On 06 January 2004 03:58, Tim L wrote:
> I'm not sure if this is intended behaviour or not, but I can
> see that is
> might be. Just thought I would bounce this to see what
> people think about
> it:
>
> <?php
> if (false)
> ?> Hello<?php
> else
> echo "Hi";
>
> echo " World\n";
> ?>
>
> This returns a parse error due to the fact there is no
> brackets around the
> first part of the if statement.
Yes, but that's only part of the story. What you seem to be neglecting here
is that the closing ?> tag also implies a semicolon, so the above is
equivalent to:
<?php
if (false) ;
echo "Hello"
else
echo "Hi";
echo " World\n";
?>
and I'm sure you can see why that is both syntactically and semantically
invalid.
It's because of this implied semicolon that any conditional or loop in which
you break out of PHP must be enclosed in braces, or use the colon syntax.
The following are valid ways of doing what you want:
<?php
if (false) {
?> Hello<?php
}
else
echo "Hi";
echo " World\n";
?>
if (false):
?> Hello <?php
else:
?> Hi <?php
endif;
echo " World\n";
?>
> It seems that because the
> next line after
> the if is not php, then it terminates the if at the closing
> of the php tag.
As I'm sure you can see now, this is becaue of the implied semicolon.
Possibly the easiest way to work out what's going on when you break in and
out of PHP is just to remember that any time you have a fragment like:
?> something <?php
This is treated like
; echo "something"
(Notice the semicolon at the beginning, and the lack of one at the end!)
>
> But if you do this:
>
> <?php
> if (false)
> ?> Hello<?php
> ?>
>
> or
>
> <?php
> if (true)
> ?> Hello<?php
> ?>
These are syntactically valid because the closing ?> tags imply the
necessary semicolons, but semantically wrong because the first one
terminates the if statement -- so the Hello will be output unconditionally
(and a following else would be syntactically invalid again!).
Cheers!
Mike
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