Re: What to put in the try-block
"Erik Wikstr?m" <Erik-wikstrom@telia.com> wrote in news:332f2de4-acb9-
44d9-85af-41e55b846ad3@c23g2000hsa.googlegroups.com:
I just thought of a question that I have never seen discussed before
(perhaps it is trivial?) and while I think I know the answer I realise
that others might have other oppinions, which is why I ask it here.
How much code should one put in the try-block, i.e. if you have code
such as this:
foo;
bar;
baz;
try {
somecode;
}
catch (exception& e) {
// ...
}
and you have to posibility to also put foo, bar, and baz in the try-
block, should you do so?
I think no, since by limiting the stuff in the try-block I more
clearly indicate what might throw (or which depends on something not
throwing) than I do if I put as much as possible in it. Are there any
other oppinions or motivations?
--
Erik Wikstr?m
There are, of course, several of issues to consider. Since anything
declared in the try block is unavailable in the catch block, you
automatically end up with stuff that is at least declared outside the
try/catch construct. I mean, if nothing else, you often want to log
something in the catch block. However, balancing that is the desire to
keep things that logically belong together in the same scope so that it
is obvious that they belong together. So, I guess the points I have
made so far are that you likely to have things outside the try block
anyway, therefore aesthetics doesn't really play into the picture. On
the other hand, code grouping might.
From a practical point of view, the point of a try catch is a form of
flow of control so that you can automatically skip some code if a
predecessor throws. In that case, you will want the code to be skipped
in your try block. In your example, if bar can throw and baz relies on
the results of bar, then you will definitely want both bar and baz in
the try block. This plays more into my own personal view which is that
try/catch is a flow of control statement (though somewhat of a
syntactical heavyweight) and much like an if stmt, you only put the code
in the try block which is useful to be there. Now, I will also say that
I find the try/catch syntax heavy weight enough that I try to have at
most one in a function. This, for me, addresses the code grouping point
above.
Just my opinion.
joe