
 	script->parse_syntax = parse_syntax;
+	script->parse_syntax_function = parse_syntax_function;
 	script->get_com = get_com;
 	script->get_num = get_num;
 	script->op2name = script_op2name;
diff --git a/src/map/script.h b/src/map/script.h
index 511497a66..044bcdc42 100644
--- a/src/map/script.h
+++ b/src/map/script.h
@@ -726,7 +726,9 @@ struct str_data_struct {
 };
 
 struct script_label_entry {
-	int key,pos;
+	int key;
+	int pos;
+	enum script_label_flags flags;
 };
 
 struct script_syntax_data {
@@ -917,7 +919,7 @@ struct script_interface {
 	void (*set_constant) (const char *name, int value, bool is_parameter, bool is_deprecated);
 	void (*set_constant2) (const char *name, int value, bool is_parameter, bool is_deprecated);
 	bool (*get_constant) (const char* name, int* value);
-	void (*label_add)(int key, int pos);
+	void (*label_add)(int key, int pos, enum script_label_flags flags);
 	void (*run) (struct script_code *rootscript, int pos, int rid, int oid);
 	void (*run_npc) (struct script_code *rootscript, int pos, int rid, int oid);
 	void (*run_pet) (struct script_code *rootscript, int pos, int rid, int oid);
@@ -948,10 +950,11 @@ struct script_interface {
 	int (*queue_create) (void);
 	bool (*queue_clear) (int idx);
 	/* */
-	const char * (*parse_curly_close) (const char *p);
-	const char * (*parse_syntax_close) (const char *p);
-	const char * (*parse_syntax_close_sub) (const char *p, int *flag);
-	const char * (*parse_syntax) (const char *p);
+	const char *(*parse_curly_close) (const char *p);
+	const char *(*parse_syntax_close) (const char *p);
+	const char *(*parse_syntax_close_sub) (const char *p, int *flag);
+	const char *(*parse_syntax) (const char *p);
+	const char *(*parse_syntax_function) (const char *p, bool is_public);
 	c_op (*get_com) (const struct script_buf *scriptbuf, int *pos);
 	int (*get_num) (const struct script_buf *scriptbuf, int *pos);
 	const char* (*op2name) (int op);