Re: [lojban] Re: Computer grammar question: non-left recursive RPN?

[Robin Lee Powell <rlpowell@digitalkingdom.org>]

On Wed, Nov 10, 2004 at 09:59:45AM +0100, Jo l'apache wrote:
> there was no operand in the version I submitted you, so it was wrong anyway.
> 
> here is another version :
> 
> rp-expression = rp-operand rp-operand operator
> rp-operand    = operand rp-operand'
> rp-operand'   = rp-operand operator rp-operand' | ()

The second two statements are exactly equivalent to my current
version:

rp-expression <- operand rp-expression-tail

rp-expression-tail <- rp-expression operator rp-expression-tail / ()

I don't think the first line makes any difference.

This works, but it's right recursive, so the parse tree looks wrong.

Thanks for trying, though.

The parser generator I'm using actually has a way around this, but
using it makes the resulting code GPLd.  Not sure what I'm gonna do
about that.

-Robin

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