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Re: Precedence declarations applied to rules

From: Frank Heckenbach
Subject: Re: Precedence declarations applied to rules
Date: Sun, 18 May 2003 20:41:50 +0200

Hans Aberg wrote:

> But if one should implement a precedence system for rules into Bison,
> instead of the old one using tokens, then it might look like this:
>   %precedence {
>   ...
>   %left E: E_1 ... E_k
>   ...
>   }
> This should mean that the precedence rules only apply to what is quoted
> within each %precedence group.

A minor problem IMHO is that it's a little redundant having to
repeat the complete rules for the precedence declaration. I'd prefer
a way to, say, name certain rules and refer to their names. But
that's only a syntactic detail, of course.

Another syntactic observation: If %precedence forms a "{}" section
as in your example, it would lend itself neatly to allowing for
several independent groups of precendences, as in my first
suggestion. (Which does not mean that I plan to implement it now;
for me, the no-default-precedence should be enough.)


Frank Heckenbach, address@hidden
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