Why does try/catch require {}

[John Bailo]

how come I can say:
if() statement; else statement;

but I cannot say

try statment; catch() statement;
I always have to use {}

[Marina]

Because it is less often that a try or a catch would have only 1 statement
in it. Typically, it will have many statements in it (especially the Try).
Whereas with 'if' statement, having only one statement you want to execute
is very common.

The actual reason is probably not having to do extra work with building it
in to the compiler. They would have spent extra time on something that
wasn't going to be used often.

Is it really a big deal to put the {} in there?

"John Bailo" <ja*****@texeme.com> wrote in message
news:2M*****************************************@s peakeasy.net...

how come I can say:
if() statement; else statement;

but I cannot say

try statment; catch() statement;
I always have to use {}

[Jon Shemitz]

John Bailo wrote:

how come I can say:

if() statement; else statement;

but I cannot say

try statment; catch() statement;

I always have to use {}

I've wondered about that, too. Seems like a fairly large
inconsistency, and one that grates every time I write a one statement
catch or finally block. Just makes the code take more screen space.

Laziness seems the most likely answer. My best guess is that somehow
it's significantly easier to create the try table (in the metadata)
and to emit the special leave instructions when you have the { and }
tokens as a trigger than if you have to do this for a simple
statement.

But I suppose it's also possible that 'try statement catch
exception-block' creates some parser ambiguities that 'try
compound-statement catch exception-block' does not. I haven't actually
looked at a formal grammar for C# ....

--

www.midnightbeach.com

[gmiley]

I believe that it is best-practice to use {} for any code block
regardless of its length.

We have made that part of our coding standards here.

If you are just coding for yourself, that is a different situation, do
it however you like, but when several people are working in the same
code then requiring each if(), for(), while(), foreach(), et al use the
formatting of:

if (expression)
{
// do this
}

.... ends up making it easier for everyone involved.

As for the technical side of why they require {} for try/catch, well -
not a clue here.

I just know that I would hate to see:

try System.Data.DataRow = dataTable.Rows[0];
catch(System.Data.DataException ex) HandleError(ex); finally
dataTable.Dispose();

[Jon Shemitz]

gmiley wrote:

I believe that it is best-practice to use {} for any code block
regardless of its length.
I know that a lot of people agree with you.

Obviously, I don't. I think that turning one line into three just adds
bulk and cuts clarity. I don't buy the "argument from maintainability"
- it's not at all hard to add the {} as needed and, in the VS
environment (ie, with a nice auto-formatter) it's all but impossible
to misread

if (tst)
statement1;
statement2;
We have made that part of our coding standards here.

How ... special. Does that have anything to do with try/catch syntax?

--

www.midnightbeach.com

[Bruno Jouhier]

because the Java try/catch requires braces and C# copied it.
This does not explain why the Java try/catch requires braces, though.

Bruno

[Helge Jensen]

/me bears wood to the stake and looks for matches ;)

--
Helge Jensen
mailto:he**********@slog.dk
sip:he**********@slog.dk
-=> Sebastian cover-music: http://ungdomshus.nu <=-

[gmiley]

> We have made that part of our coding standards here.

How ... special. Does that have anything to do with try/catch syntax?

---

Not directly - no, except that in our case where it's required to use
{} for all code blocks, questions such as the original "Why does
try/catch require {}" do not exist.

---

I don't buy the "argument from maintainability"
- it's not at all hard to add the {} as needed and, in the VS
environment (ie, with a nice auto-formatter) it's all but impossible
to misread

if (tst)
statement1;
statement2;

---

Buy the argument or not, but when you have to go through 10,000 lines
of code littered with evaluation/flow-control statements that do not
use {} and find that you need to add more instructions to those blocks,
you will be pounding your head wishing it had been done in the first
place.

I agree, VS does a nice job at formatting, but as general practice
(language/environment/etc non-specific) you cannot write code, as a
team-member, that relies on the IDE you prefer to use.

It's not just a matter of readability, or maintainability - it's a
matter of propper programming practices in a multi-author environment.

I'm not telling anyone they HAVE to do it a certain way - I was simply
stating my opinion on how to make the argument moot. Create standards
to be adhered to, one of which was the requirement of {} for all
code-blocks regardless of how many lines it might be at the time.