error recovery

[David Goodenough]

djones at megatest.UUCP (Dave Jones) sez:
> Why? For one thing, error-recovery in a recursive descent parser is even
> trickier than in an LR parser!

The hell it is!!!

I suggest you dig out the source of the PDP 11, V6 UNIX C compiler. Written
in C, without YACC, uses recursive descent, and does error recovery so
gracefully, and correctly, it is a pleasure to use. It requires one longjmp
call to recover, but with the exception of a for loop (which could generate
a spurious error about imbalanced parentheses, due to overloading the ';'
operator) it never made a mistake. Would that pcc, the GreenHills family etc.
could do the same.

I'd suggest that all these guys talk to Leor Zohlman, the writer of
BDS-C. I suspect that he uses RD, whatever the case I rate his error
recovery way above _ANYTHING_ I have come across in UNIX since the V6
days. Are you listening guys????
-- 
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