RE: errata/583: comment_text allows \n and */

From: Michael McNamara (mac@verisity.com)
Date: Tue May 11 2004 - 13:00:00 PDT

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    The following reply was made to PR errata/583; it has been noted by GNATS.

    From: Michael McNamara <mac@verisity.com>
    To: Shalom Bresticker <Shalom.Bresticker@freescale.com>
    Cc: etf-bugs@boyd.com
    Subject: RE: errata/583: comment_text allows \n and */
    Date: Tue, 11 May 2004 13:14:02 -0700

     Good points.
     
     Something else to consider is an enhancement that allows non-ascii
     characters in comments. (Japanese, Chinese, French, German, Hebrew, et
     cetera)
     
     -- On May 11 2004 at 02:50, Shalom Bresticker sent a message:
    > To: etf-bugs@boyd.com
    > Subject: "errata/583: comment_text allows \n and */"
    > >Number: 583
    > >Category: errata
    > >Originator: Shalom Bresticker <Shalom.Bresticker@freescale.com>
    > >Description:
    >
    > Geoffrey.Coram@analog.com wrote me the following:
    >
    > I'm working in the Verilog-AMS committee and I noticed a
    > small glitch in the LRM definition for comments. Both
    > the AMS LRM and 1364-2004-d2 contain the following:
    >
    > one_line_comment ::= // comment_text \n
    > block_comment ::= /* comment_text */
    > comment_text ::= { Any_ASCII_character }
    >
    > However, a newline should be excluded from one_line_comment.
    >
    > It's not clear what the termination is.
    >
    > // this should not
    > match the syntax
    >
    > but "this should not \n match the syntax" is comment_text
    > because I can use it in between /* and */
    >
    > Maybe I'm thinking too much like a "greedy" parser.
    >
    > A greedy parser is one that tries to fit as many tokens
    > into the pattern as possible.
    >
    > Thus, if I had a pattern like "a*a" where * was to match
    > any ascii character, then from the following input stream
    > afooabarafoofoo
    > the parser would match the pattern
    > afooabara
    > and leave "foofoo" on the stack to look for the next pattern.
    >
    > For the case of the comments, we want the \n (or the */) to
    > terminate the pattern.
    >
    > A non-greedy parser would pick out "afooa" from the stream
    > to match the pattern and pass that as a token, and then
    > pick from from "barafoofoo" to find the next pattern.
    >
    > -Geoffrey
    >
    > Similarly, comment_text allows for */ to appear in it.
    >
    > Strictly speaking, there probably should be two different
    > types of comment text.
    >
    > Shalom
    >
    > --
    > Shalom Bresticker Shalom.Bresticker @freescale.com
    > Design & Reuse Methodology Tel: +972 9 9522268
    > Freescale Semiconductor Israel, Ltd. Fax: +972 9 9522890
    > POB 2208, Herzlia 46120, ISRAEL Cell: +972 50 5441478
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