IBIS - EIA IBIS Open Forum Activity: RE: [IBIS] BIRD135: Add Boo

From: Muranyi, Arpad <Arpad_Muranyi@mentor.com>
Date: Fri Jul 15 2011 - 10:53:39 PDT

Mike,

Thanks for all the research on this topic. While your
argument is convincing that our BNF is incomplete, my
response is the same as before. BIRD 135 was written
to add the missing Boolean, and not to correct the
other problems, defining things, and the completeness
of the BNF, etc... (This is clearly captured by the
title of the BIRD). I still feel that we should leave
this BIRD as is, and deal with the other problems
separately.

Or, we can write a new BIRD with a new title which
would clean up the BNF and provide a full description
and definition for everything under the sun, including
Boolean, with the stipulation that BIRD 135 will be
voted down. But I would rather have someone else write
this BIRD, since I am not that great in the area of BNF.
Would you be interested?

Thanks,

Arpad
========================================================

-----Original Message-----
From: Mike LaBonte [mailto:milabont@cisco.com]
Sent: Friday, July 15, 2011 12:42 PM
To: Muranyi, Arpad; IBIS
Subject: Re: [IBIS] BIRD135: Add Boolean to BNF for IBIS-AMI

In the Open Forum meeting today I agreed with Arpad that this BIRD is
limited to BNF changes, and improvements to the definition of acceptable
Boolean values is a separate matter. However, looking at the full BNF for
AMI I am beginning to think it needs even more work.

The IBIS 5.0 spec has:

In BNF, everything inside <angle brackets> is called a non-terminal. It is
called that because the definition of it is not yet complete. A terminal
definition specifies actual characters, which are not in angle brackets. An
exception is terms like "white-space", "lbracket", and other characters that
have to be built into the BNF language as symbolic names because BNF itself
is expressed using them.

Our BNF does not define the non-terminals <string literals>, <decimal
number>, and <exponent>. In the meeting I heard Bob make the point that if
we add <Boolean> to the BNF then we will have one more undefined
non-terminal (he might not have called it that).

Below my signature I have pasted the BNF that describes <literal> for C++.
Note that they don't use angle brackets, which is a bit confusing. They use
the style where anything not defined is a terminal that has to be taken
exactly as it appears. You can see that <boolean> is the last definition and
it either maps to exactly the words "true" or "false", or they made the same
mistake and left true and false undefined.

Anyway, the BNF in the IBIS spec is insufficient in that you could not pass
it to YACC or BISON to create a parser that is able to discriminate between
string literals, decimal numbers, or exponents. A complete BNF is usually
pretty long.

At this point I have to agree with Bob that we might not want to add Boolean
until we have a better handle on how complete our BNF should be. At a
minimum I would advise adding a definition for Boolean if <Boolean> is added
to <value>:

<Boolean>:
True
False

Mike

http://www.csci.csusb.edu/dick/c++std/cd2/gram.html

          literal:
                  integer-literal
                  character-literal
                  floating-literal
                  string-literal
                  boolean-literal
          integer-literal:
                  decimal-literal integer-suffixopt
                  octal-literal integer-suffixopt
                  hexadecimal-literal integer-suffixopt
          decimal-literal:
                  nonzero-digit
                  decimal-literal digit
          octal-literal:
                  0
                  octal-literal octal-digit
          hexadecimal-literal:
                  0x hexadecimal-digit
                  0X hexadecimal-digit
                  hexadecimal-literal hexadecimal-digit
          nonzero-digit: one of
                  1 2 3 4 5 6 7 8 9
          octal-digit: one of
                  0 1 2 3 4 5 6 7
          hexadecimal-digit: one of
                  0 1 2 3 4 5 6 7 8 9
                  a b c d e f
                  A B C D E F
          integer-suffix:
                  unsigned-suffix long-suffixopt
                  long-suffix unsigned-suffixopt
          unsigned-suffix: one of
                  u U
          long-suffix: one of
                  l L
          character-literal:
                  'c-char-sequence'
                  L'c-char-sequence'
          c-char-sequence:
                  c-char
                  c-char-sequence c-char

          c-char:
                  any member of the source character set except
                          the single-quote ', backslash \, or new-line
character
                  escape-sequence
                  universal-character-name
          escape-sequence:
                  simple-escape-sequence
                  octal-escape-sequence
                  hexadecimal-escape-sequence
          simple-escape-sequence: one of
                  \' \" \? \\
                  \a \b \f \n \r \t \v
          octal-escape-sequence:
                  \ octal-digit
                  \ octal-digit octal-digit
                  \ octal-digit octal-digit octal-digit
          hexadecimal-escape-sequence:
                  \x hexadecimal-digit
                  hexadecimal-escape-sequence hexadecimal-digit
          floating-literal:
                  fractional-constant exponent-partopt floating-suffixopt
                  digit-sequence exponent-part floating-suffixopt
          fractional-constant:
                  digit-sequenceopt . digit-sequence
                  digit-sequence .
          exponent-part:
                  e signopt digit-sequence
                  E signopt digit-sequence
          sign: one of
                  + -
          digit-sequence:
                  digit
                  digit-sequence digit
          floating-suffix: one of
                  f l F L
          string-literal:
                  "s-char-sequenceopt"
                  L"s-char-sequenceopt"
          s-char-sequence:
                  s-char
                  s-char-sequence s-char
          s-char:
                  any member of the source character set except
                          the double-quote ", backslash \, or new-line
character
                  escape-sequence
                  universal-character-name
          boolean-literal:
                  false
                  true

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Received on Fri Jul 15 10:54:12 2011

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RE: [IBIS] BIRD135: Add Boolean to BNF for IBIS-AMI