Re: recovery from syntax errors, was "ignorant newbie" question

Dennis Yelle <dennis@netcom.com> wrote:
> >It seems obvious that you cannot produce a compiler that will always
> >give a correct second error message, because the compiler cannot know
> >what I actually intended in place of the first error.


Norman Ramsey wrote:
> Um, it may seem obvious, but it's not. The algorithm I described
> ``taints'' everything that could possibly depend on the first
> erroneous construct, and it refuses to issue error messages about
> tainted things. That way it can produce reliable error messages about
> other parts of your program, which don't depend on the first error.


It occurs to me that the second and subsequent errors returned from
your system as described, may result from code that was *supposed* to
depend on the code containing the first error, but which, due to the
first error did not.


Everything in the program, either does or does not depend on the part
of the program in which the error was found; but the simple fact of
the error can easily screw up your ability to determine which category
a piece of code falls into.


Bear
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