• Dan (19/19) Dec 09 2006 How about modifying D to accept a finally clause for use with function/m...
• Jarrett Billingsley (22/43) Dec 09 2006 You can do this with 'out' i.e.
• Stewart Gordon (8/28) Dec 10 2006 What _would_ statements A be for then? Simply to return something if an...

Dan <ddaglas gmail.com> writes:

How about modifying D to accept a finally clause for use with function/method
return values.  For example:

int foo(int a, double b) {
  try {
    ...
    return num;
    ...
  } catch (Exception exc) {
    ...
  } finally {
    ...{statements A}...
  } finally(int retval) {
    ...{statements B}...
  }
}

statements B will execute when the try block executes "return num;", passing
num into the finally clause as "retval".  Whether statements A also executes
in this case is up for discussion.

--Dan

"Jarrett Billingsley" <kb3ctd2 yahoo.com> writes:

"Dan" <ddaglas gmail.com> wrote in message 
news:elf8vj$rqs$1 digitaldaemon.com...
 How about modifying D to accept a finally clause for use with 
 function/method
 return values.  For example:

 int foo(int a, double b) {
  try {
    ...
    return num;
    ...
  } catch (Exception exc) {
    ...
  } finally {
    ...{statements A}...
  } finally(int retval) {
    ...{statements B}...
  }
 }

 statements B will execute when the try block executes "return num;", 
 passing
 num into the finally clause as "retval".  Whether statements A also 
 executes
 in this case is up for discussion.

You can do this with 'out' i.e.

int foo(int a, double b)
out(result)
{
    ...statements B...
}
body
{
    try
    {
        ...return num;
    }
    finally
    {
        ...statements A...
    }
}

But being a contract, it'll only be compiled in non-release mode.  :|

I supposed one workaround would be to just put the result into a local 
variable before returning it, so you can access it in the finally block. 

Stewart Gordon <smjg_1998 yahoo.com> writes:

Dan wrote:
 How about modifying D to accept a finally clause for use with function/method
 return values.  For example:
 
 int foo(int a, double b) {
   try {
     ...
     return num;
     ...
   } catch (Exception exc) {
     ...
   } finally {
     ...{statements A}...
   } finally(int retval) {
     ...{statements B}...
   }
 }
 
 statements B will execute when the try block executes "return num;", passing
 num into the finally clause as "retval".  Whether statements A also executes
 in this case is up for discussion.

What _would_ statements A be for then?  Simply to return something if an 
exception kicks in before the return statement?

I'm not sure about this.  Moreover, the TryStatement syntax already 
suffers from a version of the dangling else problem.  Supporting 
multiple finally clauses might complicate the matter more (not to 
mention break some existing code).

Stewart.