> On Sep 9, 2022, at 5:53 PM, John Naylor <john.naylor@enterprisedb.com> wrote:
>
> On Thu, Sep 8, 2022 at 7:32 PM Daniel Gustafsson <daniel@yesql.se> wrote:
>> [v3]
>
> Note that the grammar has shift-reduce conflicts. If you run a fairly
> recent Bison, you can show them like this:
>
> bison -Wno-deprecated -Wcounterexamples -d -o filterparse.c filterparse.y
>
> filterparse.y: warning: 2 shift/reduce conflicts [-Wconflicts-sr]
> filterparse.y: warning: shift/reduce conflict on token C_INCLUDE
> [-Wcounterexamples]
> Example: • C_INCLUDE include_object pattern
> Shift derivation
> Filters
> ↳ 3: Filter
> ↳ 4: • C_INCLUDE include_object pattern
> Reduce derivation
> Filters
> ↳ 2: Filters Filter
> ↳ 1: ε • ↳ 4: C_INCLUDE include_object pattern
> filterparse.y: warning: shift/reduce conflict on token C_EXCLUDE
> [-Wcounterexamples]
> Example: • C_EXCLUDE exclude_object pattern
> Shift derivation
> Filters
> ↳ 3: Filter
> ↳ 5: • C_EXCLUDE exclude_object pattern
> Reduce derivation
> Filters
> ↳ 2: Filters Filter
> ↳ 1: ε • ↳ 5: C_EXCLUDE exclude_object pattern
>
Looks like the last rule for Filters should not be there. I do wonder whether we should be using bison/flex here, seems
likeusing a sledgehammer to crack a nut.
Cheers
Andrew
