Re: AW: How to write SableCC Productions

[Roger Keays <s354157@student.uq.edu.au>]

Hi Bittkau,

> thank you for your help!
>
> I've tried:
>
> Helpers
>   cr = 13 ;
>   lf = 10 ;
> Tokens
>   colon = ':' ;
>   underscore = '_';
>   letter = ['a'..'z'] + ['A'..'Z'];
>   endofline = cr | lf | cr lf ;
>
> Productions
>   il_instruction = labeltag? il_instruction_rest? eol;
>   labeltag = label colon;
>   label = identifier;
>   il_instruction_rest =
>     {il_simple_operation} il_simple_operation |
>     {il_expression} il_expression;
>
>   identifier = letter+;   //not true, test only
>   eol = endofline+;
>
> so far so good, but now I get the error:
> Verifying identifiers.
> PIlSimpleOperation and TIlSimpleOperation undefined.

Your need either a production rule, or a token called il_simple_operation.
You will also need one for il_expression. Also, you will probably find it
simpler to make identifier  a token rather than a production.
You may want to ignore blank space too. Generally you can cut and paste
these rules from existing grammars. I think you want something like:

Helpers
    cr = 13 ;
    lf = 10 ;
    tab = 9 ;
    nondigit = ['_' + [['a' .. 'z'] + ['A' .. 'Z']]];
    digit = ['0' .. '9'];

Tokens
    colon = ':' ;
    eol = cr | lf | cr lf ;
    blank = ( tab | ' ' )+;

    il_simple_operation = 'operation' ; // no idea why
    il_expression = 'expression' ; // just made it up

    // important to have this last, so 'operation' and 'expression'
    // are not analysed as identifiers
    identifier = nondigit (digit | nondigit)*;

Ignored Tokens
    blank;

Productions
    il_instruction = labeltag? il_instruction_rest? eol;
    labeltag = label colon;
    label = identifier;
    il_instruction_rest =
      {il_simple_operation} il_simple_operation |
      {il_expression} il_expression;

Have you downloaded Etienne's thesis (it is at www.sablecc.org)? It
explains everything very well.

Regards,

Roger

 > >
That may be, but I don't know where and how to
define. > > In the meantime I tried to convert the identifier from BNF:
> identifier ::= (letter | ('_' (letter | digit))) {['_'] (letter | digit)}
>
> would be very nice, if somebody could help me.
>
> Mit freundlichen Grüssen
> Rainer Bittkau
>
> Baumer Electric AG, Abt. Betriebsmittel
> Hummelstrasse 17
> Postfach
> CH-8501 Frauenfeld
> Tel. ++41 52 728 14 55; Fax. ++41 52 728 17 27
> mailto:rbittkau@baumerelectric.com
> http://www.baumerelectric.com
>
>
> -----Ursprüngliche Nachricht-----
> Von: Dan Sandberg [mailto:dan@siliconpoetry.com]
> Gesendet: Dienstag, 5. Juni 2001 19:18
> An: Roger Keays
> Cc: Bittkau Rainer; 'sablecc-list@sable.mcgill.ca'
> Betreff: Re: How to write SableCC Productions
>
>
> Oops.  Thanks for the correction.
>
> -Dan
>
> Roger Keays wrote:
> >
> > On Tue, 5 Jun 2001, Dan Sandberg wrote:
> >
> > > Hi.
> > >
> > > You can't put alternatives in parenthesis.  So:
> > > il_instruction = ( label colon ) ? ( il_simple_operation | il_expression
> > > ) ? eol ;
> > >
> > > should be
> > >
> > > il_instruction = ( label colon )? il_instruction_rest? eol;
> > > il_instruction_rest = {simple_operator} il_simple_operator |
> > >                       {expression} il_expression;
> > >
> >
> > Is this right? I though parantheses indicated ignored alternatives. I
> > think what Bittkau is looking for is:
> >
> > il_instruction =  labelcolon? il_instruction_rest? eol;
> > labelcolol = label colon
> > il_instruction_rest = {simple_operator} il_simple_operator |
> >                        {expression} il_expression;
> >
> > Regards,
> >
> > Roger
> >
> > > [Alternatives need to be named, using the {name} notation]
> > >
> > > Also, I don't see where the label token was defined in the example you
> > > gave.
> > >
> > > I don't know of any tools that convert from BNF automatically.
> > >
> > > -Dan
> > >
> > > Bittkau Rainer wrote:
> > > >
> > > > I'm at the very first steps to write a compiler for the IEC 61131-3
> PLC
> > > > language.
> > > > The following BNF fragment
> > > >
> > > > il_instruction ::= [label':'][il_simple_operation | il_expression] EOL
> {EOL}
> > > >
> > > > transformed to SableCC
> > > >
> > > > Tokens
> > > >   colon = ':' ;
> > > >   endofline = cr | lf | cr lf;
> > > >   eol = endofline+;
> > > > Productions
> > > >   il_instruction = ( label colon ) ? ( il_simple_operation |
> il_expression )
> > > > ? eol ;
> > > >
> > > > Error message:
> > > > org.sablecc.sablecc.parser.ParserException: [6,36] TSemicolon TBar
> excepted.
> > > >
> > > > [6,36] is the position of the first '?'
> > > > What is wrong with it?
> > > >
> > > > Are there any tools to do the transformation? (there are about 250
> other
> > > > productions to do)
> > > >
> > > > TIA
> > > >
> > > > Mit freundlichen Grüssen
> > > > Rainer Bittkau
> > > >
> > > > Baumer Electric AG, Abt. Betriebsmittel
> > > > Hummelstrasse 17
> > > > Postfach
> > > > CH-8501 Frauenfeld
> > > > Tel. ++41 52 728 14 55; Fax. ++41 52 728 17 27
> > > > mailto:rbittkau@baumerelectric.com
> > > > http://www.baumerelectric.com
> > >
>