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Re: Interpretation of EBNF

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  Re: Interpretation of EBNF Keith Thompson <kst-u@mib.org> - 2019-02-24 12:34 -0800
    Re: Interpretation of EBNF David Brown <david.brown@hesbynett.no> - 2019-02-25 09:57 +0100

#141244 — Re: Interpretation of EBNF

ram@zedat.fu-berlin.de (Stefan Ram) writes:
>   The EBNF of C reads (excerpt):
>
> unary-expression:
> postfix-expression
> unary-operator unary-expression
>
>   . The following question surely serves no practical demand,
>   but just for the sake of correctly interpreting EBNF:
>
>   The above surely allows a unary expression to be preceded
>   by a finite number of minus signs (unary operators).
>
>   When there is an infinite number (say Aleph_0) of minus signs
>   and then a unary-expression, is this also a unary expression?

I'll let you know as soon as I finish parsing this infinite input.

-- 
Keith Thompson (The_Other_Keith) kst-u@mib.org  <http://www.ghoti.net/~kst>
Will write code for food.
void Void(void) { Void(); } /* The recursive call of the void */

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#141288

On 24/02/2019 21:34, Keith Thompson wrote:
> ram@zedat.fu-berlin.de (Stefan Ram) writes:
>>   The EBNF of C reads (excerpt):
>>
>> unary-expression:
>> postfix-expression
>> unary-operator unary-expression
>>
>>   . The following question surely serves no practical demand,
>>   but just for the sake of correctly interpreting EBNF:
>>
>>   The above surely allows a unary expression to be preceded
>>   by a finite number of minus signs (unary operators).
>>
>>   When there is an infinite number (say Aleph_0) of minus signs
>>   and then a unary-expression, is this also a unary expression?
> 
> I'll let you know as soon as I finish parsing this infinite input.
> 

What we need here is lazy evaluation.  I have the answer ready
theoretically, as long as you only ask for a small bit of it at a time.

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