Thank you for the clarification. I see.
I guess I am handicapped by having converted the parser code to /360
assembler language.
Others might have studied the skeleton code. Maybe a comment to the
effect that one should forget having seen this assignment?
On 28 January 2013 18:02, Akim Demaille <a...@lrde.epita.fr> wrote:
>
> Le 28 janv. 2013 à 17:11, John P. Hartmann <jphartm...@gmail.com> a écrit :
>
>> On 28 January 2013 16:43, John P. Hartmann <jphartm...@gmail.com> wrote:
>>> But here is another one:
>>>
>>> | dotobyfors dotobyfor { listend($1, $2); }
>>>
>>> Gets "warning: unset value: $$".
>>>
>>> I'm relying on the default $$ = $1 here.
>>>
>>> Or is there something more subtle going on? Or (shudder) is the
>>> default applied only when there is no explicit semantic code? (In
>>> which case I have a lot of grammars to fix.)
>>
>> Adding $$ = $1 kept Bison quiet.
>>
>> Here is a variation that gets Unused value $1.
>>
>> assign : variable ASSIGN expression
>> {
>> $$->term.oper = op_assign;
>>
>> This is also fixed by stating the default action.
>>
>> Surely this is a bug (?).
>
> Actually, I prefer to leave this as is, instead of promoting
> the fact that $$ = $1 is run beforehand. This is not true
> for all the configurations (where the warning is right),
> so I still prefer pushing the users towards explicitly
> perform their $$ = $1 themselves.
>
> Besides, you are not supposed to know that $$ = $1 is always
> run before. The documentation should only state that if
> no action at all is provided, then this action defaults to
> { $$ = $1; }.
>
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