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<TITLE>5.12 Wholistic Debugging</TITLE>
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<P><FONT SIZE="5">5.12 Wholistic Debugging</FONT><BR>
<P>Surprising though it may be, FunnelWeb has a role
to play in the <STRONG>debugging</STRONG> of programs. My
experience in programming has led me to the concept of
<STRONG>wholistic debugging</STRONG>. When many programmers
detect a bug, their first reaction seems to be to jump into
the debugger where they often spend many
hours stepping through endless stretches of code and
generally wasting a lot of time.
<P>In contrast, my first reaction when I detect a bug is
to realize that <STRONG>the code must not be in good enough
shape if such a bug can arise!</STRONG> The presence of the bug is
taken as symptomatic of the lack of general health of the
code. If that bug occurred, why not another? In response to
this realization, my reaction is not to enter the debugger,
but rather to return to the original code and tend it like a
garden, adding more comments,
reworking the weaker parts, adding assertions, and looking
for faults. In many cases, the search for faults does not
even centre on the specific bug that arose, but does tend to
focus on the area of code where the bug is likely to be.
<P>The result is often that the original bug is located
more quickly than it would have been had the debugger been
involved. But even if it isn't, there are other benefits. A
programmer who enters the debugger may stay there for hours
and still not find the bug. The result is frustration and no
positive gain at all. In contrast, by tending to the code,
the programmer is making forward progress at all times (the
code is constantly improving) even if the bug is not
immediately found. At the end of ten hours, the programmer
can at least feel that the code is "ten hours
better", whereas the debugger freak will likely feel
defeated. All this makes code tending better psychologically
as well as a more efficient approach to debugging.
<P>I call this technique wholistic debugging, for it is
like the difference between conventional and wholistic
medicine. Go to a conventional
doctor with a headache and he might send off for head
X-rays, perform allergy tests and perform many other
debugging activities. Go to a wholistic doctor with the same
problem and he might look to see if you are fit, assess your
mental health, and ask you if your marriage is working. Both
approaches are appropriate at different times, but I believe
that, on balance, in programming the wholistic approach is
not used enough.
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