From: Harry van Stedum <hvstedum@...4all.nl>
Date: 2007-03-04T22:30:08+09:00
Subject: rex: multiline comment

Hi all,
does anybody using Rex know how to deal with multline comments (of the
kind "/* ... */")?
In the Rex-docs I can find this:

macro
   REMIN         \/\*
   REMOUT      \*\/

rule
            {REMIN}                    { state = :REM ; [:REM_IN,
text] }
  :REM  {REMOUT}                { state = nil ; [:REM_OUT, text] }
  :REM  (.+)(?={REMOUT})     { [:COMMENT, text] }


I changed the rules like this, as I don't want to propagate comments
to the parser:

rule
            {REMIN}                    { state = :REM ; nil }
  :REM  {REMOUT}                { state = nil ; nil }
  :REM  (.+)(?={REMOUT})

I have no idea, nor can I find anywhere, the meaning of "?=" in the
last line, however it seems to work for 1-line comments; it breaks on
multiline comments though. It expands to "(text = ss.scan(/(.+)(?=\*
\/)/))" in the generated ruby-code, where ss is a StringScanner
object.

The "/*" is found/matched, after that the lexer fails with
(JavaLexer::ScanError); it seems the (.+) cannot be matched.

Thanks, Harry