<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
</head>
<body>
<p><br>
</p>
<div class="moz-cite-prefix">On 1/24/25 8:12 AM, Hairy Pixels via
fpc-pascal wrote:<br>
</div>
<blockquote type="cite"
cite="mid:CAGsUGtnPbF6TrHdNM7ckBQWP63EYej8aFzarh=V1VgiOQ0yhdQ@mail.gmail.com">
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<div class="gmail_quote">
<div dir="ltr" class="gmail_attr">On Jan 24, 2025 at
12:43:51 PM, Nikolay Nikolov via fpc-pascal <<a
href="mailto:fpc-pascal@lists.freepascal.org"
moz-do-not-send="true" class="moz-txt-link-freetext">fpc-pascal@lists.freepascal.org</a>>
wrote:<br>
</div>
<blockquote class="gmail_quote"
style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"
type="cite"> That's not what exceptions are meant to be used
for, though. What you describe is called a program "defect".
When you encounter a "defect" in your program, you terminate
the program. The proper handling of a defect is to fix
(modify) the program, so it doesn't happen again. In the case
of a "defect", there's no much point in freeing the memory,
because all of the program's memory is freed anyway, when the
process terminates. An exception is used for reporting an
unanticipated condition, encountered at runtime. A program can
be correct (bug free) and still encounter exceptions. For
example, a web browser might encounter a network error, during
the loading of a web page, in which case, it should report the
error to the user in its GUI, and it should continue operating
normally, instead of crashing, so the user can continue
browsing, by e.g. trying again, or typing in a different URL,
or switching to a different tab, etc.<br>
</blockquote>
<div class="gmail_quote"><br>
</div>
<div class="gmail_quote" dir="ltr">Yes I know I’m just saying
that’s the most I’ve done with them in Pascal. I do use them
to escape deep recursion too and then they’re very helpful but
I would have random allocations in a recursive that could fail
randomly at any point.</div>
<br>
<blockquote class="gmail_quote"
style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"
type="cite">Feels to me like manual memory management and
exceptions don’t mix well.<br>
I fail to understand how you came to this conclusion, since I
just showed how the same code would look without exceptions,
and it's way worse.<br>
<br>
</blockquote>
<div class="gmail_quote"><br>
</div>
<div dir="ltr">That example was the best scenario for exceptions
where they’re handled in the same scope they occur and they
don’t bubble up through the call stack.</div>
</div>
</blockquote>
Doesn't matter whether they're handled in the same scope or not.
It's the same code. Usually they're not handled in the same scope,
but in a very distant place. That's usually when exceptions are
convenient.<br>
<blockquote type="cite"
cite="mid:CAGsUGtnPbF6TrHdNM7ckBQWP63EYej8aFzarh=V1VgiOQ0yhdQ@mail.gmail.com">
<div class="gmail_quote">
<div dir="ltr"> Once you let them bubble up you need to wrap all
call sites with try..finally right?</div>
</div>
</blockquote>
<p>Wrong. Only sites that allocate memory, that needs to be freed,
before leaving the scope need a try..finally. You don't need to
wrap every call. That's nonsense. The pattern is:</p>
<p>var</p>
<p> {... initialize local vars you're going to allocate in this
function with nil}<br>
</p>
<p>begin</p>
<p> try</p>
<p> {lots of code, allocations, calls, etc}</p>
<p> finally</p>
<p> {cleanup code}</p>
<p> {free stuff that isn't nil}<br>
</p>
<p> end;<br>
</p>
<p>end;</p>
<p><br>
</p>
<p>Nikolay<br>
</p>
</body>
</html>