Re: Interesting article on ARG work

[Niklas Holsti <niklas.holsti@tidorum.invalid>]

On 18-04-10 22:46 , Dan'l Miller wrote:
> On Tuesday, April 10, 2018 at 2:23:24 PM UTC-5, Niklas Holsti wrote:
>> For a GLR parser,
>>
>> _just_ a GLR parser
>>
>> _just_ GLR parsing.
>>
>> In plain GLR parsing
>>
>> That is true for the "Fork-Merge LR" (FMLR) parsing in the paper
>> you referenced, but that is not GLR.
>>
>> _just_ a GLR
>
> Which flavor of generalized LR are you taking as the sole seminal
> reference to definitively brand the official “just GLR” and “plain
> GLR”?  There are 2 seminal references historically:  Bernard Lang
> (1974) and Tomita Masaru (1985).  Lang's versus Tomita's 2 approaches
> to GLR are substantially different.

I just went by the Wikipedia article that you referenced 
(https://en.wikipedia.org/wiki/GLR_parser), which does not mention 
context dependency, and the statement in the FMLR paper that their 
method is different from GLR.

Perhaps our disagreements are partly due to my strict interpretation of 
"parsing" as separate from "semantic analysis", while some people, and 
perhaps you, grant a "parser" the right to depend on context, such as on 
information collected into a symbol table. The symbol table (and its 
dependence on configuration-variable values) is an essential part of the 
FMLR processor.

Perhaps we can conclude this debate by agreeing that the FMLR method can 
process C source, with macros and #ifdefs, and check that all variants 
are syntactically valid, without separately processing /all/ the source 
with /all/ the combinations of configuration-variable values. It still 
cannot be called a "one pass" process, because it splits into 
(conceptually) parallel processes when needed (and, depending on some 
delicate choices, the number of such processes can be exponential in the 
number of configuration variables).

-- 
Niklas Holsti
Tidorum Ltd
niklas holsti tidorum fi
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