Support multiple elements \u syntax

mrbgems/mruby-compiler/core/parse.y

@@ -3995,6 +3995,20 @@ parse_string(parser_state *p)
           tokadd(p, '\\');
           tokadd(p, c);
         }
+        else if (c == 'u' && peek(p, '{')) {
+          /* \u{xxxx xxxx xxxx} form */
+          nextc(p);
+          while (1) {
+            do c = nextc(p); while (ISSPACE(c));
+            if (c == '}') break;
+            pushback(p, c);
+            c = read_escape_unicode(p, 8);
+            if (c < 0) break;
+            tokadd(p, -c);
+          }
+          if (hinf)
+            hinf->line_head = FALSE;
+        }
         else {
           pushback(p, c);
           tokadd(p, read_escape(p));

test/t/unicode.rb

@@ -33,3 +33,7 @@ assert('braced \u notation test') do
   assert_equal("\xF0\x90\x80\x80", "\u{10000}")
   assert_equal("\xF4\x8F\xBF\xBF", "\u{10FFFF}")
 end
+
+assert('braced multiple \u notation test') do
+  assert_equal("ABC", "\u{41 42 43}")
+end