Re: [Grammatica-users] Grammar for "Nesting"

[Patrick M Gremo]

Thanks for all of your assistance.  You have been very helpfull.


I think I'm supper close.  Here is the grammar I have now.

===================

%header%

GRAMMARTYPE = "LL"


%tokens%

USER_UNARY            = <<[a-zA-Z][a-zA-Z0-9_]*>>
STRING                    = <<("[^"]*")>>
WHITESPACE            = <<[ \t\n\r]+>> %ignore%


%productions%

_expression_     = Message ;

Message = Factor Term? ;

Term = MethodCall Term? ;
                               
Factor    = MethodCall
                | STRING ;
               
MethodCall = USER_UNARY ;

================================

When I try with this data:

    object call1 call2

I get this (from TreePrinter):

_expression_(2001)
  Message(2002)
    Factor(2004)
      MethodCall(2005)
        USER_UNARY(1003): "object", line: 1, col: 1
    Term(2003)
      MethodCall(2005)
        USER_UNARY(1003): "call1", line: 1, col: 8
      Term(2003)
        MethodCall(2005)
          USER_UNARY(1003): "call2", line: 1, col: 14


This is very close, except I want the tree "flipped"  so that "object" is at the bottom.

I did some tests and this grammar lets only the Factor be a String or MethodCall. This is good as I don't want Strings to be missinterpretted as a method call.




Thanks

address@hidden wrote: -----

> To: address@hidden
> From: Per Cederberg <address@hidden>
> Sent by: address@hidden
> Date: 07/25/2005 03:48PM
> Subject: Re: [Grammatica-users] Grammar for "Nesting"
>
> Well, Grammatica uses LL grammars so they are recursive on
> the right-hand side. Your production is identical to this
> one:
>
> Message = MethodCall
>         | Object MethodCall
>         | Message MethodCall ;
>
> This describes a sequence of MethodCall productions with a
> possible end of an Object and then a MethodCall. To write
> this in a right-recursive way, you'd simply write this
> instead:
>
> Message = MethodCall
>         | Object MethodCall
>         | MethodCall Message ;
>
> Which in turn can be simplified to:
>
> Message = MethodCall [Message]
>         | Object MethodCall ;
>
> /Per
>
> On mon, 2005-07-25 at 12:45 -0500, Patrick M Gremo wrote:
> > This is close.
> > 
> > 
> > 
> > But I think what I need is something like:
> > 
> > Message = [Object | Message] MethodCall
> > 
> > But this gives me an infinite loop.
> > 
> > I think I can describe it as:
> > 
> > A Message can have an Object OR another Message coupled with a MethodCall.
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > I think a production for Message could look like this:
> > 
> >   Message = MethodCall Message?
> >           | Object Message? ;
> > 
> > This will allow an infinite list of method calls and
> > objects mixed together. If the Object production can
> > only be placed at the end, you'd write the production
> > like this:
> > 
> >   Message = MessageCall Message?
> >           | Object ;
> > 
> > Cheers,
> > 
> > /Per
> > 
> > On sun, 2005-07-24 at 19:40 -0500, Patrick M Gremo wrote:
> > > 
> > > I'm trying to create a kind of "reverse" call stack type of thing.  It
> > > sounds easy but for some reason I just can't figure it out.
> > > 
> > > I have this:
> > > 
> > > (object | methodCall) methodCall methodCall methodCall ...
> > > 
> > > 
> > > I want a tree like:
> > > 
> > > message
> > >    |-methodCall
> > >    |-message
> > >         |-methodCall
> > >         |-message
> > >              |-methodCall
> > >              |-message
> > >                   |-object | methodCall
> > > 
> > > 
> > > 
> > > 
> > > _______________________________________________
> > > Grammatica-users mailing list
> > > address@hidden
> > > http://lists.nongnu.org/mailman/listinfo/grammatica-users
> > > 
> > _______________________________________________
> > Grammatica-users mailing list
> > address@hidden
> > http://lists.nongnu.org/mailman/listinfo/grammatica-users
>
>
>
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