Re: LR(1) Parsing : Error Handling & Recovery

Hello,


On 7/16/14, 11:39 PM, Ivan Godard wrote:
> FWIW, I recall hearing that GCC switched from LR1 (LALR?) to
> recursive-descent a few years back.


Yes, gcc switched to a hand-coded parser; the gcc team claimed that one
of the benefits was diagnostic location improvements (and potentially
other diagnostic improvements);see https://gcc.gnu.org/wiki/New_C_Parser


But, I guess they could say the same thing if they replaced the hand
coded Fortran parser with a LALR parser. Ibve compared recently an
enhanced LALRb parser with gfortran; the former has better error
recovery and in many cases more accurate error messages whereas the
latter sometimes just prints the clichC) bUnclassifiable Statementb.


Anyway, other implementers (e.g. clang team) also confirm that C++ is
best parsed by a recursive descent parser; Ibve not created a C++ parser
and cannot comment on it.


Regards,
Ev. Drikos

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