Re: pgindent vs try/catch - Mailing list pgsql-hackers

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Bruce Momjian wrote:

| Gaetano Mendola wrote:
|
|>>I had that argument a while ago with Bruce and lost :-) . It does horrible
|>>things to if/else constructs too. The workaround is to put a comment in the
|>>block. On the whole I agree with you, though. If I put braces in my program
|>>it's for a reason, and the indenter shouldn't think it knows better than me.
|>
|>Well I'm not exactly a C coder, I'm a C++ one and it's quite common use the
|>extra scope in order to reduce the automatic variable life, I don't know how
|>much the extra scope are used in the C world, however remove an "extra scope"
|>like that is not only "horrible", is *wrong* and can be cause of future pain:
|>
|>
|>foo (  int a )
|>{
|>   ...
|>   {
|>       int a;    
|>   }
|>   // use the formal parameter
|>}
|>
|>if the extra scope is removed the local variable "shadow" the formal
|>parameter. Some compilers do not warning you, IIRC the Digital had this funny omission,
|>( however you can miss the warning ) and hours of debugging are behind the corner.
|>I hope that Bruce change his mind...
|
|
| I am a little confused by the above.  It only removes braces that have
| one command in them.

This was not clear to me.


| What does "use the formal parameter" mean?

Emm, the variable argument I mean, is not "formal parameter" the right name ?


| FYI, C doesn't allow variables to be declared in for() like that, but I am
| still curious how C++ handles such cases.

the { ... } in c++ represent an extra scope this means that at the end of the
scope all variable declared inside are destroyed. A common way to use it is to
surround critical sections:

void foo( int a )
{
~  Mutex m;
~  ...
~  {
~     Lock myLock(m);   // The lock is acquired inside the constructor
~     int a = 5;
~     //critical section code follow
~     ...
~  }         // The unlock is performed in the destructor
};

at the end of the scope the destructor for the variable myLock is called.
In this way the lock is released ( with the appropriate code in the destructor)
without remember to unlock it and most important the lock is released also if
an exception is thrown; inside that extra scope the variable
"a" hide the function parameter, this code is perfectly legal in C++.

In the case of the for if you declare for ( A a = ... ) {    } the lifespan
for the object a is the "for" body, and ansi C++ allow the reuse so you can have:

for ( A a = ... ) {    }
for ( A a = ... ) {    }


| I have no problem in removing this pgindent behavior.

I don't know all the implication in removing it or leave it, however I agree to
leave the extra scope in place.







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