Here's another ponder from the random files of Russ:



consider this code:

ReadInput();
while(!InputIsValid())
{
    PrintError();
    ReadInput();
};



This is fairly common code in a lot of my programs.  Ofc, instead of ReadInput(), I find that I have a line or three of code.  It would be advantageous to be able to avoid the duplication of the ReadInput() call.  Sometimes I do this by turning it into a false infinite loop:


while(1)
{
    ReadInput();
    if(InputIsValid())
      break;
    else
       PrintError();
};


But that's hard to read.  It would be nice to be able to add a block of loop-only code.  I don't have a good syntax, here's just a ponder:

do
{
    ReadInput();
} while(!InputIsValid())
loop
{
    PrintError();
};

Thoughts?


--
The Villagers are Online! villagersonline.com

.[ (the fox.(quick,brown)) jumped.over(the dog.lazy) ]
.[ (a version.of(English).(precise.more)) is(possible) ]
?[ you want.to(help(develop(it))) ]

"Russ Lewis" <spamhole-2001-07-16@deming-os.org> wrote in message news:3BF92FF6.523E98C3@deming-os.org...

> ReadInput();
> while(!InputIsValid())
> {
>     PrintError();
>     ReadInput();
> };
>
> This is fairly common code in a lot of my programs.  Ofc, instead of ReadInput(), I find that I have a line or three of code.  It would be advantageous to be able to avoid the duplication of the ReadInput()

What about this:

    while(ReadInput(), !InputIsValid())
        PrintError();

Right, that's possible.  But, IMHO, that's even less readable than the infinite-loop thing.  Besides, I'm using ReadInput() for example clarity...in reality it's usually something far more complex, probably multiple lines.



>     while(ReadInput(), !InputIsValid())
>         PrintError();

--
The Villagers are Online! villagersonline.com

.[ (the fox.(quick,brown)) jumped.over(the dog.lazy) ]
.[ (a version.of(English).(precise.more)) is(possible) ]
?[ you want.to(help(develop(it))) ]

How about this syntax:

do
{
  ReadInput();
} if (!InputIsValid())
{
  PrintError();
}

or maybe this:

while (
    {
        ReadInput();
        ....
    },
    !InputIsValid()
    )
{
  PrintError();
}

or even this:

while
{
    ReadInput();
    ....
}
( !InputIsValid() )
{
  PrintError();
}

Wierd.  Would be a nice handy control structure though.

Sean

"Russ Lewis" <spamhole-2001-07-16@deming-os.org> wrote in message news:3BF92FF6.523E98C3@deming-os.org...
> Here's another ponder from the random files of Russ:
>
>
>
> consider this code:
>
> ReadInput();
> while(!InputIsValid())
> {
>     PrintError();
>     ReadInput();
> };
>
>
>
> This is fairly common code in a lot of my programs.  Ofc, instead of ReadInput(), I find that I have a line or three of code.  It would be advantageous to be able to avoid the duplication of the ReadInput() call.  Sometimes I do this by turning it into a false infinite loop:
>
>
> while(1)
> {
>     ReadInput();
>     if(InputIsValid())
>       break;
>     else
>        PrintError();
> };
>
>
> But that's hard to read.  It would be nice to be able to add a block of loop-only code.  I don't have a good syntax, here's just a ponder:
>
> do
> {
>     ReadInput();
> } while(!InputIsValid())
> loop
> {
>     PrintError();
> };
>
> Thoughts?
>
>
> --
> The Villagers are Online! villagersonline.com
>
> .[ (the fox.(quick,brown)) jumped.over(the dog.lazy) ]
> .[ (a version.of(English).(precise.more)) is(possible) ]
> ?[ you want.to(help(develop(it))) ]
>
>