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## Re: Locations and mid-rule actions

**From**: |
Frank Heckenbach |

**Subject**: |
Re: Locations and mid-rule actions |

**Date**: |
Wed, 22 Dec 2004 13:10:55 +0100 |

**User-agent**: |
semail 20041018 |

Paul Eggert wrote:
>* > BTW, the documentation (changes of 12 Dec, sorry if it's been*
>* > updated meanwhile) seems a bit unclear on whether or not it is only*
>* > defined if N = 0:*
>* >*
>* > : where @code{YYRHSLOC (rhs, k)} is the location of the @var{k}th symbol*
>* > : in @var{rhs} when @var{k} is positive, and the location of the symbol*
>* > : just before the reduction when @var{k} is zero.*
>* >*
>* > This doesn't say that N = 0 is required.*
>* >*
>* > : For consistency with semantic actions, valid indexes within the*
>* > : right hand side range from 1 to @var{n}. When @var{n} is zero, only 0 is *
>* > a*
>* > : valid index, and it refers to the symbol just before the reduction.*
>* >*
>* > But this would imply so. So which one is true?*
>* *
>* They're both true. The first one doesn't state the implication (it*
>* states something else), and the second one does.*
So YYRHSLOC(yyRhs, 0) is *not* valid for if N > 0, right? (Because
the 2nd paragraph says the range is from 1 to N.)
Then I'd suggest to put this restriction in the first paragraph as
well because by reading just this paragraph one would assume it's
always available.
< just before the reduction when @var{k} is zero.
>* just before the reduction when @var{k} is zero and @var{n} is zero.*
Frank
--
Frank Heckenbach, address@hidden
http://fjf.gnu.de/
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