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Re: bison info doc - precedence in recursive parsing
From: |
Anand Akhare |
Subject: |
Re: bison info doc - precedence in recursive parsing |
Date: |
Mon, 4 Feb 2019 09:10:20 +0530 |
Pasting link of info doc
https://www.gnu.org/software/bison/manual/html_node/How-Precedence.html#How-Precedence
> On 03-Feb-2019, at 12:20 PM, <address@hidden> <address@hidden> wrote:
>
> Hello,
> in info doc of bison, it is mentioned that rule gets its precendence from
> last terminal symbol.
> pasted below:
> The first effect of the precedence declarations is to assign precedence
> levels to the terminal symbols declared. The second effect is to assign
> precedence levels to certain rules: each rule gets its precedence from the
> last terminal symbol mentioned in the components.
>
> For below example, how the parsing will happen if above is the case:
>
> nonterm1 : nonterm2
> | nonterm1 term1 nonterm3 nonterm4
> | nonterm1 term2 nonterm5 nonterm6
>
> One more example:
> nonterm1 : nonterm2 nonterm3
> | nonterm1 term1 nonterm2 nonterm3
> | nonterm1 term2 nonterm2 nonterm3
>
> Consider first example. First parser will consume nonterm2 then for term1
> rule, nonterm1 will hold nonterm2 value and term2 higher precedence than
> term1, parser have to pass value to nonterm1 in term2 rule but it is invalid
> if we provide term1 precedence to term1 rule because as the statement
> suggests, last terminal token gives rule precedence. Assigning value of
> "nonterm3 nonterm4" to nonterm1 in term2 rule is not possible or is it?
> Value is for term or nonterm but not partial set of symbols in rule. is it
> right?
> Does the info doc says last terminal symbol as last but one symbol which if
> it is terminal?
>
> Regards,
> Anand
- bison info doc - precedence in recursive parsing, anand, 2019/02/03
- Re: bison info doc - precedence in recursive parsing,
Anand Akhare <=
- Re: bison info doc - precedence in recursive parsing, Hans Åberg, 2019/02/04
- Re: bison info doc - precedence in recursive parsing, Akim Demaille, 2019/02/04
- Re: bison info doc - precedence in recursive parsing, Hans Åberg, 2019/02/04
- Re: bison info doc - precedence in recursive parsing, Uxio Prego, 2019/02/04
- Re: bison info doc - precedence in recursive parsing, Hans Åberg, 2019/02/04
- Re: bison info doc - precedence in recursive parsing, Akim Demaille, 2019/02/05
- Re: bison info doc - precedence in recursive parsing, Hans Åberg, 2019/02/05
- Re: bison info doc - precedence in recursive parsing, Akim Demaille, 2019/02/05
- Re: bison info doc - precedence in recursive parsing, Hans Åberg, 2019/02/05
- Re: bison info doc - precedence in recursive parsing, Hans Åberg, 2019/02/10