Fwd: Re: Two small lexical syntax issues in the 1364-2001 LRM

From: Stefen Boyd (stefen@boyd.com)
Date: Tue Mar 23 2004 - 05:42:32 PST

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    >Message-ID: <405F26EE.7030105@bluespec.com>
    >Date: Mon, 22 Mar 2004 12:48:30 -0500
    >From: "Rishiyur S. Nikhil" <nikhil@bluespec.com>
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    >To: Shalom.Bresticker@motorola.com
    >Cc: etf@boyd.com
    >Subject: Re: Two small lexical syntax issues in the 1364-2001 LRM
    >References: <Pine.GSO.4.10.10403202017010.13933-100000@eagle>
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    >
    >Hi Shalom,
    >
    >I'm confused by your statement. The para after Syntax 19-2 on
    >page 352 says:
    >
    > > The macro text can be any arbitrary text specified on the same
    > > line as the text macro name. If more than one line is necessary
    > > to specify the text, the newline shall be preceded by a backslash
    > > (\). The first newline not preceded by a backslash shall end the
    > > macro text. The newline preceded by a backslash shall be replaced
    > > in the expanded macro with a newline (but without the preceding
    > > backslash character).
    >
    >which seems to allow multi-line `defines.
    >
    >Where can I read about issue #485?
    >
    >Thanks,
    >
    >Nikhil
    >
    >Shalom.Bresticker@motorola.com wrote:
    >
    > > Thanks.
    > >
    > > Please note that the LRM does not really allow multi-line `defines.
    > > See a fuller discussion in our issue #485.
    > >
    > > Shalom
    > >
    > >
    > > On Fri, 19 Mar 2004, Rishiyur S. Nikhil wrote:
    > >
    > >
    > >>Hello Shalom,
    > >>
    > >>(Please forward this to whomever it may concern on the 1364-2001
    > >> committee.)
    > >>
    > >>My colleague Mieszko Lis and I have noticed two small lexical syntax
    > >>issues in the 1364-2001 LRM (I believe the version we have is:
    > >>P1364-2005/D3).
    > >>
    > >>Regards,
    > >>
    > >>Nikhil
    > >>----------------------------------------------------------------
    > >>Rishiyur S. Nikhil, Ph.D.,CTO Email: nikhil@bluespec.com
    > >>Bluespec, Inc. http://www.bluespec.com
    > >>200 West St., 4th flr. Tel: +1.781.250.2203
    > >>Waltham, MA 02451, USA Cell: +1.617.359.0747
    > >>
    > >>
    > >>================================================================
    > >>Issue 1:
    > >>
    > >>There seems to be a small inconsistency between the text and the BNF
    > >>concerning the definition of whitespace.
    > >>
    > >>The text in Section 2.2 says:
    > >>
    > >> White space shall contain the characters for spaces, tabs,
    > >> newlines, and formfeeds.
    > >>
    > >>The BNF in A.9.5 says:
    > >>
    > >> white_space ::= space | tab | newline | eof
    > >>
    > >>i.e., the former talks about formfeeds but not eofs, whereas the
    > >>latter talks about eofs but not formfeeds.
    > >>
    > >>================================================================
    > >>Issue 2:
    > >>
    > >>The BNF for escaped identifiers (in A.9.3) says:
    > >>
    > >> escaped_identifier ::= \ { Any_ASCII_character_except_white_space
    > } white_space
    > >>
    > >>I believe this will allow the empty identifier (an identifier with
    > >>zero characters, '\' followed by whitespace). Is this intended, or
    > >>should there be at least one character in the identifier?
    > >>
    > >>If the empty identifier is intended, then there may be an ambiguity
    > >>with the multiline `defines. In a multiline `define, each line except
    > >>the last should end with a '\' followed by a newline, which would be
    > >>legal syntax for an empty escaped identifier. So, should it be lexed
    > >>as an empty identifier within the `define definition, or as a
    > >>continuation signal for the next line?
    > >>
    > >>================================================================
    > >>
    > >>
    > >
    > >

    --------------------
    Stefen Boyd Boyd Technology, Inc.
    stefen@BoydTechInc.com (360)666-6957
    www.BoydTechInc.com

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