[antlr-interest] forcing parenthesis (no precedence)

hakan eryargi hakan.eryargi at gmail.com
Wed Jul 15 23:57:54 PDT 2009


thank you but i can't get it. simply making AND's and OR's have same
precedence doesnt force user to use parenthesizes. expression is
simply evaluated from left to right ?

regards,
hakan

Just steal the expression tree from something like Java.g, remove the
things you don't need and make AND and OR tokens the same precedence in
the same way that '+' and '=-' are.

In general stealing rules from the example grammars (see the download
section) will get you a long way!

On Wed, Jul 15, 2009 at 12:20 PM, hakan eryargi<hakan.eryargi at gmail.com> wrote:
> hello,
>
> i want to create a grammar for simple expressions and AND, OR
> statements. AND's and OR's have no precedence, so i want the user to
> explicitly use parenthesis if AND's and OR's mixed. how can i define
> such a grammar ?
>
> for example these are valid:
> EXP
> EXP & EXP
> EXP | EXP | EXP
> EXP & (EXP | EXP)
> (EXP | EXP) & (EXP | EXP)
>
> these are not:
> EXP & EXP | EXP
> EXP | EXP & EXP | EXP
>
> please note i'm a newbea so handle with care :)
>
> thanks,
> hakan
>


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