[antlr-interest] about range float and stuff

Bart Kiers bkiers at gmail.com
Fri Nov 4 10:30:15 PDT 2011 

I only know that Terence's solution solves the OP's problem AFAIK, whereas
yours I am not sure of: I simply find it too verbose to fully grasp by only
reading through it. Sorry.

Bart.


On Fri, Nov 4, 2011 at 6:18 PM, Jim Idle <jimi at temporal-wave.com> wrote:

> You may prefer whatever solution you like of course (though these are not
> the same solution), but you should be accurate about the other solutions
> and take the time to read through them.
>
> Jim
>
> > -----Original Message-----
> > From: antlr-interest-bounces at antlr.org [mailto:antlr-interest-
> > bounces at antlr.org] On Behalf Of Bart Kiers
> > Sent: Friday, November 04, 2011 10:13 AM
> > To: antlr-interest at antlr.org interest
> > Subject: Re: [antlr-interest] about range float and stuff
> >
> > If your (Jim) definition of "without code" means no @members section,
> > then I find it a bit of an odd definition since the lexer rules from
> > http://www.antlr.org/wiki/display/ANTLR3/Lexer+grammar+for+floating+poi
> > nt,+dot,+range,+time+specs
> > are
> > littered with `{ ... }` code blocks: not what I'd call "without code".
> > I much prefer the solution proposed by Terence in
> > http://www.antlr.org/wiki/pages/viewpage.action?pageId=3604497 (which I
> > based my suggestion on): far less verbose than the first option, IMO.
> >
> > Bart.
> >
> >
> > On Fri, Nov 4, 2011 at 5:59 PM, Bart Kiers <bkiers at gmail.com> wrote:
> >
> > > The only wiki-link posted in this thread is
> > >
> > http://www.antlr.org/wiki/display/ANTLR3/Lexer+grammar+for+floating+po
> > > int,+dot,+range,+time+specs which contains Java code, so you must
> > mean
> > > something else (of which, I have no idea of)...
> > >
> > > Bart.
> > >
> > >
> > > On Fri, Nov 4, 2011 at 5:47 PM, Jim Idle <jimi at temporal-wave.com>
> > wrote:
> > >
> > >> The example on the Wiki already does all of this in the lexer, but
> > >> without any code.
> > >>
> > >> Jim
> > >>
> > >> > -----Original Message-----
> > >> > From: antlr-interest-bounces at antlr.org [mailto:antlr-interest-
> > >> > bounces at antlr.org] On Behalf Of Bart Kiers
> > >> > Sent: Friday, November 04, 2011 7:12 AM
> > >> > To: Fabien Hermenier
> > >> > Cc: antlr-interest at antlr.org
> > >> > Subject: Re: [antlr-interest] about range float and stuff
> > >> >
> > >> > You're welcome Fabien, but note that it most likely looks a lot
> > >> > like something I found on the ANTLR Wiki: so I can't claim credit
> > >> > for it (perhaps a small part! :)).
> > >> > I'll have a look later on and see if I can dig up the Wiki page.
> > >> >
> > >> > Regards,
> > >> >
> > >> > Bart.
> > >> >
> > >> >
> > >> > On Fri, Nov 4, 2011 at 3:04 PM, Fabien Hermenier
> > >> > <hermenierfabien at gmail.com>wrote:
> > >> >
> > >> > >  Thanks Bart, I think I have understand your approach and
> > indeed,
> > >> > > it seems beautiful and simple.
> > >> > > I will try your solution during the week-end.
> > >> > >
> > >> > > Fabien.
> > >> > >
> > >> > > Le 04/11/11 02:48, Bart Kiers a écrit :
> > >> > >
> > >> > > Hi Fabien,
> > >> > >
> > >> > >  Handling this in the parser will make your life much harder
> > than
> > >> > > it has to. Doing it in the lexer, you will need a bit of custom
> > >> > > code,
> > >> > but
> > >> > > I'd go for something similar to this (something like it is on
> > the
> > >> > WIki
> > >> > > somewhere, but can't find it...):
> > >> > >
> > >> > >  grammar RangeDemo;
> > >> > >
> > >> > >  @lexer::members {
> > >> > >
> > >> > >    java.util.Queue<Token> tokens = new
> > >> > > java.util.LinkedList<Token>();
> > >> > >
> > >> > >    public void offer(int ttype, String ttext) {
> > >> > >     emit(new CommonToken(ttype, ttext));
> > >> > >   }
> > >> > >
> > >> > >   @Override
> > >> > >   public void emit(Token t) {
> > >> > >     state.token = t;
> > >> > >     tokens.offer(t);
> > >> > >   }
> > >> > >
