Re: LALR parser question

["Yannick Duchêne (Hibou57)" <yannick_duchene@yahoo.fr>]

Le Tue, 30 Apr 2013 19:51:13 +0200, Shark8 <onewingedshark@gmail.com> a  
écrit:
>> I think the parser should read
>> as the humans read, and humans, the most of the time, start looking at  
>> the
>> tiny parts (the bottom) and goes bottom-up, and just occasionally go
>> top-down, and so just when there is a clear marker for this, like a
>> heading title in a text as an example and any other marker which only
>> appears at the top of a construct.
>
> Really, I thought they read in a more top-down manner, with perhaps  
> things front-loaded [i.e. forward-declared] as in sections and a TOC.

To be more precise I would say the reader go top‑down when he/she know  
what he/she is looking for (top‑down for seeking), and bottom‑up when  
he/she do not see the big lines and try to figure what he/she is reading  
(bottom‑up for figuring); as the latter is the case of each new things,  
which in turn is the case when parsing something, I am favouring bottom‑up.

That's oversimplified, I know, I just tried to tell my average though.

I have another reason for my preference for bottom‑up, which is for better  
error “recovering”. For that matter, I agree with GNAT's authors wording.

-- 
“Syntactic sugar causes cancer of the semi-colons.” [1]
“Structured Programming supports the law of the excluded muddle.” [1]
[1]: Epigrams on Programming — Alan J. — P. Yale University