W3C home > Mailing lists > Public > public-cwm-talk@w3.org > January to March 2009

Re: n3 grammar : ambiguity for integer and decimal

From: <jos.deroo@agfa.com>
Date: Sat, 21 Feb 2009 18:33:51 +0100
To: lc.pvrr@orange.fr
Cc: "DIG group" <diggers@csail.mit.edu>, "++jean marc vanel" <jeanmarc.vanel@gmail.com>, "cwm talk" <public-cwm-talk@w3.org>, public-cwm-talk-request@w3.org, "Yosi Scharf" <syosi@mit.edu>, "Tim Berners-Lee" <timbl@w3.org>
Message-ID: <OFA87FCB2A.2E840EFB-ONC1257564.005F9E08-C1257564.00607BCE@agfa.com>
Luc,

> There is no problems with "@is", "@of", and "@a"

and I think that is why Tim and Dan in
http://www.w3.org/TeamSubmission/n3/#keywords
say that

[[
The grammar is written as without reference to the keywords system at all,
on the assumption that the string has been preprocessed by a keyword 
processor
to put a "@" on all keywords and a ":" on all qnames in the default 
namespace. 
]]


Kind regards,

Jos De Roo | Agfa HealthCare
Senior Researcher | HE/Advanced Clinical Applications Research
T  +32 3444 7618
 http://www.agfa.com/w3c/jdroo/

Quadrat NV, Kortrijksesteenweg 157, 9830 Sint-Martens-Latem, Belgium
http://www.agfa.com/healthcare



"luc peuvrier at home" <lc.pvrr@orange.fr> 
Sent by: public-cwm-talk-request@w3.org
02/21/2009 05:56 PM

To
"Tim Berners-Lee" <timbl@w3.org>
cc
Jos De Roo/AMDUS/AGFA@AGFA, "cwm talk" <public-cwm-talk@w3.org>, "DIG 
group" <diggers@csail.mit.edu>, "Yosi Scharf" <syosi@mit.edu>, "++jean 
marc vanel" <jeanmarc.vanel@gmail.com>
Subject
Re: n3 grammar : ambiguity for integer and decimal







Tim,
 
Thank you to take care of my spot.
 
An other ambiguity I discovered writing n3 parser that I did not 
mentionned is about "is" "of" and "a" keyword.
There is no problems with "@is", "@of", and "@a" since the @ make able to 
distinguish to a qname, it is not the case with "is" "of" and "a" keyword 
because it also match qname non terminal.
 
I have this since I have the following rules not in n3 grammar:
verb <- ( "is" | "@is" ) expression ( "of" | "@of" )
 
for the entry  " :jmv is :guru of :luc ."
 
it match at the same time
 
simpleStatement 
  |
  subject propertylist
  |       |
  |       verb object objecttail propertylisttail
  |       |    |      |          |
  |       |    |      void       void
:jmv      is   :guru
 
and
 
simpleStatement 
  |
  subject propertylist 
  |       |
  |       verb                  object objecttail propertylisttail
  |       |                     |      |          |
  |       "is" expression "of"  |      |          |
  |       |    |          |     |      |          |
:jmv      is   :guru      of    :luc   void       void
 
so there is a shift/reduce conflict between
verb <- expression
and
verb <- is expression of
 
this can be solve saying qname can not have the value "is" "of"
 
Best regards
Luc Peuvrier
 
----- Original Message ----- 
From: Tim Berners-Lee 
To: luc peuvrier at home 
Cc: cwm talk ; DIG group ; Yosi Scharf 
Sent: Saturday, February 21, 2009 12:40 AM
Subject: Re: n3 grammar : ambiguity for integer and decimal

Luc, thanks for spotting that. 

It seems to make sense.  I have checked it in as the new n3.n3


Tim

On 2009-02 -12, at 18:26, luc peuvrier at home wrote:

Hi,
 
Looking for integer and decimal non terminal ( token ) definition on 
following n3 grammar specification:
http://www..w3.org/2000/10/swap/grammar/n3-report.html
 
and
 
http://www.w3.org/2000/10/swap/grammar/n3.n3
 
The ebnf definition for integer and decimal are:
 
integer : [-+]?[0-9]+
 
decimal : [-+]?[0-9]+(\.[0-9])?
 
There is an ambiguity since "123" ( for example ) match integer and 
decimal
 
I propose
decimal : [-+]?[0-9]+\.[0-9]*
 
Width the above definition "123" match only integer, "123." match decimal. 
This look like C and Java standard for numéric constants
 
Best regards
Luc Peuvrier
Received on Saturday, 21 February 2009 17:34:36 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Saturday, 21 February 2009 17:34:39 GMT