Re: stopping a loop iteration without exiting it

[Matt Borchers <mattborchers@gmail.com>]

I would like to also put my voice in for a 'next [when condition]' statement.  It is also my opinion that in some cases it is more readable.  I would avoid 'continue' only because it is a C term.  The use of 'goto' in a loop to act like a next by jumping to the END of the loop seems more like a hack and I agree with the sentiment that it adds more confusion for the reader.

Regarding performing a sequence of statements conditionally after a loop comes up quite a bit in my experience.  In our proprietary language we have a loop...then...end loop construct.  The 'then' block executes when the loop terminates normally (not terminated by an 'exit').  This can be useful when you want to do some action following the loop only when the loop runs 'cleanly' and it avoids having to create a Boolean flag variable to set in the loop with the addition of an 'if' statement and then have to test the flag following the loop with another 'if' block.

A similar situation occurs frequently with exceptions.  I would like to see a 'finally' block added after the 'when' conditions that runs after any handler is run.

begin
...
exception
  when EX1 => ...
  when EX2 => ...
  when others => ...
finally
...
end;

This would allow programmers to handle common cleanup operations that would otherwise have to be duplicated in every exception case.  This is mostly useful if the code was going to re-raise the exception or return control to the caller in the exception handler.  Control would be returned to the caller after the 'finally' block if it exists otherwise the program flow behaves as it does now.

These three examples, 'next', loop...'then'...end, 'finally', all allow the programmer to produce constructs without having to introduce extraneous variables, blocks, or sub-routines to track state which, in my opinion, can often make the code more difficult to read.