> > >> > >   @Override
> > >> > >   public Token nextToken() {
> > >> > >     super.nextToken();
> > >> > >     return tokens.isEmpty() ? Token.EOF_TOKEN : tokens.poll();
> > >> > >   }
> > >> > > }
> > >> > >
> > >> > >  parse
> > >> > >   :  (t=. {System.out.printf("\%-10s \%s\n",
> > tokenNames[$t.type],
> > >> > > $t.text);})* EOF
> > >> > >   ;
> > >> > >
> > >> > >  FLOAT
> > >> > >   :  INT '..'   {offer(INT, $INT.text); offer(RANGE, "..");}
> > >> > >   |  OCTAL '..' {offer(OCTAL, $OCTAL.text); offer(RANGE, "..");}
> > >> > >   |  '.' DIGITS
> > >> > >   |  DIGITS '.' DIGITS?
> > >> > >   ;
> > >> > >
> > >> > >  RANGE
> > >> > >   :  '..'
> > >> > >   ;
> > >> > >
> > >> > >  INT
> > >> > >   :  '1'..'9' DIGIT*
> > >> > >   |  '0'
> > >> > >   ;
> > >> > >
> > >> > >  OCTAL
> > >> > >   :  '0' ('0'..'7')+
> > >> > >    ;
> > >> > >
> > >> > >  fragment DIGITS : DIGIT+;
> > >> > > fragment DIGIT  : '0'..'9';
> > >> > >
> > >> > >  SPACE
> > >> > >   :  (' ' | '\t' | '\r' | '\n') {skip();}
> > >> > >   ;
> > >> > >
> > >> > >  And if you run the class:
> > >> > >
> > >> > >  import org.antlr.runtime.*;
> > >> > >
> > >> > >  public class Main {
> > >> > >   public static void main(String[] args) throws Exception {
> > >> > >     String src = "..07..8.5 1.9..02 1..3.4";
> > >> > >     RangeDemoLexer lexer = new RangeDemoLexer(new
> > >> > ANTLRStringStream(src));
> > >> > >     RangeDemoParser parser = new RangeDemoParser(new
> > >> > > CommonTokenStream(lexer));
> > >> > >     System.out.println("Parsing: '" + src + "'");
> > >> > >     parser.parse();
> > >> > >   }
> > >> > > }
> > >> > >
> > >> > >  You'll see the following being printed to the console:
> > >> > >
> > >> > >  Parsing: '..07..8.5 1.9..02 1..3.4'
> > >> > > RANGE      ..
> > >> > > OCTAL      07
> > >> > > RANGE      ..
> > >> > > FLOAT      8.5
> > >> > > FLOAT      1.9
> > >> > > RANGE      ..
> > >> > >  OCTAL      02
> > >> > > INT        1
> > >> > > RANGE      ..
> > >> > > FLOAT      3.4
> > >> > >
> > >> > >
> > >> > >  Regards,
> > >> > >
> > >> > >  Bart.
> > >> > >
> > >> > >
> > >> > >
> > >> > >  On Fri, Nov 4, 2011 at 7:28 AM, Fabien Hermenier <
> > >> > > hermenierfabien at gmail.com> wrote:
> > >> > >
> > >> > >> Hi
> > >> > >>
> > >> > >> In an earlier version of my language, I had to parse range of
> > >> > >> integers in various base. Now I want to include float. I have
> > >> > >> read
> > >> > >>
> > >> > >>
> > >> >
> > http://www.antlr.org/wiki/display/ANTLR3/Lexer+grammar+for+floating
> > >> > +p
> > >> > >> oint,+dot,+range,+time+specs
> > >> > >> but I've still got some questions.
> > >> > >>
> > >> > >> All the work seems to be done at the lexer level so the type of
> > >> > >> the following tokens will be as example:
> > >> > >> 5 : DECIMAL_LITTERAL
> > >> > >> 07 : OCTAL_LITTERAL
> > >> > >> 7.5: FLOATING_POINT_LITTERAL
> > >> > >> 5..7 : DOTDOT
> > >> > >>
> > >> > >> In the last example, the result is not very convenient because
> > I
> > >> > will
> > >> > >> still have to extract the bounds and compute their type by
> > >> > >> myself which seems quite redundant with the job performed by
> > the lexer.
> > >> > >> May be I am missing something ?
> > >> > >>
> > >> > >> I would rather be able to express the range at the parser level
> > >> > which
> > >> > >> seems much more convenient to me:
> > >> > >> range: FLOATING_POINT_LITTERAL DOTDOT FLOATING_POINT_LITTERAL.
> > >> > >> In this way, I will also be able to manage the possible spaces
> > >> > >> between the bounds and the DOTDOT.
> > >> > >>
> > >> > >> So, am I right to try to parse range at the parser level ? Or
> > is
> > >> > >> there a solution to extract easily the bounds with their type
> > if
> > >> > >> I
> > >> > am
> > >> > >> doing the job at the lexer level ?
> > >> > >>
> > >> > >> Thanks in advance,
> > >> > >> Fabien.
> > >> > >>
> > >> > >>
> > >> > >>
> > >> > >>
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