Fix regexp parsing word bug

extra/regexp/regexp-tests.factor

@@ -226,3 +226,10 @@ IN: regexp-tests
 [ t ] [ "s@f" "[a-z.-]@[a-z]" f <regexp> matches? ] unit-test
 [ f ] [ "a" "[a-z.-]@[a-z]" f <regexp> matches? ] unit-test
 [ t ] [ ".o" "\\.[a-z]" f <regexp> matches? ] unit-test
+
+! Bug in parsing word
+[ t ] [
+    "a"
+    R' a'
+    matches?
+] unit-test

extra/regexp/regexp.factor

@@ -290,10 +290,11 @@ TUPLE: regexp source parser ignore-case? ;
     } case ;
 
 : parse-regexp ( accum end -- accum )
-    lexer get dup skip-blank [
-        [ index* dup 1+ swap ] 2keep swapd subseq swap
-    ] change-lexer-column
-    lexer get (parse-token) parse-options <regexp> parsed ;
+    lexer get dup skip-blank
+    [ [ index* dup 1+ swap ] 2keep swapd subseq swap ] change-lexer-column
+    lexer get dup still-parsing-line?
+    [ (parse-token) parse-options ] [ drop f ] if
+    <regexp> parsed ;
 
 : R! CHAR: ! parse-regexp ; parsing
 : R" CHAR: " parse-regexp ; parsing