diff --git a/libs/ruamoko/rua_string.c b/libs/ruamoko/rua_string.c
index a8240a85c..6de9c5c01 100644
--- a/libs/ruamoko/rua_string.c
+++ b/libs/ruamoko/rua_string.c
@@ -208,6 +208,45 @@ bi_str_char (progs_t *pr)
 	R_INT (pr) = str[ind];
 }
 
+static void
+bi_str_quote (progs_t *pr)
+{
+	const char *str = P_GSTRING (pr, 0);
+	// can have up to 4 chars per char (a -> \x61)
+	char       *quote = alloca (strlen (str) * 4 + 1);
+	char       *q = quote;
+	char        c;
+	int         h;
+
+	while ((c = *str++)) {
+		if (c >= ' ' && c < 127 && c != '\"') {
+			*q++ = c;
+		} else {
+			*q++ = '\\';
+			switch (c) {
+				case '\a': c = 'a'; break;
+				case '\b': c = 'b'; break;
+				case '\f': c = 'f'; break;
+				case '\n': c = 'n'; break;
+				case '\r': c = 'r'; break;
+				case '\t': c = 't'; break;
+				case '\"': c = '\"'; break;
+				default:
+					*q++ = 'x';
+					h = (c & 0xf0) >> 4;
+					*q++ = h > 9 ? h + 'a' - 10 : h + '0';
+					h = (c & 0x0f);
+					c = h > 9 ? h + 'a' - 10 : h + '0';
+					break;
+			}
+			*q++ = c;
+		}
+	}
+	*q++ = 0;
+
+	RETURN_STRING (pr, quote);
+}
+
 static builtin_t builtins[] = {
 	{"strlen",		bi_strlen,		-1},
 	{"sprintf",		bi_sprintf,		-1},
@@ -224,6 +263,7 @@ static builtin_t builtins[] = {
 	{"str_mid|*ii",	bi_str_mid,		-1},
 	{"str_str",		bi_str_str,		-1},
 	{"str_char",	bi_str_char,	-1},
+	{"str_quote",	bi_str_quote,	-1},
 	{0}
 };
 
diff --git a/ruamoko/include/string.h b/ruamoko/include/string.h
index b374b8335..008e7d883 100644
--- a/ruamoko/include/string.h
+++ b/ruamoko/include/string.h
@@ -16,5 +16,6 @@
 @extern @overload string str_mid (string str, int start, int len);
 @extern string str_str (string haystack, string needle);
 @extern int str_char (string str, int ind);
+string str_quote (string str);
 
 #endif//__ruamoko_string_h
diff --git a/ruamoko/lib/string.r b/ruamoko/lib/string.r
index 89ecc6aef..48a9a7bf7 100644
--- a/ruamoko/lib/string.r
+++ b/ruamoko/lib/string.r
@@ -15,3 +15,4 @@ string (string str, int start) str_mid = #0;
 string (string str, int start, int len) str_mid = #0;
 string (string haystack, string needle) str_str = #0;
 int str_char (string str, int ind) = #0;
+string str_quote (string str) = #0;